The Surveillance of Communicable Diseases
- DOI:
- 10.1093/med/9780199596614.003.0002
2.1 Introduction [link]
Layout of Chapter [link]
2.2 Disease Classification and Recording: General Considerations [link]
2.3 Early Surveillance Systems: Local Bills of Mortality [link]
2.4 National Surveillance: The United States [link]
2.5 International Health Cooperation: Before the League of Nations [link]
2.6 Wireless Technologies: The League of Nations Health Organisation (1923–46) [link]
2.7 Wireless to Internet: The World Health Organization (1946–) [link]
2.8 Evolving Surveillance Practices [link]
2.9 Conclusion [link]
Appendix 2.1: Communicable Disease Categories [link]
If we are to control the spread of a communicable disease, knowledge by surveillance of the existence – where, when and how much – of a disease is a necessary prerequisite (Figure 2.1). Although the idea of using morbidity and mortality data as a basis for public action to inhibit the spread of infection can be traced back to medieval times (Chapter 1), the modern concept of ‘disease surveillance’ as a scientific basis for such action rests with the establishment of the US Communicable Disease Center in 1946. Beginning with the national malaria control programme, the mandate of the Center was to initiate the investigation of health events through the systematic collection and analysis of morbidity and mortality data. In 1955, the term ‘disease surveillance’ was applied to these activities by Alexander D. Langmuir, chief epidemiologist (Figure 2.2), who defined disease surveillance activities as:
the continued watchfulness over the distribution and trends of incidence through the systematic collection, consolidation and evaluation of morbidity and mortality reports and other relevant data. Intrinsic in the concept is the regular dissemination of the basic data and interpretations to all who have contributed and to all others who need to know
Source: (Lower) Fee, et al. (2008, Image 1, p. 630), reproduced courtesy of the World Health Organization.
Source: CDC (Public Health Image Library ID #8148).
At the global level, Langmuir (1976) observes that the term ‘surveillance’ was given expanded meaning in the course of the World Health Organization’s Malaria Eradication Programme (Section 5.4) and was extended to embrace active measures of control such as the administration of chemotherapy and the use of insecticides. In the Smallpox Eradication Programme (Section 5.2), the term became synonymous with containment, including the delivery of vaccines. Subsequently, the US Centers for Disease Control and Prevention (CDC), successor to the Communicable Disease Center, has defined disease surveillance as the:
Ongoing systematic collection, analysis and interpretation of health data in the process of describing and monitoring a health event. This information is used for planning, implementing, and evaluating public health interventions and programs
An understanding of the purposes and methods of data compilation under the aegis of disease surveillance is a necessary prerequisite to effect analysis of the resulting data. Disease surveillance systems vary in method, orientation and scope depending upon the nature of the health event being observed, and they thus vary in their simplicity, acceptability, sensitivity, representativity and timeliness (Centers for Disease Control, 1988).
Layout of Chapter
In this chapter, we focus upon the role of surveillance in informing control strategies for communicable diseases. We begin in Section 2.2 by examining how morbidity and mortality are recorded and classified to form the basis of surveillance systems. In Sections 2.3–2.8, we examine the business of gathering surveillance data over time and space, beginning with the earliest systematic data recording, the bills of mortality for London and other cities in Europe and North America (Section 2.3). Geographically, the bills are local-scale. In Section 2.4, we move up the geographical scale to national surveillance systems, as well as forward in time, and study the evolution of surveillance systems in the United States from colonial days to the present. Sections 2.5–2.7 shift up the geographical scale yet again to the world regional and global levels by examining international disease surveillance articulated through such historical bodies as the Office International d’Hygiène Publique and the League of Nations Health Organisation and, today, through the World Health Organization. Over time, collection strategies have evolved in response to changing technologies, from pen and paper, through the electric telegraph, paper tape and punch cards, to the worldwide reach and instantaneity of the Internet. The Internet-age has spawned a number of ‘informal’ real-time disease surveillance mechanisms, while enhancing the opportunities for multiple-source disease tracking tools. At the same time, the global range of diseases and the global population have mushroomed, so that the blanket surveillance of former times is now evolving into sampling procedures by time, disease and geographical location. These developments form the basis of the chapter’s final substantive section, Section 2.8.
2.2 Disease Classification and Recording: General Considerations
Disease Classifications
Early attempts to devise a systematic classification of diseases include the works Nosologia Methodica by François Bossier de Lacroix (1706–77) in 1763, Genera Morborum by Linnaeus (1708–78) in 1759, and Synopsis Nosologiae Methodicae by William Cullen (1710–90) in 1785. Major advances in disease classification, however, awaited the mid-nineteenth century and the First International Statistical Congress, held in Brussels in 1853 – the first in a series of nine meetings with the underpinning aim of achieving uniformity in national statistics. The Congress requested that both William Farr of London and Marc d’Espine of Geneva should prepare uniform classifications of causes of death that were internationally applicable. A compromise list of 138 rubrics was agreed at the next Congress in 1855. Much revised at subsequent meetings, the Farr–d’Espine list formed a basis for the present International Classification of Diseases (ICD) which began formally in Chicago in 1893 with the adoption by the International Statistical Institute of Bertillon’s International List of Causes of Death. In 1898, the American Public Health Association recommended the adoption of the Bertillon classification by the civil registrars of Canada, Mexico and the United States, adding that the classification should be revised every 10 years. The first revision of the Bertillon classification appeared in 1903 (Figure 2.3). Since that time, the classification now known as the ICD has gone through a total of 10 revisions and runs to several weighty volumes (World Health Organization, 2011a).
The ICD is the international standard diagnostic classification for all general epidemiological and many health management purposes. It is used to classify diseases and other health problems recorded on health and vital records including death certificates and hospital records. The idea of such a classification is to ensure comparability of data recording over space and time, thus facilitating the storage and retrieval of diagnostic information for clinical and epidemiological purposes. These records also provide the basis for the compilation of national mortality and morbidity statistics by country-level surveillance organisations. The latest (tenth) classification (ICD-10) came into use in WHO Member States from 1994; see www.who.int/classifications/icd/en for a history.
Figure 2.4A shows the time series of the number of infectious diseases appearing in the ICD since its inception. The diseases included are those in the so-called A and B lists. The number of diseases listed remained at around 100 for the first 65 years of ICD’s existence. In the ninth and tenth revisions, however, the number rose sharply from around 350 (ICD-9) to over 1,000 (ICD-10). Figure 2.4B gives, on the same decennial basis, the dates of discovery of the main disease agents which have shaped this curve. The switch from bacterial to viral agents identified over the course of the twentieth century is evident.
Source: redrawn from Cliff, Smallman-Raynor, Haggett, et al. (2009, Figure 1.8, [link]).
Disease Collecting Systems
Primary Surveillance Networks
The various routes by which a case of a particular disease may enter the statistical record at the primary (local) level are shown schematically in Figure 2.5. The left-hand path describes a reactive process in which an individual may experience symptoms of a disease but may or may not be able (or inclined) to visit a medical practitioner. Such a consultation may or may not result in a correct diagnosis and the physician may or may not have to pass the record up the reporting chain. Primary data collection by general practitioners, consultants, hospital clinics and others may or may not become part of a country’s official disease records. Only diseases of major public health importance are subject to statutory notification (that is, notifiable by law) and the quality of the data record will depend on many factors: the complexity of the disease and associated complications; the diagnostic skill of the physician; the case load of other clinical work, and so on. The routine reporting of some diseases is supplemented by the right-hand path in Figure 2.5. This path describes a proactive process in which screening or surveys of ‘healthy’ or ‘at risk’ populations may reveal evidence of infection or disease (for example, HIV/AIDS or tuberculosis) either unrecognised by the individual or for which medical advice had not been sought in the first instance.
Secondary Surveillance Networks
Figure 2.6 shows the reporting routes whereby disease-related information finds its way from the primary level, via secondary reporting routes of varying complexity, to national (e.g. the Health Protection Agency in the United Kingdom and the Centers for Disease Control and Prevention in the USA) and to international recording agencies like the World Health Organization.
Time Span of Disease Records
The availability of disease data varies greatly over time. As we shall see in Section 2.3, a written record of the incidence of some diseases goes back to the sixteenth century for a few great cities. Before this, historical and even prehistoric archaeological records can cast a dim and fitful light on the presence or absence of a few specific diseases. With improvements in DNA testing on palaeo-pathological specimens, there is hope for some extension. But, as Figure 2.7 shows, there is little consistent archival material until the second half of the nineteenth century. At this time, legislation was passed in the United States, Scandinavia and Great Britain which ensured disease records were kept for afflictions considered to be of public health importance to national populations. As described earlier, internationally-endorsed classifications of causes of death (and, later, causes of morbidity) which could be used by international agencies for the compilation of disease statistics became available in the early twentieth century. From that time, international agencies such as the Pan American Sanitary Bureau, the League of Nations Health Organisation and the World Health Organization have served as sources of international data on health and disease.
In interpreting Figure 2.7 it is important not to assume that disease recording over time has become ever more accurate. In recent decades, the recording of some common diseases has been downgraded as their incidence and perceived threat have fallen. In some countries, disease recording has moved from statutory reporting of all recognised cases to one of sampling and surveillance using devices such as ‘sentinel’ medical practices.
Sources of Disease Data
Over the centuries, many sources of disease-related data have developed. These include: mortality registration; morbidity case reporting; epidemic reporting; laboratory reporting; individual case reports; epidemic field investigations; surveys; animal reservoir and vector distribution studies; and demographic and environmental data (Declich and Carter, 1994). To these can be added: hospital and medical care statistics; general practitioner records; public health laboratory reports; disease registries; drug and biologics utilisation and sales data; absenteeism data; health and general population surveys; and media reports. Different data sources present their own advantages and disadvantages. Their availability varies from country to country and they differ in their level of sophistication, quality, utility and extent.
2.3 Early Surveillance Systems: Local Bills of Mortality
The early history of bills of mortality, which were printed or written abstracts from parish registers of the number of people who had died in a given place and time (Figure 2.8), is reviewed by Walford (1878). Ancient Rome had bills in the form of Rationes Libitinæ, maintained in the Temple of Libitina, the Goddess of Funerals. The Temple of Libitina, in which the last rites were transacted, served as a registration office, and an account (ratio ephemeris) was kept of those who died (Walford, 1878). In modern form, bills of mortality date to the sixteenth and seventeenth centuries. The London Bills of Mortality (Figure 2.8A) represent one of the earliest examples of a disease surveillance system in that they involved data collection and analysis, interpretation and dissemination of information for action in the context of the repeated plague epidemics in the late sixteenth and seventeenth centuries (Declich and Carter, 1994), and the London Bills form our point of departure in this section.
Source: (A) Wellcome Library, London.
The London Bills of Mortality
The history of the London Bills of Mortality is reviewed by Marshall (1832) and Walford (1878) and we draw on their accounts here. The Bills originated in the sixteenth century as a device for providing the Royal Court with warning when plague was abroad in the city. Responsibility for the preparation of the Bills rested with the Parish Clerks of London, with the first known Bills issued in the plague year of 1532 and then irregularly throughout the remainder of the sixteenth century as and when plague appeared in the city. Regularity was established early in the seventeenth century, with the first of the uninterrupted series of weekly Bills appearing in December 1603 and the first of the annual Bills from 1606. In 1625, the Worshipful Company of Parish Clerks obtained a decree under the seal of the High Commission Court (Star Chamber) to establish a printing press in their hall and, for this purpose, a printer was assigned by the Archbishop of Canterbury. The quantity of information included in the Bills expanded from thereon, with the number of burials in each parish included from 1625, specific causes of death (other than plague) from 1629 and, somewhat later, age at death from 1728. Publication of the Bills continued until the mid-1830s, when they were superseded by the Returns of the Registrar General.
Surveillance Operations, Geographical Reach and Data Quality
For the purpose of data collection, the Parish Clerks appointed two female ‘searchers’ in each parish. A contemporary account of the duties of the searchers is provided by John Graunt:
When any one dies…The Searchers hereupon (who are ancient Matrons, sworn to their office) repair to the place, where the dead Corps lies, and by view of the same, and by other inquiries, they examine by what Disease or Casuality the Corps died. Hereupon they make their Report to the Parish-Clerk, and he, every Tuesday night, carries in an Accompt of the Burials, and christenings, happening that Week, to the Clerk of the Hall. On Wednesday the general Accompt is made up, and Printed, and on Thursdays published, and dispersed to the several Families, who will pay four shillings per Annum for them
The progressive expansion of the area encompassed by these surveillance operations is mapped to the mid-eighteenth century in Figure 2.9. When regular reporting began in 1603, the activities of the searchers were limited to an area of approximately 1,853 acres, encompassing 96 parishes within the walls of the city and several out-parishes. The inclusion of the City of Westminster and several out-parishes in Middlesex and Surrey contributed to a threefold increase in the area under surveillance by the late 1620s, while the incorporation of the parishes of Hackney, Islington, Lambeth, Newington, Rotherhithe, Stepney, Poplar and Bethnal Green brought the total area covered by the Bills to over 22,500 acres by the mid-1600s. The geographical reach of the Bills was further extended as the city grew over the following century (Walford, 1878) (Figure 2.9).
Source: drawn from information in Marshall (1832).
Contemporary views on the quality of the information included in the London Bills are provided by Graunt (1662) and, towards the end of their compilation, Marshall (1832); Landers (1993, [link]–[link], 193–4) and Boulton and Schwarz (2010) provide more recent perspectives. Suffice it to note here that, officially, the Bills only include information relating to burials within Anglican grounds. Even then, it seems doubtful that the records are entirely accurate and both systematic and random elements impinge on the confidence that can be placed in the available data; see Cliff, Smallman-Raynor, Haggett, et al. (2009, [link]).
The Investigations of John Graunt
Although many contemporary physicians held the Bills in contempt, not least because “they were based on the diagnoses of ignorant women” (Gale, 1959, [link]), a mid-seventeenth-century analysis of their content by John Graunt (1620–74), a haberdasher by trade, allowed him to establish some of the fundamental principles of public health surveillance. Graunt’s observations were published in Natural and Political Observations Made upon the Bills of Mortality in 1662 (Figure 2.10), where the motivation for his investigations was laid out:
Having been born, and bred in the City of London, and having always observed, that most of them who constantly took in the weekly Bills of Mortality, made little…use of them…I casting mine Eye upon so many of the General Bills, as next came to hand, I found encouragement from them, to look out all the Bills I could…which, when I had reduced into Tables…I did then begin, not onely to examine the Conceits, Opinions, and Conjectures, which upon view of a few scattered Bills I had taken up; but did also admit new ones, as I found reason, and occasion from my Tables
Through his tables, Graunt developed the fundamental principles of disease-specific death counts and death rates; he attempted to define the basic laws of natality and mortality; and he is generally credited as the first to estimate the population of the City of London (Declich and Carter, 1994; Thacker, 2010).
Historical Mortality Patterns
The Bills of Mortality have informed a substantial literature on the historical demography and mortality of London since Graunt’s time, including the major studies and overviews of Creighton (1891–94), Finlay (1981), Matossian (1985) and Landers (1993). Because the data in the Bills are temporally and spatially coded, both longitudinal and spatial analyses are possible as the following examples show.
Temporal series
The graphs in Figure 2.11 plot the estimated annual burial rate per 1,000 population in London for all causes (graph A) and seven sample communicable diseases (graphs B–H), 1603–1829. Consistent with the early stages of Omran’s epidemiological transition model (Omran, 1971), graph A shows a high background level of burials (30–50 burials per 1,000), punctuated by a series of plague-related ‘mortality crises’ in 1603, 1625, 1636 and 1665. From the mid-eighteenth century, overall burial rates began a secular decline that continued until the end of the series.
In addition to the sample communicable diseases shown in Figures 2.11B–H, many others were long-present in London but were not formally recorded in the Bills as separate disease categories until relatively recent times – an indicator of growing medical awareness of the conditions. Influenza, for example, emerged from the ‘epidemic agues’ as a distinct clinical entity in the Bills at the end of the eighteenth century, while scarlet fever was formally differentiated from fevers, measles and other causes of death in the 1830s, “long after it had become an important factor in…mortality” (Creighton, 1891–94, Vol. II, p. 719).
Spatial cross-sections: plague
As we have noted, the original purpose of the Bills was to provide warning when plague was abroad in London so that its great citizens could retire to the relative epidemiological security of the countryside. Up to 1665, the city was subjected to repeated plague epidemics (Figure 2.11D). Some impression of the spatial manifestation of a sample of these events (1593, 1625, 1636 and 1665) can be gained from Figure 2.12. Here, circles plot the total number of burials from all causes in aggregations of parishes; shaded segments indicate the proportion of burials that were plague-related. The Great Plague of London in the year 1665 stands out as a particularly dramatic event (Figures 2.8A, 2.11D and 2.12D). This epidemic is reputed to have begun in the slums of St Giles, in the Fields (then a London out-parish) to the west of the city, spreading thereafter to the east and south and resulting in 68,596 recorded deaths by the end of the year (Creighton, 1891–94, Vol. I, pp. 646–92).
Source: drawn from data in Marshall (1832, [link]).
Bills for Other Cities: Continental Europe and North America
Continental Europe
Early Italian ‘bills’: Books of the Deceased
Cipolla (1978) reports that ‘bills of mortality’ for some cities of northern Italy become available from the late fourteenth century: Florence (1385), Milan (1452), Bologna (1456), Mantua (1496) and Venice (1504). The bills for these cities were not published at the time but were compiled in unpublished Books of the Deceased and held in city archives. With the exception of Bologna, the registration of deaths on which the bills were based were independent of vital registration at the parish level, and the motivation for their collation ranged from demographic accounting to epidemic intelligence. In Florence, for example, two series of Books of the Deceased were compiled: (1) a 20-volume series, 1385–1778, compiled by the Board of the Grascia and concerned with provisioning for the city; and (2) a 23-volume series, 1450–1808, compiled by the Guild of Physicians and Apothecaries. Both series were compiled from information supplied by the town’s gravediggers, although the material contained in the two series does not always agree. More generally, deaths in hospitals were omitted from the records of both series, while deaths of children were only erratically and incompletely recorded – the latter, probably, because these were viewed as a normal fact of life (Cipolla, 1978).
Other European countries
Bills of mortality had come into general usage in many parts of Europe by the second quarter of the eighteenth century, as revealed by Sir Conrad Sprengell’s extracts of bills for ‘considerable towns’ in Austria (Lobau, Vienna), Denmark (Copenhagen), Germany (Berlin, Dresden, Erfurt, Freiberg, Leipzig, Nurenberg, Weimar), Netherlands (Amsterdam) and Poland (Breslau, Danzig) (Sprengell, 1727). Of these, the bills for Breslau are of particular historical significance as they formed the basis for the first modern life table, constructed by Edmund Halley and published in the Philosophical Transactions of the Royal Society in 1693 (Halley, 1693; Bellhouse, 2011) (Figure 2.13).
Sources: (A) Wellcome Library, London.
North America
Books of births, marriages and deaths for the city of Boston, Massachusetts, can be traced back to the 1630s. Between 1701 and 1774, the keepers of burial grounds in Boston were required to submit weekly reports of the number of deaths in the city and an annual statement of deaths was compiled and published on the basis of these returns. A new system of registration was established in Boston in the early nineteenth century. In October 1810, the Board of Health divided the city into three districts, within each of which the age, sex, cause of death and other details of all burials was recorded. The information so garnered was printed annually from 1811 in A General Abstract of the Bill of Mortality. The Bills continued to be published until 1849, when the Registrar’s Department was established in the city (Registry Department, Boston, 1893).
2.4 National Surveillance: The United States
Over a quarter of a millennium, local and national disease surveillance in the advanced economies has developed from the comparatively primitive bills of mortality into a highly sophisticated, real-time data gathering machine. This is particularly so in the United States, and so in this section, we examine as a case study the evolution of surveillance systems for communicable diseases in this country.
Background
Thacker and Berkelman (1988) trace the basic elements of disease surveillance in the American colonies back to the mid-eighteenth century. In 1741, the colony of Rhode Island passed an act that required tavern keepers to report the occurrence of contagious diseases among their patrons. Within a few years, the colony passed a law requiring the statutory reporting of smallpox and yellow fever. National monitoring of disease in the United States began in 1850 when mortality statistics, based on the decennial census, were first published for the entire country. By the start of the twentieth century, laws were in place for the notification of selected communicable diseases to local authorities and, in 1914, Public Health Service personnel were appointed to state health departments to telegraph weekly summaries of notifications to the Public Health Service. By the mid-1920s, all states were engaged in national morbidity reporting. The US Communicable Disease Center was established in Atlanta, Georgia, in July 1946. Initially concerned with diseases such as malaria, murine typhus and smallpox, the new institution expanded its interests to include all communicable diseases in the United States. In 1970, the Communicable Disease Center became the Center for Disease Control and, subsequently, the Centers for Disease Control and Prevention (CDC) (Etheridge, 1992).
Morbidity and Mortality Weekly Report (MMWR), 1952–2005
In this subsection, we examine the contents of the principal surveillance publication of CDC, and one of the most familiar journals in the epidemiological world: Morbidity and Mortality Weekly Report. Universally abbreviated as MMWR, it has landed on thousands of desks each week since 1952 – first in paper format and now electronically via the Internet. Published since 1961 by CDC in Atlanta, MMWR contains a mix of current information on the distribution of outbreaks and epidemics around the world, reports on vaccines, protective devices, disease definitions and other developments of epidemiological importance, as well as statistical tables of notifiable diseases in the states and territories of the United States. MMWR is valued for its timeliness and immediacy. Somewhat akin to the headlines of a newspaper, the mixture of reports, notices and summaries contained within MMWR provides a means of tracking headline trends in the contemporary occurrence of communicable diseases of national and international importance.
The MMWR Weekly Data Set
Volume 1, Number 1, of the weekly series of MMWR appeared on Friday 11 January 1952 (Figure 2.14). In the 60 years since that first edition, around 3,100 issues have been published. Cliff, Smallman-Raynor, Haggett, et al. (2009, [link]–[link]) have carried out a content analysis of the first 54 years, 1952–2005 (Vols. 1–54), and the results presented in this subsection are based upon that work. Volumes 1–54 comprise 2,798 issues of MMWR Weekly. In addition to the standard tables of notifiable disease counts in the states and other administrative divisions, these issues contain some 16,300 separate reports, articles, notices, updates and related items that appear under a variety of section headings, including ‘Current Trends’, ‘Brief Reports’, ‘Epidemiologic Notes and Reports’, ‘International Notes’, ‘Special Reports’, ‘Surveillance Summaries’ and ‘Updates’. The topics covered in this class of item, which we refer to for convenience as ‘entries’ in the remainder of the present section, range from ciguatera fish poisoning to diabetic retinopathy, iron deficiency to foetal alcohol syndrome, and dental health to childhood pedestrian deaths during Halloween. And scattered among these entries are the early notices and groundbreaking reports of a half-century-long series of newly emerging infectious diseases. Summary details of these entries are given in Table 2.1. Geographically, the majority were related to domestic US issues (85 percent) and the Americas Region (87 percent) more generally. Epidemiologically, just under two-thirds of allcontributions were associated with sample categories of communicable disease that were drawn primarily from Chapter I (‘Certain Infectious and Parasitic Diseases’, A00–B99) of the ICD-10 list (64 percent), with viral and bacterial agents and their associated diseases accounting for almost 60 percent of the entries.
Table 2.1 Summary details of entries in MMWR Weekly, 1952–2005
Category1 |
Number of entries |
|---|---|
All entries |
16,297 |
Domestic/international |
|
Domestic (U.S.) only |
13,838 |
International (non-U.S.) only |
1,650 |
Combined (domestic & international)/no geographical reference |
809 |
WHO world region |
|
Africa |
291 |
Americas |
14,211 |
Eastern Mediterranean |
184 |
Europe |
514 |
South-East Asia |
80 |
Western Pacific |
208 |
Multiple region/other1 |
809 |
Sample communicable disease groups (ICD-10 code) |
|
Intestinal infectious diseases (A00–A09) |
2,014 |
Tuberculosis (A15–A19) |
244 |
Certain zoonotic bacterial diseases (A20–A28) |
551 |
Other bacterial diseases (A30–A49) |
889 |
Infections with a predominantly sexual mode of transmission (A50–A64) |
394 |
Other spirochaetal diseases (A65–A69) |
44 |
Other diseases caused by chlamydiae (A70–A74) |
262 |
Rickettsioses (A75–A79) |
112 |
Viral diseases of the central nervous system (A80–A89) |
1,282 |
Arthropod-borne viral fevers and viral haemorrhagic fevers (A90–A99) |
505 |
Viral infections characterised by skin and mucous membrane lesions (B00–B09) |
1,284 |
Viral hepatitis (B15–B19) |
495 |
HIV disease (B20–B24) |
397 |
Other viral diseases (B25–B34) |
76 |
Mycoses (B35–B49) |
89 |
Protozoal diseases (B50–B64) |
302 |
Helminthiases (B65–B83) |
188 |
Influenza and pneumonia (J09–J18) |
1,334 |
Severe acute respiratory syndrome (U04) |
28 |
Infectious disease agents |
|
Bacteria |
4,000 |
Helminths |
188 |
Protozoa |
345 |
Rickettsiae |
111 |
Viruses |
5,392 |
Multiple/other |
156 |
Notes:
1 Includes entries with no primary geographical reference.
Global trends
Figure 2.15A plots the annual count of entries in MMWR Weekly for all topics (upper line trace) and sample categories of communicable disease encompassed by ICD-10 codes A00–B99 (lower line trace). In the first three decades, the annual count of entries for all topics waned gradually, from an early peak of > 400 per annum to a low of < 150 per annum in the early 1980s. The number of entries then rose again, reaching > 300 per annum from the late 1990s. The curve for communicable diseases tracks the overall pattern – albeit at a lower level – until the early 1980s. Thereafter, the divergence of the two curves reflects both (i) the establishment of new publications (Recommendations and Reports and Surveillance Summaries) as outlets for communicable-disease related information in the MMWR series and (ii) the widening scope of MMWR Weekly as CDC’s activities expanded beyond communicable diseases; see Etheridge (1992) and Centers for Disease Control and Prevention (1996).
Source: redrawn from Cliff, Smallman-Raynor, Haggett, et al. (2009, Figure 3.8, [link]).
New communicable disease categories
One of the interesting features of the data set is the way in which it picks up newly-emerging diseases over time. The main graphs in Figure 2.16 show a progressive shift in the pattern of publishing activity, with disease categories first included in the 1950s (graph A) and 1960s (graph B) displaying a pronounced reduction in levels of coverage in the pages of MMWR Weekly from the late 1970s. With the retreat of these longer-recognised diseases, the episodic spikes of activity associated with the graphs for the 1970s (graph C) and 1980s–2000s (graph D) flag the early reports of such diseases as Legionnaires’ disease (1976–78), human immunodeficiency virus (HIV) (1985), hantavirus pulmonary syndrome (HPS) (1993) and severe acute respiratory syndrome (SARS) (2003). To these developments can be added the trans-Atlantic extension of West Nile fever, evidenced by the early twenty-first-century resurgence of the curve in Figure 2.16B.
Source: redrawn from Cliff, Smallman-Raynor, Haggett, et al. (2009, Figure 3.9, [link]).
Primary Data Generation
MMWR represents, as we have noted, the principal published face of surveillance for communicable diseases in the United States. It is based on primary data which arrives at CDC in two main ways: (i) from individual physicians and state health departments that undertake real-time reporting of data to CDC; and (ii) reactive field investigations by CDC staff from the Epidemic Intelligence Service (EIS). We consider sources (i) and (ii) in turn. Full accounts appear on the CDC website (www.cdc.gov).
Physician and State Epidemiological Recording
The structure of public health case reporting in the United States is summarised in Figure 2.17. The origins of modern-day reporting through the National Notifiable Diseases Surveillance System (NNDSS) can be traced to 1878 when Congress authorised the US Marine Hospital Service (the forerunner of the Public Health Service) to collect reports on the occurrence of certain communicable diseases from US consuls overseas. As described in Section 3.2, this information was to be used for the implementation of quarantine measures to prevent the introduction of the diseases into the United States. In 1893, Congress expanded the authority for the collection and publication of these overseas reports to include domestic data from states and municipal authorities. Uniformity of disease reporting was subsequently aided by a law, enacted by Congress in 1902, which required the provision of forms for the purposes of data collection, compilation and publication at the national level. A decade later, in 1912, state and territorial health authorities recommended that five diseases should be subject to immediate telegraphic reporting, while an additional 10 diseases should be reported on a monthly basis by letter. The list of notifiable diseases expanded in the following decades such that, by 1928, all states (including the District of Columbia), Hawaii and Puerto Rico were engaged in the national reporting of 29 diseases. The CDC assumed responsibility for the collection and dissemination of nationally notifiable disease data in 1961. Today, the Council of State and Territorial Epidemiologists (CSTE), in conjunction with CDC, makes annual recommendations for diseases to be reported through the NNDSS (Centers for Disease Control and Prevention, 2012d). The list of notifiable diseases for 2012 is given in Table 2.2.
Source: courtesy of S.B. Thacker.
Table 2.2 Nationally notifiable diseases in the United States, 2012
Anthrax |
Plague |
|---|---|
Arboviral neuroinvasive and non-neuroinvasive diseases |
Poliomyelitis, paralytic |
Babesiosis |
Poliovirus infection, nonparalytic |
Botulism |
Psittacosis |
Brucellosis |
Q fever |
Campylobacteriosis |
Rabies, animal and man |
Chancroid |
Rubella (German measles) |
Chlamydia trachomatis infection |
Rubella, congenital syndrome |
Cholera |
Salmonellosis |
Coccidioidomycosis |
SARS-CoV disease |
Cryptosporidiosis |
Shiga toxin-producing Escherichia coli (STEC) |
Cyclosporiasis |
Shigellosis |
Dengue |
Smallpox |
Diphtheria |
Spotted fever rickettsiosis |
Ehrlichiosis/Anaplasmosis |
Streptococcal toxic shock syndrome |
Free-living amoebae, infections caused by |
Streptococcus pneumoniae, invasive disease |
Giardiasis |
Syphilis |
Gonorrhoea |
Tetanus |
Haemophilus influenzae, invasive disease |
Toxic shock syndrome (other than streptococcal) |
Hansen disease (leprosy) |
Trichinellosis (trichinosis) |
Hantavirus pulmonary syndrome |
Tuberculosis |
Hemolytic uremic syndrome, post-diarrheal |
Tularemia |
Hepatitis A, B and C |
Typhoid fever |
HIV infection |
Vancomycin-intermediate Staphylococcus aureus (VISA) |
Influenza-associated hospitalizations |
Vancomycin-resistant Staphylococcus aureus (VRSA) |
Influenza-associated paediatric mortality |
Varicella (morbidity) |
Legionellosis |
Varicella (deaths only) |
Listeriosis |
Vibriosis |
Lyme disease |
Viral hemorrhagic fevers, due to: |
Malaria |
Ebola virus |
Measles |
Marburg virus |
Melioidosis |
Crimean–Congo haemorrhagic fever virus |
Meningococcal disease |
Lassa virus |
Mumps |
Lujo virus |
Novel influenza A virus infections |
New World arenaviruses |
Pertussis |
Yellow fever |
Source: Centers for Disease Control and Prevention (2012d).
National Electronic Disease Surveillance System (NEDSS)
The route by which nationally notifiable disease data arrives at CDC today is via NEDSS, a web-based infrastructure for public health surveillance data exchange between CDC and the 50 states (Centers for Disease Control and Prevention, 2011c). The NEDSS project was launched in 2001 to integrate and replace existing CDC surveillance systems, including the National Electronic Telecommunications System for Surveillance (NETSS, adopted in all states by 1985), HIV/AIDS reporting systems, vaccination programmes and tracking systems for other communicable diseases. NEDSS has been designed, inter alia, partly to feed other CDC data systems, including the following:
WONDER (Wide-ranging OnLine Data for Epidemiologic Research). This is an Internet system that makes CDC information resources available to public health professionals and the public at large. It provides access to a wide array of public health information. Its purposes are (1) to promote information-driven decision making by placing timely, useful facts in the hands of public health practitioners and researchers, and (2) to provide the general public with access to specific and detailed information from CDC (Centers for Disease Control and Prevention, 2012a).
Epi-X (Epidemic Information Exchange). Launched in December 2000, Epi-X is a web-based communications system that facilitates the access and sharing of preliminary health surveillance information by CDC officials, state and local health departments and other public health professionals. Epi-X also has the facility to notify users of the occurrence of health events in real-time. Since inception, the system has been used to post reports on a range of topics, including SARS, West Nile virus and foodborne outbreaks and multi-state food recalls (Centers for Disease Control and Prevention, 2012b).
Epi InfoTM and Epi MapTM. Epi InfoTM is a public domain software package designed to facilitate public health education, disease surveillance and analysis and to encourage collaboration between local, national and international partners, state and territorial epidemiologists, national centres, institutes and government offices, foreign ministries of health and the WHO. It provides questionnaire and database construction, data entry and analysis with epidemiological statistics, graphs and geographical information system (GIS) mapping capability via Epi MapTM (Centers for Disease Control and Prevention, 2012c).
Field Investigations: The US Epidemic Intelligence Service (EIS), 1946–2005
Since inception in the early 1950s, the Epidemic Intelligence Service (EIS) of the CDC has been called on by state, federal, national and international health authorities to assist in the field investigation of thousands of disease outbreaks and other events of public health importance. The history and operations of the EIS are reviewed by Langmuir (1980), Goodman, et al. (1990), Koplan and Thacker (2001) and Thacker, et al. (2001). The EIS Program was established in July 1951 to provide capacity to respond to threats of bioterrorism. Underpinning the initiative, however, was a broader vision to provide a trained cohort of field epidemiologists that would be available at all times for the surveillance and control of diseases in outbreak situations. Since then, some 3,000 EIS Officers have participated in more than 4,000 epidemic assistance investigations in the United States and worldwide (Figure 2.18). In line with the original remit of CDC, the early investigations were largely concerned with outbreaks of communicable diseases. As the responsibilities of CDC have broadened, however, the public health problems addressed by EIS Officers have expanded to include chronic diseases, injuries, drug/vaccine reactions and reproductive, environmental and occupational health issues (Goodman, et al., 1990; Thacker, et al., 2001).
Source: redrawn from Cliff, Smallman-Raynor, Haggett, et al. (2009, Figure 3.16, [link]), originally from Centers for Disease Control and Prevention (2005).
Within the framework of EIS operations, an epidemic assistance investigation (Epi-Aid) is a specific form of investigation that is undertaken by CDC in response to external requests for assistance by states, federal agencies, international organisations and other countries. A request for assistance follows a prescribed administrative mechanism which, if granted, results in the preparation of an initial memorandum (‘Epi-1’) and, following the investigation, a full report on the work undertaken (‘Epi-2’) (Figure 2.19). Although the Epi-1 and Epi-2 documents are for administrative use and have limited circulation, descriptions of investigations of special interest are frequently published in MMWR Weekly and elsewhere in the scientific literature.
Source: Cliff, Smallman-Raynor, Haggett, et al. (2009, Plate 3.4, [link]).
The first 60 years of EIS investigations, 1946–2005, are reviewed by Thacker and colleagues (Stroup and Thacker, 2007; Thacker and Stroup, 2007a, b, 2008; Thacker, et al., 2011). A total of 4,484 EIS investigations were initiated in the period and, while the vast majority of these investigations were based in the United States, EIS activities had a global reach (Figure 2.18). Almost 75 percent of all investigations were associated with infectious diseases, but with chronic diseases, environmental/injury and other/unknown categories accounting for an important share of all requests for assistance since the mid-1960s (Figure 2.20A). Of the communicable disease investigations, viruses and bacteria accounted for the overwhelming majority (82 percent) of causative agents, but with a pronounced growth in investigations concerned with other agents (including mycobacteria, parasites and fungi) over the observation period (Figure 2.20B). The communiable disease investigations are noteworthy for including a number of emerging disease events, including Legionnaires’ disease, Ebola haemorrhagic fever and HIV/AIDS in the period 1976–85, the first occurrence of meat as a vehicle for Listeria monocytogenes, the first documented outbreak caused by Escherichia coli O104:H2 and the identification of apple cider as a vehicle for E. coli O157:H7 in the period 1986–95, and West Nile virus and SARS in the period 1996–2005 (Thacker, et al., 2011).
Source: drawn from data in Thacker, et al. (2011, Table 1, p. S6).
2.5 International Health Cooperation: Before the League of Nations
Proto-Systems: Regional Health Bodies in the Nineteenth Century
By the mid-nineteenth century, a number of maritime powers in the Mediterranean area recognised that the control of epidemic diseases extended beyond quarantine in home ports. Effective measures of disease control required international cooperation and, as described by Goodman (1952, pp. 234–42) and the World Health Organization (1958, [link]–[link]), this formed the basis of regional health bodies in Constantinople, Alexandria, Tangier and Tehran.
Constantinople. The Conseil Supérieur de Santé de Constantinople was formed as an agreement between the Ottoman Empire and European powers in 1839 with a view to regulating the sanitary control of foreign shipping in Ottoman ports. The Conseil oversaw local health offices, distributed throughout the Ottoman Empire, which were responsible for reporting on the health of their areas, the supervision of hygienic measures and the implementation of sanitary regulations received from the Conseil. The Conseil was finally abolished in 1914 with the outbreak of the First World War.
Alexandria. The Conseil Sanitaire Maritime et Quarentenaire d’Egypte, later to become known as the Egyptian Quarantine Board, was established in Egypt in 1843. International regulation of the Board was instituted following the International Sanitary Conference at Venice in 1892 when it was entrusted with the sanitary regime of the Suez Canal. The work of the Board included the port health administration of Alexandria, Suez, Port Said and the Suez Canal, along with the sanitary control of pilgrims returning from Mecca. For the purposes of epidemic intelligence, it was recognised as a regional epidemiological bureau of the Office International d’Hygiène Publique under the International Sanitary Convention of 1926. Although the Board was abolished in 1938, the Egyptian authorities continued to support a Regional Epidemiological Intelligence Bureau in Alexandria, with its functions transferred to the WHO Regional Office for the Eastern Mediterranean in 1949.
Tangier and Teheran. The Conseil Sanitaire de Tangier was established in the 1840s with the intention of limiting the spread of plague, cholera and other epidemic diseases in the Empire of Morocco by pilgrims, although it failed to operate as an effective instrument of international quarantine. The Conseil Sanitaire de Téhéran, established in 1867, was similarly limited in its effectiveness and came to an end with the outbreak of war in 1914 (World Health Organization, 1958).
The Office International d’Hygiène Publique (1907–46)
The International Sanitary Conferences and Conventions
The mid-nineteenth century and the first of the International Sanitary Conferences marked the beginning of a new phase in international health cooperation (Table 2.3), forming a broad platform for the development of international health offices and legislative responses to infectious diseases in the next century (Figure 2.21). The primary objective of the First International Sanitary Conference, opened in Paris in 1851, was for the 12 participating states (all European) to reach agreement on the minimum quarantine requirements for cholera, plague and yellow fever, with a view to facilitating trade and safeguarding public health. Although an international sanitary convention and associated sanitary regulations were formulated, some participants were slow to ratify the convention and it had become inoperative by 1865. Part of this failure lay in the state of medical knowledge regarding cholera and the contradictory views of the delegates regarding the role of quarantine in its control (World Health Organization, 1958).
Table 2.3 The International Sanitary Conferences and Conventions, 1851–1938
Year |
Conference |
Place |
Outcome/convention |
|---|---|---|---|
1851 |
First |
Paris |
Abortive convention |
1859 |
Second |
Paris |
Draft convention only |
1866 |
Third |
Constantinople |
Regulations on Mecca pilgrimages |
1874 |
Fourth |
Vienna |
Proposal for an International Commission on Epidemics |
1881 |
Fifth |
Washington, D.C. |
Recommendation for notification of epidemics through international bureaux |
1885 |
Sixth |
Rome |
Miscellaneous recommendations, primarily concerned with cholera |
1892 |
Seventh |
Venice |
First effective convention, limited to Mecca pilgrimage |
1893 |
Eighth |
Dresden |
General convention on cholera |
1894 |
Ninth |
Paris |
Further convention on cholera and the Mecca pilgrimage (not effective) |
1897 |
Tenth |
Venice |
New convention, including plague |
1903 |
Eleventh |
Paris |
Consolidating convention on cholera and plague |
1912 |
Twelfth |
Paris |
Amended convention, including yellow fever |
1926 |
Thirteenth |
Paris |
Amended convention, including typhus and smallpox |
1938 |
Fourteenth |
Paris |
Amendments to the 1926 convention |
Source: based on Goodman (1952, Appendix 1, [link]).
Further International Sanitary Conferences were held in the second half of the nineteenth century, each centred on the containment of cholera, plague and yellow fever and with their agendas dictated by epidemics of whichever disease was considered to be the most pressing at the time (Table 2.3). The first of the effective International Sanitary Conventions, concerned with the Mecca pilgrimage, came out of the Seventh International Sanitary Conference in 1892. Subsequent conventions evolved to cover cholera (1893), plague (1897), yellow fever (1912) and, into the twentieth century, smallpox (1926) and louse-borne typhus fever (1926); see Table 2.3 and Figure 2.22.
The Office International d’Hygiène Publique (1907–46)
The Office International d’Hygiène Publique (OIHP) was born out of the Eleventh International Sanitary Conference, held in Paris in 1903 (Table 2.3 and Figure 2.21). It was founded under the Rome Agreement on 9 December 1907 and based in Paris. Operating on behalf of participating states, the main purpose of the OIHP was to oversee the international codification of procedures for quarantine and associated surveillance activities. Within this remit, the OIHP served three basic functions (Goodman, 1952):
♦ as the body with responsibility for the revision and administration of the International Sanitary Conventions and associated Conferences;
♦ as a technical commission for the study of epidemic diseases;
♦ as an agency for the rapid exchange of epidemiological information relating to the diseases covered by the International Sanitary Conventions.
The OIHP’s Paris headquarters were established at 195 Boulevard Saint-Germain, from which a regular (monthly) report was circulated to participating states under the title Bulletin Mensuel (Figure 2.23).
![Figure 2.23 Publications and communiqués of the Office International d’Hygiène Publique. (Left) The Bulletin Mensuel de l’Office International d’Hygiène Publique. Article 9 (Annex) of the Rome Agreement of 1903 committed the OIHP to the publication, at least once a month, of a Bulletin. The Bulletin was to include: “(1) Laws and general or local regulations promulgated in the various countries respecting transmissible diseases; (2) Information respecting the spread of infectious diseases; (3) Information respecting the works executed or the measures taken for improving the healthiness of localities; (4) Statistics dealing with public health; (5) Bibliographical notes” [Rome Agreement, 1930, Article 10 (Annex), reproduced in Goodman, 1952, p. 98]. The Bulletin first appeared in 1909 and continued until 1946. (Right) Beginning in November 1928, information collected by the OIHP was summarised in a regular communinqué, published in the Weekly Epidemiological Record of the League of Nations Health Section.](/oxford/fullsizeimage?imageUri=%2F10.1093%2Fmed%2F9780199596614.001.0001%2Fmed_9780199596614_graphic_049-full.gif&uriChapter=%2F10.1093%2Fmed%2F9780199596614.001.0001%2Fmed-9780199596614-chapter-2)
Developments in the aftermath of the First World War ushered in a formal collaboration between the OIHP and the newly-created League of Nations. As described more fully later in this section, the Covenant of the League of Nations included an article relating to international concern for the prevention and control of diseases and, to avoid duplication of activities, consideration was given to the continuation of the OIHP under the authority of the League. The United States objected to this arrangement and, although a relationship was forged in which the Permanent Committee of the OIHP acted as the General Advisory Council of the League of Nations Health Organisation (Figure 2.24), the OIHP and the League’s Health Organisation continued as autonomous international health organisations in Paris and Geneva until the post-war period (World Health Organization, 1958).
Source: © World Health Organization.
One of the principal tasks of the OIHP in the early inter-war years was to oversee the revision of the 1912 Sanitary Convention. The resulting International Sanitary Convention of 1926 increased the number of quarantine diseases to five (by the addition of smallpox and typhus; see Table 2.3 and Figure 2.22), while requiring countries to notify immediately the first cases of plague, cholera and yellow fever and the occurrence of typhus and smallpox in epidemic form. The International Sanitary Conference of 1926 also recommended that certain regional organisations should operate as Regional Bureaux of the OIHP for the provision of epidemiological intelligence. By 1927, arrangements had been made for three such organisations (League of Nations Eastern Bureau at Singapore, Pan American Sanitary Bureau at Washington, D.C. and Sanitary, Maritime and Quarantine Council of Egypt at Alexandria) to operate in this capacity. In turn, the OIHP was required to relay the information received to all countries by weekly telegram or, in urgent instances, immediately. The same information formed the basis of a regular OIHP communiqué that was included in the Weekly Epidemiological Record of the League of Nations Health Section from November 1928 (Figure 2.23), while additional information collected from governments was published in the Annuaire Sanitaire Maritime International (Goodman, 1952; World Health Organization, 1958).
Over the years, the work of the OIHP extended beyond maritime quarantine to include such issues as quarantine regulations for air traffic (an International Sanitary Convention for Aerial Navigation was drawn up in 1932 and came into force in 1935; see Figure 3.39), venereal diseases in seamen, the international standardisation of anti-diphtheritic serum and the control of narcotic drugs. In 1945, the United Nations Relief and Rehabilitation Administration (UNRRA) assumed responsibility for the OIHP’s duties with respect to the International Sanitary Conventions; the OIHP was dissolved by protocols signed on 22 July 1946, with the epidemiological service being incorporated into the Interim Commission of the World Health Organization on 1 January 1947 (World Health Organization, 1958).
The International (Pan American) Sanitary Bureau
The International Sanitary Bureau has the distinction of being the first international health bureau with its own secretariat. Established in 1902 as the regional health bureau for the Americas, the organisation’s subsequent aliases have included the Pan American Sanitary Bureau, the Pan American Sanitary Organization and, today, the familiar Pan American Health Organization (Figure 2.21). By the 1890s, a movement towards inter-American cooperation had begun to take shape and, at the Second International Conference of American Republics (Mexico City, October 1901–January 1902), a recommendation was made that health representatives of the American republics should come together to formulate sanitary regulations and that a permanent executive board should be formed (International Sanitary Bureau) with headquarters at Washington, D.C. A primary function of the Bureau was to oversee inter-American quarantine regulations and to act as a centre for the international exchange of information on epidemic diseases of international importance. Yellow fever was the dominant concern from the outset, although other health matters (smallpox vaccination, malaria and tuberculosis campaigns, national health legislation and other matters) appeared on the agenda in later years (Goodman, 1952; Howard-Jones, 1981).
A reorganisation of the Bureau was undertaken in the years that followed the First World War. With a change of name to the Pan American Sanitary Bureau, the chief activities of the Bureau evolved to include: (i) the collection and transmission of information on outbreaks of epidemic diseases; (ii) preparation of the agenda for the Pan American Sanitary Conferences; (iii) services as a central consultative agency for improving the efficiency of national public health authorities; and (iv) special studies and investigations for combating outbreaks and improving sanitary conditions in member states. As noted earlier, the Bureau was appointed as one of the Regional Bureaux of the OIHP under the International Sanitary Convention of 1926 (Goodman, 1952; Howard-Jones, 1981).
With the establishment of the World Health Organization in the early post-war period, the US advocated that the Bureau should continue to promote regional health programmes in the Americas, whilst also serving as the WHO Regional Office for the Americas (Figure 2.21). Accordingly, it was agreed at the XII Pan American Sanitary Conference at Caracas (1947) that the separate identity of the Bureau should to be maintained, with operations reconstituted under the title of the Pan American Sanitary Organization and, from 1958, the Pan American Health Organization (PAHO). Since that time, the PAHO has continued as a functionally (if not legally) integral part of the WHO’s system of Regional Offices (Figure 2.21), whilst also maintaining its independent identity as a specialist public health organisation for the Western Hemisphere (Howard-Jones, 1981).
2.6 Wireless Technologies: The League of Nations Health Organisation (1923–46)
The establishment of the League of Nations Health Organisation in the aftermath of the First World War (Figure 2.21) ushered in a new era in international health cooperation (League of Nations Health Organisation, 1931; Goodman, 1952, [link]–[link]). Prompted by a series of devastating epidemics of cholera and typhus fever that spread across Eastern Europe with the population upheavals of the time, a provisional Health Committee of the League was formed in Geneva in 1921. The constitution of the Health Organisation was adopted in September 1923 and, over the next two decades, the remit of the Organisation developed to include the establishment of a Malaria Commission (1923) and a Cancer Commission (1923), along with technical commissions on biological standardisation, housing, physical fitness, typhus, leprosy and rural hygiene, among other health-related issues (World Health Organization, 1958).
The Epidemiological Intelligence Service
The first meeting of the Health Committee of the League of Nations took place in August 1921 to consider “the question of organising means of more rapid interchange of epidemiological information” (League of Nations Health Section, 1922d, [link]). At this and subsequent meetings, it was emphasised that epidemiological intelligence work should receive immediate attention and that the most important and pressing work in this field was with regard to the submission of epidemiological information in relation to infectious diseases in Eastern Europe in general and Russia in particular. The need for epidemiological information had been forcibly demonstrated in the course of the work of the League of Nations Epidemic Commission (initially the Typhus Commission) that had been established in April 1920 to tackle the ongoing outbreaks of typhus fever in Poland, Soviet Russia and the Ukraine, Latvia and Greece (Figure 2.21). In response, the Epidemiological Intelligence Service was instituted in the Geneva Health Section and started to prepare reports on the health situation of Eastern Europe in 1921. These reports were first published in 1922 and progressively expanded to include not only Eastern Europe, but also Central Europe and all European countries. Details of the reports included in the Epidemiological Intelligence (E.I.) series and, running in parallel, other Health Section statistical series [Weekly (Epidemiological) Record, R.H.; and Monthly Epidemiological Report, R.E.] are provided by Cliff, et al. (1998, pp. 389–93). We note here that, during the inter-war period, the breadth and geographical reach of the publications evolved to include regular counts of disease-specific morbidity and mortality for a global sample of countries.
The League of Nations’ concern with disease surveillance owes much to Ludwik Rajchman (see Figure 2.25), the first director of the Health Organisation. Rajchman’s vision for the Organisation as a global centre for epidemiological information collection and exchange is highlighted in an unpublished memorandum, dated 19 January 1922:
[N]o institution is undertaking at present the publication of a comprehensive survey of the epidemiological situation of the world…. On the other hand all national health administrations publish periodical, mostly annual reports concerning health conditions in their respective countries. No institution has yet undertaken a comparative study of the information contained in those valuable reports. No institution is taking the initiative of the study of current epidemics affecting the whole world…. It is the duty of the Health Section to fill such gaps…. The Section itself is undertaking the periodical publication of an epidemiological bulletin…and it is hoped that it will be possible for the Section to evolve a scheme which will allow it to become an international clearing house for such information…. It may be stated that the Public Health Services of the world are at present far from being united in a common ‘esprit de corps’ and in an equal realization of the ideas of common service
(Ludwik Rajchman, unpublished memorandum, 19 January 1922, cited in Brown, 2006, [link]).
Sources: (Group photograph) World Health Organization archives; (Rajchman, inset) UNICEF (http://www.unicef.org/about/history/index_leadership_exec_board.html); (Gilbert, inset) The Straits Times, 16 January 1936 (p. 13).
The surveillance function developed in line with this vision. Between 1927, when collaboration between the Office International d’Hygiène Publique and the League of Nations Health Organisation was defined, and 1939 the reach of the Organisation’s Epidemic Intelligence Service expanded to cover 90 percent of the world’s population. As Goodman (1952, [link]) observes:
By the analysis of reports coming to Geneva directly or from the Paris Office and its regional bureaux in Washington, Alexandria, Singapore and Sydney, the Health Organisation could keep a kind of sphygmographic record of the pulse of the world’s epidemics and so keep governments informed of them by cable and wireless and by weekly, monthly, bi-monthly and annual publications.
When surveillance operations began in the early 1920s, the postal service represented the principal mechanism for the submission of epidemiological information from administrations to Geneva. But communications technology was developing rapidly. In October 1923, N.V. Lothian, a Field Epidemiologist in the Health Section of the League of Nations, could assure a meeting of the Section on Vital Statistics of the American Public Health Association that the “question of telegraphing reports to ensure greater promptitude is under discussion” and “that a scheme has been worked out whereby the American weekly summary can be cabled to Geneva by an ingenious code costing us only some 500 francs per year” (Lothian, 1924, p. 289). Just a few years later, the Eastern Bureau of the League of Nations Health Organisation would lead the development of wireless technology as a tool in global disease surveillance. It is to the work of the Eastern Bureau that we now turn.
Expanding Horizons and New Technologies: The Eastern Bureau
While the early work of the League of Nations Health Organisation was directed towards the emergency situation in Eastern Europe – a situation that had begun to wane by 1922 – the Epidemiological Intelligence Service continued to collect and publish data that provided a world view of epidemic diseases of international importance. The relative prevalence of such diseases in Asia prompted the establishment of the Organisation’s Eastern Bureau in Singapore in March 1925 (Figure 2.21). Under the initial directorship of Gilbert E. Brooke (Figure 2.25), the Eastern Bureau provides an example of the early use of wireless communications in international health cooperation and disease surveillance (Manderson, 1995; Yach, 1998).
Scope of Operations
The Council of the League of Nations agreed to the establishment of the Eastern Bureau at their meeting of June 1924. The scope of the Bureau’s operations was defined at the First Meeting of the Advisory Council of the Eastern Bureau, convened in Singapore in early 1925 (Figure 2.25). The “essential task” of the Bureau was to:
collect information on the prevalence of epidemic disease at ports in an area extending from Cape Town to Vladivostock and Alexandria, including Australia; also, to obtain intelligence on ‘infected’ ships to classify the information and to re-telegraph…[the] same in the form of a weekly bulletin, confirmed subsequently by mail by means of a Weekly Fasciculus, which contains also additional information on public health in various districts of the territory (Eastern Bureau of the League of Nations Health Organisation, 1926a, unpaginated).
The area under epidemiological surveillance by the Bureau, occasionally referred to in official publications as the ‘Eastern Arena’, is mapped in Figure 2.26. The vast area extended from approximately 20°E to 150°E of longitude and 40°S to 40°N of latitude and included ports on the East African seaboard, and the Southern and Eastern coast of Asia and Australasia. For administrative purposes, the area was divided into four geographic groups: a Western group (East Coast of Africa and the Asiatic Coast from Egypt to Burma); a Central group (Malaya, Netherlands East Indies and the administrations of Borneo and the Philippine Islands); an Eastern group (Asiatic Coast from Siam to Siberia, including Japan); and a Southern group (Australia, New Zealand, French New Caledonia, Fiji and Honolulu). The logic behind this fourfold division was that maritime communications within each group were mainly self-contained, with connections between the groups being chiefly the concern of larger ports. Beginning with a tentative list of 35 ‘important ports’ that were frequented by foreign trade ships, the number of ports in regular telegraphic communication with the Bureau grew rapidly, to 66 (1926), 135 (1931) and, as illustrated by the dot distribution in Figure 2.26, 147 (1938).
Source: based on League of Nations Health Section (1938, unnumbered figure, p. 583).
Surveillance operations
Figure 2.27 summarises the routine surveillance operations of the Bureau within the Eastern Arena. As the upper boxes in the diagram show, epidemiological information reached the Bureau through three main channels (cf. Figure 3.6):
(A) immediate notification by telegram. All countries were required to submit an immediate telegraphic report to the Bureau on the first appearance of cholera, plague, smallpox, yellow fever or an unusual prevalence of mortality from any other disease in a port frequented by foreign trade ships (designated ‘important ports’). On the basis of the epidemiological information received, the Bureau determined which countries were in direct communication with the infected ports and sent a summary of the situation by telegram to their administrations;
(B) weekly notification by telegram. All countries were required to submit a weekly telegram, to reach the Bureau by no later than Wednesday (midday), summarising the epidemiological situation in the important ports and other territories in the seven-day period up to the preceding Saturday (midnight);
(C) letter by first available post. The weekly telegram in (B) was to be confirmed by a letter, to be sent to the Bureau by the first available post, that contained supplementary information on the epidemiological status of the ports and other territories.
Source: based on information in Eastern Bureau of the League of Nations Health Organisation (1926b, [link]–[link]).
The information collected by the Bureau was to be circulated, as emergency circumstances dictated, in the form of a telegram to concerned countries and, routinely, in the form of a Weekly Bulletin or resumé to all countries in the Eastern Arena and the League of Nations Health Organisation in Geneva. The information so received was to be used by the administrations to inform decisions on how to prevent entry of a given disease by sea and, in later years, by air. As noted in Section 2.5, in addition to these initially prescribed operations, the International Sanitary Convention of 1926 imposed on the Eastern Bureau the additional role of regional bureau to the Office International d’Hygiène Publique. The Convention came into force in 1928 and, from thereon, the Bureau also operated as the Paris Office’s reporting agency in the Far East (Manderson, 1995).
Telecommunications: cable and wireless
When the Eastern Bureau was first established, it was envisaged that the Bureau’s Weekly Bulletin would be communicated to governments and Geneva by way of a telegram, supplemented by additional information in a printed leaflet or Weekly Fasciculus (Figure 2.28). Routine telegraphic communications, however, were a significant financial liability. As the Bureau’s Annual Report for 1925 explained, “The despatch of telegrams is the basic activity of the Bureau and is an item which will not readily admit of retrenchment without unduly stultifying such activity” and, as such, “The cables will always be the chief item of the Bureau’s expenditure” (Eastern Bureau of the League of Nations Health Organisation, 1926b, [link]). The same report recognised that wireless broadcasts would be much more economical, with the Governments of French Indo-China and the Dutch East Indies having offered to broadcast the Bureau’s Weekly Bulletin via the powerful radio transmitters at Saigon (French Indo-China) and Malabar (Dutch East Indies) at no cost. Through these facilities, wireless broadcasting of the Weekly Bulletin began in early April 1925:
The first general return was despatched by the Bureau to Saigon on Thursday April 2nd, in clear [uncoded], and was broadcasted by their powerful wireless installation and has continued to transmit the weekly message in code, ever since, each Friday at 01:30 G.M.T. on a wave-length of 20,800 metres, and the message is picked-up by Paris and telegraphed to Geneva
(Eastern Bureau of the League of Nations Health Organisation, 1926b, [link]).
Source: World Health Organization archives.
But wireless transmission of the Weekly Bulletin was not without its difficulties:
Most unfortunately the atmospherics of the East would appear to be indifferently good, and the messages can only be picked up by Japan, British North Borneo, and Bandong. The matter is being considered by the Bureau with a view to possible extension of the wireless messages. Were a large number of administrations of the Arena able to get the broadcast, much expense would be saved by the Bureau
(Eastern Bureau of the League of Nations Health Organisation, 1926b, [link]).
Throughout 1926, improvements in the wireless reception of the Weekly Bulletin were pursued, with increasing numbers of stations being able to pick up the Saigon and Malabar broadcasts. In January 1926, Noumea (New Caledonia) confirmed the establishment of a weekly connection with Saigon; Hong Kong followed suit in February, along with India (March), Ceylon (March), Shanghai (June), Australia (June), Fiji (August), Manila (September), Djibouti (September) and Rabaul on the New Britain Archipelago (October) (Eastern Bureau of the League of Nations Health Organisation, 1927). By 1927, the Director of the Eastern Bureau could note that:
The development of our wireless service has been satisfactory. Its network has become denser and has greatly extended through the rebroadcast by new stations of our weekly wireless bulletin. We consider it a sound policy to use powerful stations with wide range of action for the broadcast of our bulletin in code, and to leave to stations of less range the broadcast of the bulletin in clear intended for shipping at sea
(Eastern Bureau of the League of Nations Health Organisation, 1928, [link]).
A total of 30 health administrations in the Eastern Arena were able to pick up the weekly wireless transmission in 1929 and, through the 1930s, a fully functional broadcast system for the Weekly Bulletin became established (Figure 2.29). As hostilities in Europe and Asia intensified, however, there was a decline in the regularity and quality of information being remitted to the Bureau, while wireless broadcasts became impossible. French Indo-China halted communications with Singapore in early 1940, while similar developments in relation to India and other British colonies resulted in the suspension of the Bureau’s operations at the end of 1941.
Source: redrawn from Eastern Bureau of the League of Nations Health Organisation (1939, unnumbered figure, between [link]–[link]).
2.7 Wireless to Internet: The World Health Organization (1946–)
Histories of the origin and development of the World Health Organization (WHO) are provided by Goodman (1952, [link]–233) and World Health Organization (1958, 1968, 2008a). The establishment of a specialised health agency within the United Nations was first proposed by the Brazilian and Chinese delegates at the United Nations Conference on International Organization held in San Francisco (April–June 1945). The Constitution of the WHO was drafted and agreed at an International Health Conference held in New York (June–July 1946) and came into force on 7 April 1948. In preparation for the establishment of the permanent WHO, an Interim Commission was appointed to continue and unify the epidemiological functions of the League of Nations Health Organisation (October 1946), the Health Division of the United Nations Relief and Rehabilitation Administration (December 1946) and the Office International d’Hygiène Publique (January 1947). The First World Health Assembly (June 1948) resolved that the Interim Commission should cease to exist at midnight on 31 August 1948, with the functions of the Commission passing to the WHO in Geneva on 1 September 1948 (Figure 2.30).
Sources: © World Health Organization/Tibor Farkas and (inset) the authors.
Articles 63–65 of the Constitution of the WHO (World Health Organization, 2006) laid down that:
Article 63: Each Member [State] shall communicate promptly to the Organization important laws, regulations, official reports and statistics pertaining to health which have been published by the State concerned;
Article 64: Each Member shall provide statistical and epidemiological reports in a manner to be determined by the Health Assembly; and
Article 65: Each Member shall transmit upon the request of the Board such additional information pertaining to health as may be practicable.
Chapter XI of the Constitution determined that activities should be decentralised along regional lines, with the First World Health Assembly agreeing to the delineation of six world regions: Africa, Americas, Eastern Mediterranean, Europe, South-East Asia and Western Pacific (Figure 2.21). The six Regional Offices had come into being by 1952, with the long-established Pan American Sanitary Bureau (Section 2.5) assuming the role of the Office for the Americas. This regional structure has continued through to the present day (Figure 2.31).
Epidemiological Intelligence and Surveillance, 1940s–1970s
The inheritance of the newly-created WHO included responsibility for international epidemic control in terms of: (i) quarantine and the International Sanitary Conventions; and (ii) epidemic intelligence and epidemiological services. One of the first major tasks of the WHO was to revise and reform the existing International Sanitary Conventions (Table 2.3) and these came into force under the new title of the International Sanitary Regulations in 1952. Further details are provided in Section 3.2, but we note here that the 1952 Regulations represented a synthesis of existing Conventions dealing with maritime, land and air traffic in relation to a total of six quarantine diseases (Figure 2.22). The Regulations continued to require national health administrations to notify the WHO by telegram (or, in some instances, airmail) of the appearance of quarantinable diseases in their territories. Information received under the Regulations was collated by the four WHO quarantine and information services (Geneva, Singapore, Washington, D.C. and Alexandria), with urgent information distributed worldwide by a system of radio bulletins (Figure 2.32). The radio bulletins, in turn, were confirmed via weekly publications. The Weekly Epidemiological Record formed the main WHO publication for this purpose, containing notifications of quarantinable diseases, information on international sanitary legislation and notes on the incidence of non-quarantinable diseases whenever their prevalence became of international importance. In 1961, the functions of the WHO Epidemiological Intelligence Stations at Alexandria, Singapore and Washington were transferred to WHO HQ at Geneva and, from that time, administration of the International Sanitary Regulations was totally centralised with direct communications between the various national health administrations and Geneva (World Health Organization, 1958, 1968).
Source: Goodman (1952, Figure 36, [link]).
Increasingly, the WHO’s work extended beyond surveillance functions for the quarantine diseases to include other communicable diseases through various programmes and an expanding network of collaborators in the field and laboratories. Important developments included the establishment in 1958 of a WHO study group to advise on the collection of immunological information through immunological and haematological surveys. WHO serum reference banks were established and antibody studies of a range of diseases (including poliomyelitis, measles, rubella, influenza, arbovirus infections, rickettsial infections, pertussis, typhoid and diphtheria, among other diseases) were undertaken in the 1960s in Africa, the Americas, Asia and Europe. Alongside diseases for which surveillance activities were already in place (including cholera, influenza, malaria, smallpox and tuberculosis), surveillance of a range of other diseases was initiated, including: dengue haemorrhagic fever (started in 1964), salmonellosis (started in 1965) and, in cooperation with the Food and Agriculture Organization (FAO) and the World Organisation for Animal Health (OIE), rabies.
In the late 1960s, the WHO replaced ‘epidemiological intelligence’ with ‘epidemiological surveillance’ as an approach to disease control. The new approach had grown out of improved epidemio logical methods (including data processing and analysis, laboratory and field studies) and was defined as
The exercise of continuous scrutiny of and watchfulness over the distribution and spread of infections and factors related thereto, of sufficient accuracy and completeness to be pertinent to effective control
With this development, the Unit of Quarantine was merged with the Unit of Epidemiological Surveillance in 1968 and, by 1970, the programme was referred to as Epidemiological Surveillance. This strategy was adopted as a means of moving away from the concept that disease prevention and control could only be achieved through the application of quarantine measures. As a consequence of this development, the existing International Sanitary Regulations (1952) were revised and adopted as the International Health Regulations in 1969 (Figure 2.22). Accordingly, the Committee on International Quarantine changed its name to the Committee on International Surveillance of Communicable Diseases. Information collected by the Epidemiological Surveillance programme was disseminated daily through the WHO epidemiological radiotelegraphic (later telex) bulletin and the Weekly Epidemiological Report. Additionally, the Epidemiological Surveillance programme placed emphasis on the strengthening of national surveillance; training of epidemiologists in Member States in surveillance methods was provided, along with the availability of technicians and allied health personnel to observe and report on outbreaks. Inter-country centres for epidemiological surveillance were established in the WHO Africa (Abidjan, Nairobi and Brazzaville in 1974) and Americas (Caribbean Epidemiology Centre, Port-of-Spain, in 1975) Regions. Technical manuals were prepared for the surveillance of four diseases under the international health regulations (cholera, plague, smallpox and yellow fever) and five other diseases (influenza, louse-borne typhus fever, louse-borne relapsing fever, malaria and paralytic poliomyelitis), while a general guide on disease surveillance was prepared in 1975. This same period witnessed great strides in disease prevention and control through the eradication of smallpox (see Section 5.2) and, from 1973, the implementation of the Expanded Programme on Immunization (see Section 4.4) (World Health Organization, 2008a).
With the advent of computer technology, a computer was installed at the WHO HQ in the mid-1960s and computerisation of statistical work was undertaken. Data received by the WHO from Member States since 1950 was stored in digital format. Computers, in turn, permitted information processing and the development of epidemiological models in relation to such diseases as typhoid, cholera, tetanus and diphtheria (Uemura, 1988).
International Patterns of Communicable Disease Surveillance, 1923–83
What was the practical reality on the ground of all this international disease surveillance activity in the six decades from the formation of the League of Nations Health Organisation? Which communicable diseases were recorded by which countries? To address these questions, Cliff, Smallman-Raynor, Haggett, et al. (2009, [link]–[link]) have used three main League of Nations/WHO sources of international morbidity and mortality data (Annual Epidemiological Report, 1923–38; Annual Epidemiological and Vital Statistics, 1939–61; and World Health Statistics Annual, 1962–83) to construct a worldwide (year × disease × country) matrix of diseases subject/not subject to globally documented surveillance, 1923–83. While details of the data matrix are given by Cliff and colleagues, we note here that it is based on two categories of data:
(1) notifiable diseases (1923–58). For the period 1923–58, Annual Epidemiological Report and its successor publication, Annual Epidemiological and Vital Statistics, included a chart or table which recorded in matrix format (diseases' countries) which diseases were notifiable in each region of the world. Figure 2.33 shows a detail of one such chart for 1930;
(2) reported diseases (1959–83). Between 1959 and 1983, the matrices of notifiable diseases were not published, but equivalent matrices of reported diseases by country can be constructed from the raw returns of recorded (non-zero) mortality and morbidity published in later issues of Annual Epidemiological and Vital Statistics and its successor publication, World Health Statistics Annual.
Source: League of Nations Health Organisation (1932, [link]–[link], detail).
For 29 sample years (1923–37, 1946, 1949–55, 1958, 1963, 1965, 1970, 1975, 1980 and 1983; see Cliff, et al., 2009, [link]–[link]), data types (1) and (2) yielded a 29 (years) × 123 (communicable diseases) × 193 (Member States) 1/0 matrix of communicable diseases subject/not subject to globally documented surveillance. The geographical sample included 100 percent of WHO Member States (2008 status), distributed according to the six standard WHO regions in Figure 2.31. The 123 sample communicable diseases, categorised according to Chapter I (Certain Infectious and Parasitic Diseases, A00–B99) of ICD-10, are given in Appendix 2.1.
Global Trends
Figure 2.34A plots, by annual period, the number of sample communicable disease categories (lower line trace) and the associated number of WHO Member States (upper line trace) for which surveillance activities were documented in the League of Nations/WHO data set. As the graph shows, the number of disease categories under surveillance by WHO Member States varied between 40–60 per annum for much of the observation period, but with a rapid increase to > 80 in the early 1980s. The same interval was associated with a steady and progressive increase in the number of WHO Member States for which surveillance activities for the sample disease categories were documented, from 85 (44 percent of WHO Member States) at the start of the observation period to a peak of 160 (83 percent of WHO Member States) in the early 1970s.
Source: redrawn from Cliff, Smallman-Raynor, Haggett, et al. (2009, Figures 3.2 and 3.3A, [link], [link]).
The time series of diseases in Figure 2.34A is based on the count of disease categories for which surveillance activities were documented across the set of Member States. It is important to recognise that not all countries undertook surveillance for all the diseases, and Member States varied in terms of the number of disease categories under surveillance in any given year. To capture this variability, the heavy line trace in Figure 2.34B plots, by annual period, the median number of sample communicable disease categories for which surveillance activities were documented by Member States, along with the inter-quartile range (Q1 and Q3; shaded envelope) and maximum and minimum (broken line traces) counts. As the graph shows, the first four decades of the observation period were associated with a steady increase in the median number of disease categories, rising from 15 (1923) to 30 (1963), but with a sharp reduction thereafter. As judged by the inter-quartile range, many WHO Member States approximated this general surveillance pattern.
Emerging Diseases in the Global Surveillance Record
Of the 123 sample disease categories under consideration, 53 were included in the League of Nations/WHO records for the 1920s. For the remaining 70, Figure 2.35 shows the number first included in the surveillance records by decadal period, 1930s,…, 1980s; the associated diseases are given in Table 2.4. While ‘new’ disease categories were added to the surveillance records at various stages during the six-decade interval, some 25 percent of the 123 categories included in the analysis were recorded for the first time in the 1980s. As a rule, this latter development reflected the extension of ICD recording classes, graphed in Figure 2.4, to include ‘other’, ‘unspecified’ and ‘not elsewhere classified’ disease categories associated with a broad range of bacterial, fungal, helminthic, protozoal and viral diseases.
Source: redrawn from Cliff, Smallman-Raynor, Haggett, et al. (2009, Figure 3.5, [link]).
Table 2.4 League of Nations/WHO: communicable disease categories included for the first time in global surveillance records, 1930s–80s
Decade of first inclusion |
Disease category (ICD-10 code) |
|---|---|
1930s |
Shigellosis (A03); amoebiasis (A06); tularemia (A21); rat-bite fevers (A25); rhinoscleroma (A48); other spirochaetal infections (A69); psittacosis (A70); foot-and-mouth disease (B08); coccidioidomycosis (B38); other fluke infections (B66); other helminthiases (B83). |
1940s |
Bartonellosis (A44); gas gangrene (A48); colibacillosis (A49); chlamydial lymphogranuloma (venereum) (A55); typhus, endemic (murine typhus) (A75); Q fever (A78); trench fever (A79); unspecified viral encephalitis (A86); other arthropod-borne viral fevers, not elsewhere classified (A93); zoster (B02); viral hepatitis (B15–B19); infectious mononucleosis (B27); Chagas’ disease (B57); ascariasis (B77). |
1950s |
None. |
1960s |
Other tetanus (A35); congenital syphilis (A50); early syphilis (A51); late syphilis (A52); other and unspecified syphilis (A53); relapsing fever, tick-borne (A68); Brill’s disease (A75); unspecified malaria (B54). |
1970s |
Other zoonotic bacterial diseases, not elsewhere classified (A28); infection due to other mycobacteria (A31); Boutonneuse fever (A77); tick-borne viral encephalitis (A84); acute hepatitis B (B16); other acute viral hepatitis (B17); chronic viral hepatitis (B18); other and unspecified infectious diseases (B99). |
1980s |
Other salmonella infections (A02); other bacterial intestinal infections (A04); other bacterial foodborne intoxications (A05); other protozoal intestinal diseases (A07); viral and other specified intestinal infections (A08); trichomoniasis (A59); unspecified sexually transmitted disease (A64); atypical virus infections of central nervous system (A81); mosquito-borne viral encephalitis (A83); viral meningitis (A87); other viral infections of central nervous system, not elsewhere classified (A88); unspecified viral infection of central nervous system (A89); sandfly fever (A93); unspecified arthropod-borne viral fever (A94); arenaviral haemorrhagic fever (A96); other viral haemorrhagic fevers, not elsewhere classified (A98); unspecified viral haemorrhagic fever (A99); viral conjunctivitis (B30); candidiasis (B37); histoplasmosis (B39); blastomycosis (B40); other mycoses, not elsewhere classified (B48); toxoplasmosis (B58); other predominantly sexually transmitted diseases, not elsewhere classified (B63); unspecified protozoal disease (B64); other cestode infections (B71); other intestinal helminthiases, not elsewhere classified (B81); unspecified intestinal parasitism (B82); unspecified parasitic disease (B89). |
World Regional Disease Patterns
One important geographical question that can be asked of the data set relates to the regional specificity of disease surveillance activities. More particularly, is it possible to identify distinctive regional concentrations of disease categories for which surveillance was undertaken and, if so, did these regional concentrations change over time? Table 2.5 is based on Cliff, Smallman-Raynor, Haggett, et al. (2009, [link]–[link]) and identifies those communicable disease categories for which each of the six WHO Regions displayed a particular concentration of surveillance activities, relative to the global pattern, in a given decadal period (1920s,…, 1980s). Up to five diseases with the highest regional concentrations of surveillance activities (rank 1 = highest concentration) are shown.
Table 2.5 Regional specificity of communicable disease categories most commonly subject to monitoring in WHO member states, 1920s–1980s
World region |
Decade |
Disease1 |
||||
|---|---|---|---|---|---|---|
Rank 1 |
Rank 2 |
Rank 3 |
Rank 4 |
Rank 5 |
||
Africa |
1920s |
African trypanosomiasis (B56) |
Schistosomiasis (B65) |
Brucellosis (A23) |
--- |
--- |
1930s |
African trypanosomiasis (B56) |
Yaws (A66) |
--- |
--- |
--- |
|
1940s |
African trypanosomiasis (B56) |
Yaws (A66) |
Relapsing fever, unspecified (A68) |
Schistosomiasis (B65) |
--- |
|
1950s |
African trypanosomiasis (B56) |
Leishmaniasis (B55) |
--- |
--- |
--- |
|
1960s |
African trypanosomiasis (B56) |
Relapsing fever, tick-borne (A68) |
Smallpox (B03) |
Schistosomiasis (B65) |
Leishmaniasis (B55) |
|
1970s |
Tick-borne viral encephalitis (A84) |
Rubella (B06) |
Chronic viral hepatitis (B18) |
Relapsing fever, tick-borne (A68) |
Pediculosis (B85) |
|
1980s |
Unspecified viral infection of the CNS (A89) |
Unspecified arthropod-borne viral fever (A94) |
Coccidioidomycosis (B38) |
Histoplasmosis (B39) |
African trypanosomiasis (B56) |
|
Americas |
1920s |
Filariasis (B74) |
Spotted fever (A77) |
Dengue fever (A90) |
Syphilis (A50–A53) |
Leptospirosis (A27) |
1930s |
Rat-bite fevers (A25) |
Coccidioidomycosis (B38) |
Spotted fever (A77) |
Pediculosis (B85) |
Tularemeia (A21) |
|
1940s |
Rat-bite fevers (A25) |
Gas gangrene (A48) |
Colibacillosis (A49) |
Q fever (A78) |
Coccidioidomycosis (B38) |
|
1950s |
Spotted fever (A77) |
Q fever (A78) |
Coccidioidomycosis (B38) |
Other fluke infections (B66) |
Ascariasis (B77) |
|
1960s |
Spotted fever (A77) |
Granuloma inguinale (A58) |
Other spirochaetal infections (A69) |
Unspecified mycosis (B49) |
Yellow fever (A95) |
|
1970s |
Diarrhoea and gastroenteritis (A09) |
Infection due to other mycobacteria (A31) |
Spotted fever (A77) |
Other and unspecified infectious diseases (B99) |
Yellow fever (A95) |
|
1980s |
Yellow fever (A95) |
Erysipelas (A46) |
Dengue fever (A90) |
Plague (A20) |
Viral hepatitis (B15–B19) |
|
Eastern Mediterranean |
1920s |
Dermatophytosis (B35) |
--- |
--- |
--- |
--- |
1930s |
--- |
--- |
--- |
--- |
--- |
|
1940s |
Schistosomiasis (B65) |
Echinococcosis (B67) |
--- |
--- |
--- |
|
1950s |
Pediculosis (B85) |
Echinococcosis (B67) |
--- |
--- |
--- |
|
1960s |
Congenital syphilis (A50) |
Cholera (A00) |
--- |
--- |
--- |
|
1970s |
Typhus, endemic (murine typhus) (A75) |
Acute hepatitis B (B16) |
Other acute viral hepatitis (B17) |
Pediculosis (B85) |
Malaria (B50–B54) |
|
1980s |
Unspecified protozoal disease (B64) |
Blastomycosis (B40) |
Leishmaniasis (B55) |
Other intestinal helminthiases, NEC (B81) |
Other fluke infections (B66) |
|
Europe |
1920s |
Trench fever (A79) |
Unspecified mycosis (B49) |
Pediculosis (B85) |
Scabies (B86) |
Other viral diseases, NEC (B33) |
1930s |
Other specified bacterial diseases (A48) |
Trench fever (A79) |
Other viral diseases, NEC (B33) |
Leptospirosis (A27) |
Glanders (A24) |
|
1940s |
Other specified bacterial diseases (A48) |
Other rickettsioses (A79) |
Trench fever (A79) |
Sandfly fever (A93) |
Infectious mononucleosis (B27) |
|
1950s |
Trench fever (A79) |
Other arthropod-borne diseases, NEC (A93) |
Botulism (A05) |
Tularemia (A21) |
Infectious mononucleosis (B27) |
|
1960s |
Late syphilis (A52) |
Brill’s disease (A75) |
Q fever (A78) |
Tularemia (A21) |
Echinococcosis (B67) |
|
1970s |
Other zoonotic bacterial diseases, NEC (A28) |
Brill’s disease (A75) |
Boutonneuse fever (A77) |
Tularemia (A21) |
Psittacosis (A70) |
|
1980s |
Brill’s disease (A75) |
Infection due to other mycobacteria (A31) |
Unspecified sexually transmitted disease (A64) |
Q fever (A78) |
Zoster (B02) |
|
South-East Asia |
1920s |
Leishmaniasis (B55) |
Diarrhoea and gastroenteritis (A09) |
--- |
--- |
--- |
1930s |
Diarrhoea and gastroenteritis (A09) |
Filariasis (B74) |
--- |
--- |
--- |
|
1940s |
--- |
--- |
--- |
--- |
--- |
|
1950s |
--- |
--- |
--- |
--- |
--- |
|
1960s |
Cholera (A00) |
Plague (A20) |
--- |
--- |
--- |
|
1970s |
Smallpox (B03) |
--- |
--- |
--- |
--- |
|
1980s |
Relapsing fever, tickborne (A68) |
Atypical virus infections of the CNS (A81) |
Arenaviral haemorrhagic fever (A96) |
Other mycoses, NEC (B48) |
Unspecified viral haemorrhagic fever (A99) |
|
Western Pacific |
1920s |
Echinococcosis (B67) |
Dermatophytosis (B35) |
Botulism (A05) |
Actinomycosis (A42) |
Granuloma inguinale (A58) |
1930s |
Other heminthiases (B83) |
Echinococcosis (B67) |
Other fl uke infections (B66) |
Schistosomiasis (B65) |
Other septicaemia (A41) |
|
1940s |
Chlamydial lymphogranuloma (venereum) (A55) |
Echinococcosis (B67) |
Diarrhoea and gastroenteritis (A09) |
Viral hepatitis (B15–B19) |
Filariasis (B74) |
|
1950s |
Diarrhoea and gastroenteritis (A09) |
Filariasis (B74) |
Rubella (B06) |
Dengue fever (A90) |
Viral hepatitis (B15–B19) |
|
1960s |
Diarrhoea and gastroenteritis (A09) |
Cholera (A00) |
Yaws (A66) |
Dengue fever (A90) |
Filariasis (B74) |
|
1970s |
Other acute viral hepatitis (B17) |
Leptospirosis (A27) |
Syphilis (A50–A53) |
Unspecified viral encephalitis (A86) |
Gonococcal infection (A54) |
|
1980s |
Unspecified parasitic disease (B89) |
Mosquito-borne viral encephalitis (A83) |
Arenaviral haemorrhagic fever (A96) |
Candidiasis (B37) |
Other acute viral hepatitis (B17) |
Notes:
1 Up to five disease categories with a marked regional concentration of surveillance activities are shown (rank 1 = highest concentration); the associated three-character ICD-10 codes are given in parentheses. CNS = central nervous system. NEC = not elsewhere classified.
The table identifies a series of distinctive marker diseases for several of the world regions. In Africa, for example, African trypanosomiasis (1920s–80s), schistosomiasis (1920s–60s) and relapsing fever (1940s–70s) feature in the list in three or more decadal periods. Likewise, spotted fever (1920s–70s), coccidioidomycosis (1930s–50s) and yellow fever (1960s–80s) are prominent in the Americas, as are trench fever (1920s–50s), tularemia (1950s–70s) and Brill’s disease (1960s–80s) in Europe and echinococcosis (1920s–40s) and diarrhoea and gastroenteritis (1940s–60s) in the Western Pacific. Only in relatively rare instances, however, does a single disease category remain important throughout the entire observation period. Rather, the general tendency is for a disease category newly to enter the list for a given region, remain for one, two or three decades, to be succeeded by other disease categories in subsequent periods.
A further feature of Table 2.5 is the way in which documented surveillance activities have evolved as both surveillance capacity and the number of recognised disease categories has expanded over time. During the 1930s and 1940s, Cliff, Smallman-Raynor, Haggett, et al. (2009) observe that the regional lead in the monitoring of ‘new’ disease categories was taken by the Americas (coccidioidomycosis, colibacillosis, gas gangrene, Q fever and rat-bite fevers), Europe (infectious mononucleosis) and the Western Pacific (other helminthiases, chlamydial lymphogranuloma and viral hepatitis). From the 1960s, the geographical focus of monitoring activities for newly-defined disease categories evolved to include Africa, Eastern Mediterranean and South-East Asia. Especially prominent in this latter development were a range of unspecified and atypical arthropod-borne viral fevers and infections of the CNS, viral haemorrhagic fevers, bacterial, fungal, helminthic and protozoal infections that were first included in the League of Nations/WHO surveillance records in the 1980s.
Developments in Programme-Oriented Surveillance
From the mid-1980s, the character of international recording of communicable disease morbidity and mortality changed fundamentally from systematic time period × disease × country surveillance of a large basket of infectious conditions to a targeted surveillance related to international health programmes. And so, in 1982, the WHO programmes on Health Statistics and Epidemiological Surveillance were merged to form the Health Situation and Trend Assessment Programme. This new programme placed emphasis on a target-oriented approach to information, with priority given to only the most essential information for the improvement of health systems (Uemura, 1988). This approach, built around vaccine-controllable and potentially globally-eradicable diseases, had been presaged by the Smallpox Eradication Programme in the 1960s and 1970s and was followed by the Expanded Programme on Immunization from 1974 and the Global Polio Eradication Initiative from 1988. Here, we examine aspects of programme-oriented surveillance in relation to the global smallpox and poliomyelitis eradication campaigns. Overviews of the eradication campaigns are provided in Sections 5.2 (smallpox) and 5.3 (poliomyelitis).
Active Search Operations: The Intensified Smallpox Eradication Programme (1967–77)
As described in Section 5.2, the Nineteenth World Health Assembly committed the WHO to an intensified 10-year global Smallpox Eradication Programme which was launched in 1967. The eradication campaign started with mass vaccination, but rapidly recognised the importance of selective control. As Fenner, et al. (1988, pp. 473–4) explain, the issue of smallpox surveillance at the national or international levels had received little attention prior to the onset of the eradication campaign and, although the disease was subject to reporting under international quarantine agreements (Figure 2.22), endemic countries lacked formal programmes to investigate and contain outbreaks. From the outset of the campaign, however, the number of reported cases of smallpox and the number of endemic countries became the key indicators of the campaign’s progress:
The primary objective of the smallpox programme is the eradication of this disease. Surveillance is thus an essential component of the programme since the term ‘eradication’ implies that the number of indigenous cases of smallpox reach ‘0’…
(WHO Handbook, cited in Fenner, et al., 1988, p. 474).
Fully satisfactory networks of notification took 1–2 years to develop. Initially, reliance was placed on surveillance of those attending health units. From September 1973, however, the nature of both surveillance and containment began to change. At this stage, surveillance-containment operations and mass vaccination had halted transmission of smallpox in all but five countries (Bangladesh, Ethiopia, India, Nepal and Pakistan). In the summer of 1973, WHO devised an intensified system of case detection and (later) containment, applied first in India and, subsequently in Pakistan (late 1973), Bangladesh (early 1975), Ethiopia (late 1975) and Somalia (mid 1977). This intensified system rested with the more complete and prompt detection of outbreaks and involved supplementing the existing notification system by engaging health staff from other programmes in national village-by-village and house-to-house searches. Echoing aspects of the local detective work undertaken by searchers employed in the compilation of the London Bills centuries earlier (Section 2.3), the smallpox searches involved many tens of thousands of workers and were conducted at different intervals in different areas (typically, every 4–8 weeks in endemic areas and every 2–3 months in non-endemic areas). When a suspected smallpox case was found, the search worker notified the supervisor or nearest health unit so that containment staff could move in. Searches were accompanied by an intensive publicity campaign, and rewards were offered to the populace for information on cases. Special search programmes were implemented for areas that were difficult to access (Fenner, et al., 1988).
Active search operations in India
Active search operations for smallpox in India are described by Basu, et al. (1979, [link]–[link]). The first village-to-village search for smallpox cases was undertaken in West Bengal in September 1973 and, in subsequent months, in the highly endemic states of Bihar, Madhya Pradesh and Uttar Pradesh. The search operations were later extended beyond the four endemic states to include 11 low incidence states in November–December 1973 and 16 smallpox-free states from December 1973. Search operations continued until the last all-India search in October–November 1976 (Figure 2.36). Searches involved the questioning of households and people in prominent places (e.g. markets, tea shops and schools) and positions (e.g. village leaders, teachers and postmen) for information on cases of rash with fever; smallpox recognition cards were also shown to illustrate the disease. All told, these operations involved a total of 463 searches and 11.27 million village visits between September 1973 and November 1976. The active search operations yielded evidence of 20,835 outbreaks and 77,704 smallpox cases in the entire search period to November 1976; the last detected smallpox case was discharged from hospital in July 1975 and India was declared free of smallpox by an International Commission in April 1977 (Basu, et al., 1979); see Figure 2.37.
Source: redrawn from Basu, et al. (1979, Figure 7.10, [link]).
Syndromic Surveillance: The Global Polio Eradication Initiative (1988–)
Methods of syndromic surveillance are frequently adopted where early detection of a disease event is considered a high priority. Syndromic surveillance focuses on the monitoring of health indicators that are available prior to the confirmation of diagnosis or laboratory confirmation of infection. The information is in near-real time and is often available sooner than a laboratory test can be completed.
Sensitive syndromic surveillance for acute flaccid paralysis (AFP) has formed a major strand of the Global Polio Eradication Initiative (Hull, et al., 1997), to which the WHO was committed by the Forty-first World Health Assembly in May 1988 (Section 5.3). Acute flaccid paralysis is the principal clinical syndrome of paralytic poliomyelitis and is characterised by paralysis, muscle flaccidity and sudden onset. Although AFP is a feature of all cases of paralytic poliomyelitis, the syndrome has a number of aetiologies. These range from other neurotropic viruses to trauma and chemical exposure. Surveillance for AFP is considered the gold standard for detecting cases of poliomyelitis and involves four steps: (i) finding and reporting children with AFP; (ii) transporting stool samples for analysis; (iii) isolating and identifying poliovirus in the laboratory; and (iv) mapping the virus to determine the origin of the virus strain.
The syndromic surveillance strategy adopted by the Global Polio Eradication Initiative requires the immediate reporting and rapid laboratory-based investigation of all cases of AFP in children aged < 15 years. This serves in the detection of typical and atypical cases of poliomyelitis due to both wild and vaccine-derived strains of poliovirus. Laboratory-based investigation of samples is coordinated through the Global Polio Laboratory Network, a global and interdependent network of laboratories that was formalised in 1992–93 (Figure 2.38). AFP surveillance provides a basis for assessment of the quality of disease surveillance for certification purposes (Table 2.6). Molecular epidemiologic methods have enhanced the precision and reliability of laboratory-based poliomyelitis surveillance, allowing wild viruses to be classified into genetic families from which inferences on the geographical source of isolates can be drawn (Cochi, et al., 1997; World Health Organization, 1998b).
Source: redrawn from Cliff, Smallman-Raynor, Haggett, et al. (2009, Figure 11.23, p. 664), originally from World Health Organization (2000a, Map 1, [link]).
Table 2.6. Principal performance indicators for acute flaccid paralysis (AFP) surveillance
Criterion |
Performance measure |
|---|---|
Completeness of reporting |
≥ 80 percent of expected routine (weekly or monthly) AFP surveillance reports should be received on time, including zero reports where no AFP cases are seen. The distribution of reporting sites should be representative of the geography and demography of the country. |
Sensitivity of surveillance |
≥ 1 case of non-poliomyelitis AFP should be detected annually per 100,000 population aged <15 years. |
Completeness of case investigation |
All AFP cases should have a full clinical and virological investigation with ≥ 80 percent of AFP cases having adequate stool specimens collected for enterovirus studies. (Adequate stool specimens are defined as: two specimens of sufficient quantity for laboratory analysis, collected at least 24 hours apart, within 14 days after the onset of paralysis, and arriving in the laboratory by reverse cold chain and with proper documentation.) |
Completeness of follow-up |
≥ 80 percent of AFP cases should have a follow-up examination for residual paralysis at 60 days after the onset of paralysis. |
Laboratory performance |
All virologic studies of AFP cases must be performed in a laboratory accredited by the Global Poliomyelitis Laboratory Network. |
Twenty-First-Century Approaches: Electronic Network Systems for Global Disease Detection
Surveillance changed radically from the mid-1980s as a result of technological developments – the rapid and widespread growth in cheap desktop computing power and software replacing a few massive mainframes, and the growth of the communications and information-rich Internet. Recent developments in this area have been shaped by the International Health Regulations which were revised in 2005 to update capacity and standards of the reporting of disease events. The 2005 Regulations expanded the traditional concerns of the International Health Regulations and provided a new framework for the management of events that may constitute a public health emergency of international concern (Figure 2.22). Under the revised Regulations, Member States are required to notify the WHO of all events which may constitute a public health emergency of international concern (Article 6.1), whether naturally occurring, intentionally created or unintentionally caused. Four diseases are subject to notification under all circumstances: human influenza caused by a new subtype; poliomyelitis due to wild-type poliovirus; severe acute respiratory syndrome (SARS); and smallpox. The revised International Health Regulations set minimum requirements for developing and maintaining core capacity for the detection of, and response to, public health emergencies of international concern (‘core capacity requirements for surveillance response’). Internet-based systems of real-time disease surveillance lie at the heart of these developments.
The WHO Global Outbreak Alert and Response Network (GOARN)
The rise of newly emerging diseases, the pandemic spread of influenza and the threat of bioterrorism have highlighted the essential function of global disease surveillance in the maintenance and promotion of international health in the early twenty-first century (Castillo-Salgado, 2010). To this end, the Global Outbreak Alert and Response Network (GOARN) for the early detection of, and rapid response to, outbreaks of diseases of international importance was formalised by the WHO in April 2000 (Heymann, et al., 2001). Conceived as a “network of networks” (Lemon, et al., 2007, [link]), and formed as an international collaboration of some 140 public, private, non-governmental and intergovernmental institutions and organisations worldwide, GOARN is overseen by the WHO Global Alert and Response (GAR) programme as the principal WHO surveillance network for international outbreak alert and response (Figure 2.39).
Source: redrawn from World Health Organization (2005e).
GOARN operations
GOARN operates in three key areas: outbreak alert (detection, verification and communication); outbreak response (risk assessment, technical advice and support, field investigation, research and communication); and preparedness (assessment, planning, training, stockpiles, research and communication). For these purposes, GOARN connects both formal and informal sources of outbreak information. Formal sources include a range of governmental agencies, universities, laboratories and other institutions that form part of the global network of WHO collaborating centres, along with international agencies and WHO regional and country offices. Informal sources include non-governmental organisations (such as the United Nations Children’s Fund (UNICEF), the United Nations High Commissioner for Refugees (UNHCR), the International Committee of the Red Cross, the International Federation of Red Cross and Red Crescent Societies and international humanitarian non-governmental organisations such as Médecins sans Frontières), along with informal Internet-based disease surveillance and scanning systems such as the Global Public Health Intelligence Network (GPHIN) described in Section 2.8.
Real-time information gathered by GOARN is examined on a daily basis by the WHO Outbreak Verification Team. Daily reports on suspected and verified events are then distributed to specified WHO staff at Geneva and in the Regional Offices, while a weekly electronic Outbreak Verification List (including summary details of the disease, location, source of report, number of cases and deaths and investigation status) is distributed throughout the GOARN network. Once an outbreak has been verified, situation reports are posted on the WHO website and in Weekly Epidemiological Record. Outbreak responses are implemented by GOARN partners, while WHO HQ has investigative teams for rapid dispatch to outbreak sites (Heymann, et al., 2001).
Global Laboratory Networks and Electronic Surveillance Systems
The WHO maintains programmes for the monitoring and control of a number of well-established diseases and coordinates a number of electronic systems and databases that link networks of laboratories and other facilities worldwide. Examples of such systems include DengueNet (dengue), Global Foodborne Infections Network (foodborne infections) and, for the purposes of illustration here, GISRS and FluNET (influenza).
Global Influenza Surveillance and Response System (GISRS) and FluNET
The Global Influenza Surveillance and Response System (GISRS) (formerly known as the Global Influenza Surveillance Network) was originally established in 1952 as a network of laboratories to provide the WHO and its Member States with information on which to implement influenza control measures. As of 2011, the network was comprised of six WHO Collaborating Centres (Atlanta, USA; Beijing, China; London, UK; Melbourne, Australia; Memphis, USA; and Tokyo, Japan), four Essential Regulatory Laboratories (Woden, Australia; Potters Bar, UK; Rockville, USA; and Tokyo, Japan) and 136 institutions that are recognised by the WHO as National Influenza Centres (Figure 2.40). The GISRS monitors the evolution of influenza viruses and provides recommendations on issues that include laboratory diagnostics, vaccines, antiviral susceptibility and risk assessment. The GISRS also serves as a global alert mechanism for the emergence of influenza viruses with pandemic potential.
Source: GISRS, WHO (www.who.int).
Within the framework of GISRS, FluNET provides an electronic system that monitors emerging strains and subtypes of influenza virus and uses this information for the production of seasonal influenza vaccines. The data are provided remotely by National Influenza Centres and other national influenza reference laboratories collaborating actively with GISRS, or are uploaded from WHO regional databases. This system provided early alert of human cases of influenza A/H5N1 in Hong Kong in 1997.
2.8 Evolving Surveillance Practices
Informal Internet-Based Global Reporting Systems
Recent years have seen the development of a spectrum of ad hoc informal Internet-based international and global disease surveillance systems and platforms. These have opened up alternative channels for the rapid detection and reporting of communicable disease outbreaks. Such Internet resources also have the potential to reduce costs and to increase the transparency of reporting. We have already referred to one such ‘informal’ system, GPHIN, in our discussion of the WHO’s GOARN (Section 2.7). Here, we provide a brief review of GPHIN and two other prominent informal systems, ProMED-mail and HealthMap. An overview of the broad range of operative systems and platforms is provided by Castillo-Salgado (2010).
The Global Public Health Intelligence Network (GPHIN)
The Global Public Health Intelligence Network (GPHIN) was established in 1998 by the WHO in partnership with the Public Health Agency, Canada, as a web-based network for the scanning of Internet media (including news wires, online newspapers and public health email services such as ProMED-mail) with a view to detecting potential disease outbreaks globally. The information is filtered for relevancy by an automated process, and then analysed by GPHIN officials. Notifications about public health events that may have serious public health consequences are verified by the WHO and then forwarded to users (Mykhalovskiy and Weir, 2006).
ProMED-mail
ProMED-mail was established by the Federation of American Scientists’ Program for Monitoring Emerging Infectious Diseases (ProMED) in 1994 and has operated as a programme of the International Society for Infectious Diseases since 1999. ProMED-mail is an Internet-based system for the rapid global dissemination of information on outbreaks of communicable diseases and acute exposures to toxins that affect human health. It is a non-hierarchical system that promotes the electronic exchange of information on diseases among a variety of sources, including international organisations, ministries of health, laboratories, practitioners and the public. Submitted reports are screened, reviewed and moderated, before being posted to the network and distributed to subscribers by email. As already noted, ProMED-mail forms one of the sources on which GPHIN draws. Further details of ProMED-mail are available at http://www.promedmail.org.
HealthMap
HealthMap, founded in September 2006 and affiliated to the Children’s Hospital Informatics Program at the Harvard-Massachusetts Institute of Technology (MIT) Division of Health Sciences and Technology, utilises online informal sources for disease outbreak monitoring and mapping within a geographical information system (GIS) framework. As described by Freifeld, et al. (2008), HealthMap provides a global view of communicable disease outbreaks as reported by the WHO, ProMED-mail, Google News and Eurosurveillance. The automated system operates to monitor, organise and filter information with a view to providing real-time intelligence on emerging diseases via a website (www.healthmap.org) and a mobile app (‘Outbreaks Near Me’).
Regional Disease Threat Tracking Tools: The European Commission
An Early Warning and Response System (EWRS) was implemented by the European Commission in 1998 as a means of gathering and analysing data on emerging public health threats to the member states of the European Community. Since 2007, the system has been hosted in Stockholm, Sweden, by the European Centre for Disease Prevention and Control (ECDC). Notifications received from member states through the EWRS and through other epidemic surveillance activities (including the active screening of national epidemiological bulletins and informal sources such as ProMED-mail, GPHIN and the media) are documented and monitored through a dedicated database (Threat Tracking Tool, or TTT) that was first activated in June 2005. Between June 2005 and December 2009, a total of 806 threats were monitored through the TTT, representing an average of 13 threats per month (range 5–39) and with distinct seasonal peaks in the summer and autumn (Figure 2.41). Of these threats, 582 were initially identified through confidential sources (including 233 through EWRS) and 224 through public channels. Of the latter, ProMED-mail (85 threats) and GPHIN (32 threats) were the single most important sources of information (European Centre for Disease Prevention and Control, 2010).
Source: redrawn from European Centre for Disease Prevention and Control (2010, Figures 1, 2, [link]).
Sentinel Practices
The legal requirements to notify critical infectious diseases are tending to be left behind by the reality of disease proliferation. As a result, blanket reporting is increasingly replaced by sampling systems in which sentinel practices are used to pick up trends in disease prevalence. Some cities have pioneered local monitoring, of which the Seattle Virus Watch Program of the 1960s is an outstanding early example (Hall, et al., 1970). In the developing world, sentinel surveillance is the only cost-effective way of monitoring population health. As an example, Figure 2.42 maps the HIV sentinel surveillance rates for pregnant women in Botswana, 2002–5.
2.9 Conclusion
Timely and accurate surveillance data which are geographically and temporally coded lie behind any control strategy which attempts to interrupt the spatial propagation of communicable disease from one area to another. For, without such information, the development of appropriate control strategies to inhibit epidemic upturns rapidly descends into a Delphic art. Public health surveillance is the ongoing, systematic collection, analysis and interpretation of health data essential to (i) the planning, implementation and evaluation of public health practice and (ii) disease prevention and control. For control purposes, public health surveillance data systems should have the capacity to collect and analyse data, disseminate data to public health programmes (Langmuir, 1963; McNabb, et al., 2002), and regularly evaluate the effectiveness of the use of the disseminated data (Miller, et al., 2004; Regidor, et al., 2007). Public health information systems may include data collected for other purposes, but which are essential to public health and are often used for surveillance. But such data often lack critical elements of surveillance systems (Choi, et al., 2002). For example, vital statistics data are critical to surveillance, particularly for chronic conditions. But they do not focus on specific outcomes and are often collected for other purposes (for example, legal burial or cremation), and they may not be timely (Stroup, et al., 2003).
In this chapter, we have examined the development of surveillance systems across a variety of geographical scales from the local (bills of mortality), through the national (the US NEDSS framework) to the global (WHO epidemiological surveillance), as well as through time from the seventeenth to the twenty-first centuries. Our analysis of the ways in which surveillance data feed into control strategies begins in the next chapter with quarantine and isolation.
Appendix 2.1: Communicable Disease Categories
Table A2.1 gives the 123 sample communicable disease categories, along with their associated ICD-10 codes, analysed in International Patterns of Communicable Disease Surveillance, 1923–83 (Section 2.7).
Table A2.1 Sample communicable disease categories for analysis: Certain Infectious and Parasitic Diseases (ICD-10 A00–B99)
ICD-10 code |
Title of category |
Diseases1 |
|---|---|---|
A00–A09 |
Intestinal infectious diseases |
Cholera (A00); typhoid and paratyphoid fevers (A01); other salmonella infections (A02); shigellosis (A03); other bacterial intestinal infections (A04); botulism (A05); other bacterial foodborne intoxications (A05); amoebiasis (A06); other protozoal intestinal diseases (A07); viral and other specified intestinal infections (A08); diarrhoea and gastroenteritis (A09). |
A15–A19 |
Tuberculosis |
Respiratory tuberculosis (A15–A16); tuberculosis, non-respiratory (A17–A19). |
A20–A28 |
Certain zoonotic bacterial diseases |
Plague (A20); tularemia (A21); anthrax (A22); brucellosis (A23); glanders (A24); rat-bite fevers (A25); leptospirosis (A27); other zoonotic bacterial diseases, not elsewhere classified (A28). |
A30–A49 |
Other bacterial diseases |
Leprosy (A30); infection due to other mycobacteria (A31); tetanus (A33–A35); other tetanus (A35); diphtheria (A36); whooping cough (A37); scarlet fever (A38); meningococcal infection (A39); other septicaemia (A41); actinomycosis (A42); bartonellosis (A44); erysipelas (A46); gas gangrene (A48); rhinoscleroma (A48); colibacillosis (A49). |
A50–A64 |
Infections with a predominantly sexual mode of transmission |
Congenital syphilis (A50); syphilis (A50–A53); early syphilis (A51); late syphilis (A52); other and unspecified syphilis (A53); gonococcal infection (A54); chlamydial lymphogranuloma (venereum) (A55); chancroid (A57); granuloma inguinale (A58); trichomoniasis (A59); unspecified sexually transmitted disease (A64). |
A65–A69 |
Other spirochaetal diseases |
Yaws (A66); relapsing fever, tick-borne (A68); relapsing fever, unspecified (A68); other spirochaetal infections (A69). |
A70–A74 |
Other diseases caused by chlamydiae |
Psittacosis (A70); trachoma (A71). |
A75–A79 |
Rickettsioses |
Typhus fever (A75); Brill’s disease (A75); typhus, endemic (murine typhus) (A75); spotted fever (A77); Boutonneuse fever (A77); Q fever (A78); other rickettsioses (A79); trench fever (A79). |
A80–A89 |
Viral infections of the CNS |
Poliomyelitis (A80); atypical virus infections of central nervous system (A81); rabies (A82); mosquito-borne viral encephalitis (A83); tick-borne viral encephalitis (A84); encephalitis lethargica (A85); unspecified viral encephalitis (A86); viral meningitis (A87); other viral infections of central nervous system, not elsewhere classified (A88); unspecified viral infection of central nervous system (A89). |
A90–A99 |
Arthropod-borne viral fevers and viral haemorrhagic fevers |
Dengue fever (A90); other arthropod-borne viral fevers, not elsewhere classified (A93); sandfly fever (A93); unspecified arthropod-borne viral fever (A94); yellow fever (A95); arenaviral haemorrhagic fever (A96); other viral haemorrhagic fevers, not elsewhere classified (A98); unspecified viral haemorrhagic fever (A99). |
B00–B09 |
Viral infections characterised by skin and mucous membrane lesions |
Chickenpox (B01); zoster (B02); smallpox (B03); measles (B05); rubella (B06); foot-and-mouth disease (B08). |
B15–B19 |
Viral hepatitis |
Viral hepatitis (B15–B19); acute hepatitis B (B16); other acute viral hepatitis (B17); chronic viral hepatitis (B18). |
B25–B34 |
Other viral diseases |
Mumps (B26); infectious mononucleosis (B27); viral conjunctivitis (B30); other viral diseases, not elsewhere classified (B33). |
B35–B49 |
Mycoses |
Dermatophytosis (B35); candidiasis (B37); coccidioidomycosis (B38); histoplasmosis (B39); blastomycosis (B40); other mycoses, not elsewhere classified (B48); unspecified mycosis (B49). |
B50–B64 |
Protozoal diseases |
Malaria (B50–B54); unspecified malaria (B54); leishmaniasis (B55); African trypanosomiasis (B56); Chagas’ disease (B57); toxoplasmosis (B58); other predominantly sexually transmitted diseases, not elsewhere classified (B63); unspecified protozoal disease (B64). |
B65–B83 |
Helminthiases |
Schistosomiasis (B65); other fluke infections (B66); echinococcosis (B67); other cestode infections (B71); filariasis (B74); trichinellosis (B75); ancylostomiasis (B76); ascariasis (B77); other intestinal helminthiases, not elsewhere classified (B81); unspecified intestinal parasitism (B82); other helminthiases (B83). |
B85–B89 |
Pediculosis, acariasis and other infestations |
Pediculosis (B85); scabies (B86); unspecified parasitic disease (B89). |
B99 |
Other infectious diseases |
Other and unspecified infectious diseases (B99). |
Notes:
1 Three-character ICD-10 codes in parentheses.
