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Biological Incidents 

Biological Incidents
Biological Incidents

Ian Greaves

and Paul Hunt

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date: 28 November 2021

Recognition of a biological incident

A biological incident is likely to take one of the following forms:

  • Rapid epidemic spread of an infectious disease within or spreading from its normal geographic boundaries

  • Accidental escape of a pathogenic disease-causing organism from a laboratory

  • Deliberate release as part of terrorist or other malicious activity.

At the present time, the obvious examples of the first category include so-called avian or bird ‘flu’, swine flu, or the recent threat of imported Ebola (viral haemorrhagic) fever. An example of the second is the outbreak of smallpox in Birmingham in 1980. The UK has yet to be affected by a known deliberate release of a pathogenic organism but the USA was subject to anthrax attacks in 2001.

Natural disease outbreaks

In general, a natural disease outbreak presents different challenges to those of a conventional major incident. Its onset is likely to be gradual and identification will generally follow recognition of clusters of typical clinical features identified by conventional surveillance methods. In the majority of cases, effective management will not require the implementation of major incident protocols or conventional local scene management, but will be achieved by the extension of established clinical and other methods. However, additional measures such as stockpiling of vaccines, changes in border controls, and treatments for specific threats may be required, as will plans to ensure availability of assets such as intensive care beds and infectious disease facilities (including isolation capability) depending on the analysis of possible threats.

Accidental release of pathogenic organisms

There is a theoretical risk of accidental release of a pathogenic organism from one of the high-security laboratories in the UK licensed to handle them. However, biosecurity measures have ensured that no such incident has occurred in the last 30 years.

Bioterrorism incidents

It is fortunate that biological weapons are, for the most part, sufficiently difficult and hazardous to produce that they are used less frequently than other methods such as conventional explosives and chemicals.

The US Centres for Disease Control and Prevention (CDC) has defined the ‘Big Six’ main biological agents that threaten the most significant public health impact and have the greatest potential for large-scale dissemination and interpersonal transmission. These are considered ‘Category A’ agents and are listed in Box 9.1. Category B agents are moderately easy to disseminate and have lower morbidity and mortality rates. Examples of these are listed in Box 9.2.

Category C agents are pathogens that could potentially be engineered for mass dissemination because of their availability, ease of production, and potential for high morbidity and mortality. Examples of these are listed in Box 9.3

Features of an intentional biological agent release

A bioterrorism attack is most likely to be initiated in a covert manner in order to disguise the release of the pathogen and avoid the recognition of the release and a timely response by the emergency services. Therefore, recognition of such a release will be more challenging and occur over a longer period of time during which the pathogen may be widely disseminated.

Possible scenarios include:

  • spread of disease by an intentionally infected individual

  • contamination of air or water via ventilation or storage systems

  • contamination of foodstuffs or introduced via animal vector

  • Intentional modification (e.g. genetic) of an existing pathogen.

Crucially, an intentional disease carrier is likely to actively avoid treatment, unlike a genuine victim who will seek assistance at an early opportunity. It is theoretically possible that an innocent individual might be forcibly infected with a pathogenic organism although no example has yet been recorded.

Possible early clinical and environmental indicators of an intentional biological agent release incident are in Table 9.4. Recognition by even the most effective public health surveillance systems will still be delayed until a sufficient number of cases appear and data is collected and analysed. Table 9.5 shows some of the public health surveillance indicators that may be seen.

Table 9.4 Distinguishing between an acute and delayed presentation



Detection by

Emergency services, emergency departments, general public

Primary healthcare professionals, general public, HPA surveillance


Detection over minutes to hours

Detection over hours to days


Occurs in circumscribed area

May or may not occur in clusters


May have a shared exposure

May or may not occur from a shared exposure


Also consider chemical agents, biotoxins and radiological threat

Consider radiological material causes

Table 9.5 Samples to be taken in a biological incident (actual or suspected)




Blood cultures

Extended aerobic and anaerobic culture

Two sets of blood cultures immediately (from one bleed) with another two if possible within the first hour (also from one bleed). Document if antibiotics have been given prior to sampling


Serology and biological toxin assays

  • 2 × 10mL clotted blood, for both acute (admission) and convalescent phases

  • Acute sample may be used for toxin assays, freeze and save any excess

  • Whole blood

  • (EDTA)

Molecular investigations, e.g. PCR

2 × 10mL or 4 × 5mL whole blood acute phase


Microscopy, culture, and storage

Clean catch into sterile container—optimal volume >20mL

Natural epidemic disease activity

The majority of natural disease outbreaks will occur against a background of a low but ongoing incidence of cases and may be affected by the uptake of population-based preventative measures such as vaccination. In general, these outbreaks are associated with morbidity rather than mortality, although deaths (e.g. from measles) can occur. Infectious disease outbreaks of this kind are controlled or managed using conventional public health processes. Conventional major incident structures are unlikely to be needed, at least at the local level, although national coordination may be required. The response of the public and media to a naturally occurring outbreak will be dramatically different to that to a suspected terrorist incident. Occasionally unusual imported infectious diseases do occur, but awareness of potential risk factors, such as travel to an area known to harbour the disease, together with clinical suspicion in the event of an unusual presentation will generally be effective in achieving control of any actual or potential outbreak. The remainder of this chapter will concentrate on deliberate release of infective agents, although in some areas (e.g. the hospital response), there will be considerable overlap.

Recognition of an intentional biological agent release

Non-contagious agents

Non-contagious agents, such as anthrax bacillus spores, will require an effective means of widespread dispersal in order to clinically affect large numbers of individuals, as the pathogen is not easily transmitted from person to person. Potential techniques may include the use of explosive canisters containing agent or spraying devices attached to vehicles or aircraft. Smaller numbers may be affected by material sent by post as in the US anthrax attacks of 2001. The outcome of dispersal of these agents is more predictable in that only those in the vicinity of the release will be affected. Prompt management should contain further spread of infection.

Contagious agents

Some agents, such as smallpox and plague, spread from person to person so rapidly that widespread dispersal may not be necessary. A small amount of agent dispersed and infecting only a few individuals will have the potential to start an epidemic affecting millions. Such a method is inherently unpredictable in its outcome, and could result in huge numbers of casualties spread over large areas crossing national boundaries.


Non-contagious biological agents are usually dispersed either by air in the form of fine particles (aerosols) or by contamination of food or water sources. Contagious agents can also be transferred by person-to-person spread from a deliberately infected individual. Once a deliberate release has occurred, the key factors in how the disease will spread are the ease and rapidity of its person-to-person transmission.

Bioterrorism surveillance

The sooner a deliberate biological release is identified, the more morbidity and mortality can be reduced by rapid containment and effective treatment. Disease activity monitoring in populations is a responsibility of public health services supported by central government agencies. Normally focused on routine infectious diseases of public health concern, such as tuberculosis or measles, or natural disease outbreaks, such as Ebola, the same systems are used to detect outbreaks which may be the result of bioterrorist activity. In the UK, the surveillance and response framework is coordinated by the Civil Contingencies Secretariat, Department of Health (DH), and Public Health England (PHE). General approaches to surveillance are listed in Box 9.6 and the features of an effective surveillance system are listed in Box 9.7.

Effective, robust communication networks and information technology systems are vital so that public health information can be shared rapidly and effectively. With the vulnerability of technology systems to a coordinated terrorist attack and limitations in infrastructure, resources may be insufficient to cope with the inevitable higher demands and activity during the response to a bioterrorist incident.


The UK detection system consists of local infectious disease epidemiology services staffed by consultants in communicable disease control (CCDC) working closely with local health services. Regional laboratories maintained by PHE provide diagnostic services and can also offer expert advice on the clinical and organizational management of outbreaks. PHE also maintains reference laboratories with expertise on specific pathogens.

Deliberate release

Deliberate biological releases may be declared or covert. The responses to a declared release will obviously be more rapid and will be coordinated centrally. Extra resources will be supplied as required to areas affected. Detection of a covert release will only be possible once the first cases of infection begin to arise and the pattern is recognized. The appearance of diseases that rarely occur in nature may alert the surveillance organizations to the possibility of a covert deliberate release. For example, current guidelines state that deliberate release should be considered as a cause in the event of even a single case of inhalational anthrax.

Contact tracing

Once the causative agent has been identified, every individual who has been, or may have been, exposed needs to be traced, decontaminated if necessary, and offered appropriate treatment. This response is coordinated via an outbreak control team consisting of a CCDC and other appropriate subject matter experts.

Biological agent biodromes

Particular groups of symptoms, or biodromes, can be associated with certain organisms. Therefore, the appearance of significant numbers of new cases presenting with a common biodrome or one or more cases of an unexpected or rare biodrome could indicate the release of a biological agent. Table 9.1 lists examples of such biodromes and their associated pathogens.

Table 9.1 Biological agent biodromes. Reproduced with permission from Greaves and Hunt, Responding to Terrorism: A Medical Handbook. Elsevier 2011

Principal symptoms

Potential pathogen

Fever + respiratory compromise

  • Pulmonary anthrax

  • Plague

  • Ricin

  • Tuberculosis

  • SARS

  • Tularaemia

  • Glanders

  • Q fever

  • Staphylococcus enterotoxin B

  • Pneumonia, e.g. Chlamydia, Legionella, Mycoplasma

Fever + generalized rash

  • Smallpox

  • Viral haemorrhagic fevers (VHF)

  • Measles

  • Scarlet fever

  • Dengue fever

  • Chickenpox

  • Typhoid

Fever + skin blistering/localized skin signs

  • Cutaneous anthrax

  • Tularaemia

  • Glanders

  • T-2 mycotoxin

Neurological features

  • Botulism

  • Equine encephalitis

  • CNS infections

Fever + shock/DIC

  • Viral haemorrhagic fever (VHF)

  • Meningococcal septicaemia

  • Malaria/dengue

  • Anthrax

  • Plague

  • Tularaemia

  • Smallpox

  • Ricin

Initial management of a suspected biological agent release incident

In general terms, the initial management of a biological outbreak involves:

  • clinical care of affected patients

  • identification of the causative agent, source, and transmission route

  • identification of at-risk groups and individuals

  • decontamination and control measures as appropriate

  • use of vaccines and/or antibiotics for public health protection

  • provision of information to the public and the media.

Local clinical care of affected patients will be the responsibility of NHS acute hospitals and community clinical services. Coordination of more serious outbreaks will also involve regional directors of public health, regional PHE epidemiologists, and the DH.

General incident management principles

The vital difference between a biological incident and any other type of incident is the delay between time of exposure to the causative agent and the onset of symptoms and hence recognition. Unless the release of the agent is immediately obvious, or an announcement is made by those responsible, index cases may travel a significant distance from the point of exposure before being identified, thereby creating considerable difficulty with containment of the incident and later contact tracing. This could allow the rapid spread of infection throughout the population, especially where the organism is highly virulent. The conventional boundaries and cordons of a more conventional incident will not apply in these cases.

On the rare occasions that a release is overt, conventional command and control of the incident may be possible. In order to achieve this, rapid containment is essential to prevent spread of infection and to ensure the provision of initial treatment as well as facilitating post-exposure prophylaxis if available for the organism concerned.

The assessment and treatment of biological incident casualties will depend on the suspected agent, information which may well be unavailable immediately following the incident. Provisional identification of the agent will often rely upon recognition of characteristic clinical signs until specialist laboratory testing can confirm the organism’s identity by serology or culture.

Universal (standard) precautions

Since the management of affected patients may involve the handling of body fluids, changing of dressings, and disposal of contaminated objects, it is absolutely essential that appropriate precautions are taken to prevent inadvertent transmission by exposure to potentially infectious body fluids, and to avoid injury by potentially contaminated sharp instruments.

Because it will not normally be possible to tell whether a casualty is carrying a disease, particularly in the early stages of an incident, a minimum level of precautions must be followed at all times. These are referred to as universal or standard precautions, as shown in Box 9.8.

Personal protective equipment

There are three categories of PPE for use in biological incidents:

  • Barrier PPE: gloves and gowns

  • Droplet PPE: gloves, gowns, and eye protection (i.e. face shields)

  • Aerosol PPE: gloves, gowns, and face masks/respirators.

The main route of infection spread between individuals is normally by direct contact. In addition to universal or standard precautions, additional contact precautions should be maintained to minimize transmission. Where facilities are available one means of achieving this is isolation. Gloves and a gown must be worn at all times. Face shields and eye protection should also be worn when conducting an examination or procedure that may involve aerosols or droplet formation, such as airway suctioning or the use of nebulizers. PPE should be removed between patients, and disposed of appropriately in marked clinical waste bins.

Airborne infection control and basic respiratory precautions

Small particles containing infectious pathogens may be formed by droplets expelled from the respiratory tract of an infected individual, or by intentional release in aerosol form. Close contact (generally accepted to be less than 1–2m) may not be required for transmission, although it may make person-to-person spread more likely. Prevention of airborne transmission requires a higher level of respiratory protection than can be offered by surgical masks (see Boxes 9.9 and 9.10).

Droplet spread involves larger, heavier particles (greater than 5 micrometres) requiring closer contact for transmission and may be protected against by wearing a surgical mask which reduces exposure and absorption via the mucosa of the upper respiratory tract and eyes.

Decontamination at scene

On rare occasions, a release may be identified while its effects are confined to a specific location. In such circumstances, immediate wet decontamination should be carried out, following local protocol. Further information regarding at-scene decontamination is shown on pp. [link][link]. Mass decontamination may be required for large-scale incidents, and the decision to carry this out must take into account:

  • the extent of the release

  • the environment at the release site

  • the risk of transmission

  • the persistency of the suspected agent.

Forward medical teams with full PPE and specialized equipment may be required to deal with casualties within the hot zone, especially where conventional trauma has occurred or casualties are entrapped. This degree of protective equipment will inevitably reduce the level of medical interventions that can be performed. However, at-scene decontamination may not be carried out if the recognition of an event is delayed. Once careful contact tracing leads to the identification of the potential source or location of the initial release, quarantine and decontamination of the area may be appropriate. A number of biological agents are highly persistent, especially if the environmental conditions are favourable, and therefore an effective cordon will be required to deny access and prevent further spread. It should be remembered that patients attending hospital from such a scene will require decontamination before admission.

Isolation and quarantine

Current regulations define the isolation precautions required for health workers against the most contagious and virulent organisms, such as those responsible for VHF (including Ebola). In the case of infection with the higher airborne risk group of VHF (including Lassa, Marburg, and Ebola viruses), additional airborne precautions are recommended. Isolation and PPE recommendations for these agents are given in Figure 9.1.

Fig. 9.1 Management algorithm for suspected viral haemorrhagic fever (VHF) presentation.

Fig. 9.1 Management algorithm for suspected viral haemorrhagic fever (VHF) presentation.

Reproduced under Crown Copyright from Advisory Committee on Dangerous Pathogens, Management of Hazard Group 4 viral haemorrhagic fevers and similar human infectious diseases of high consequence (November 2015) (

Surge planning

Hospital major incident plans for biological incidents must ensure that there is adequate surge capacity in the event of multiple cases of infection by the most highly contagious or potential harmful organisms. These plans should include the identification of a specific zone or ward as an isolation area. In the largest incidents, a regional, or even national, response may be necessary to provide adequate numbers of high-dependency beds.

Public health information

Early dissemination of accurate information is the key factor in reducing public panic. As well as monitoring infectious diseases, PHE is required to provide support and advice on how infectious disease threats can be managed. Fact sheets are available for several likely public health biological threats including anthrax, plague, botulism, and smallpox. Regular meetings and conferences also take place to enable discussion of the latest developments in infectious disease threats, diagnostic tests, and new treatment.

Biological agent transmissibility and public health impact

In order for a disease to be passed from individual to individual (transmitted), three main requirements have to be met—there have to be:

  • an infectious individual (the source)

  • a susceptible individual

  • a means of contact between them.

Methods of transmission of an organism or biotoxin include droplet spread, direct physical contact, or airborne spread. Thus the exposure required for transmission will depend on the mode of transmission of the organism or toxin. In terms of public health risk, agents which are reliably transmitted by airborne spread are the most dangerous, and most difficult to protect against.

Virulence refers to an organism’s ability to cause disease and relies on the initial number of infecting organisms or unit of biotoxin, the method or route of exposure, the defence mechanisms of the host, and the characteristics of the individual organism or biotoxin

A summarized comparison between biological agents in terms of their overall risk to public health is shown in Table 9.2.

Table 9.2 Comparison of biological agent by risk to public health. Reproduced with permission from Greaves and Hunt, Responding to Terrorism: A Medical Handbook. Elsevier 2011

Biological agent

Risk of P-P* transmission

Morbidity scale

Mortality scale









Food-borne pathogens




















Q fever








Water-borne pathogens




































Botulinum toxin




Epsilon toxin




Staphylococcus enterotoxin B




T-2 Mycotoxin




* Person-to-person.

Mathematical models of infection spread

The behaviour of infectious diseases can be modelled as a way of predicting disease outbreaks and refining responses. These models rely on certain assumptions, namely that the population can be subdivided into a set of distinct classes: Susceptible, Infectious, or Recovered. This is referred to as the SIR model. In order to understand the model, certain basic assumptions have to be accepted:

  • All individuals are in the ‘susceptible’ class at birth

  • Susceptible individuals are able to catch the disease (and become ‘infectious’)

  • Infectious individuals spread the disease to ‘susceptible’ individuals

  • Infectious individuals remain in the ‘infectious’ class for a given period of time (depending on the organism responsible)

  • Infectious individuals may then recover, entering the ‘recovered’ class

  • Individuals in the ‘recovered’ class may then be assumed to be immune for life (or at least against that particular strain of organism such as from an influenza epidemic).

Estimation of the effective contact rate in a given population is a key requirement for mathematical modelling of disease spread. This is the product of the total contact rate per unit time (effective or not) and the risk of transmission. However, there are limitations to this calculation as contact rates can vary widely between individuals and groups.

Transmission risks can only be determined from retrospective studies of previous outbreaks. These studies can also be useful in investigating the efficacy of a vaccination by comparison between vaccinated and unvaccinated groups for a specified organism.

Several software models are available to facilitate this process, as well as much more complex epidemic simulations, such as ‘Epigrass’. However, the modelling of irregular events, such as deliberate release, is very difficult and often unreliable because of the assumptions involved and the extrapolation from historical data.

Reproductive ratio

The basic reproductive ratio, R0, is defined as the average number of secondary cases occurring in a susceptible population. When R0 is greater than 1, the disease is capable of infecting susceptible individuals and the number of cases will therefore increase. Conversely, when R0 is less than 1, the disease will always fail to spread. Estimation of the R0 can help to quantify the risk of a given disease to the population. Comparative examples of R0 values are shown in Table 9.3.

Table 9.3 Examples of R0 values










> 100

Mass population models

Computer models are available to help predict disease spread in order to facilitate national, or even international, efforts to manage infectious outbreaks. The same models can also be used to generate scenarios for ‘tabletop’ exercises.

The Large-Scale Agent Model (LSAM) was developed by the National Centre for the Study of Preparedness and Catastrophic Event Response at the Johns Hopkins University, Baltimore, Maryland, USA. The LSAM can be used to plan for natural epidemics, and deliberate biological and chemical agent releases. This system involves complex computer simulation of communities representing real populations. One of the main focuses is on surge capacity, enabling scenarios to challenge available medical facilities in the event of a significant incident.

Pre- and post-exposure prophylaxis

Pre-exposure prophylaxis

Pre-exposure prophylaxis is the treatment provided in advance of potential exposure to a specific, or suspected, organism. It may take the form of a vaccination schedule or medical therapy, such as an antibiotic. The aim is to target individuals who are identified as being at increased risk of exposure. This may include routine immunization of a national population at risk of endemic diseases such as yellow fever, widespread immunization in response to a perceived new threat (e.g. avian ‘flu), or immunization of a more specific population (e.g. military personnel or health services staff).

Post-exposure prophylaxis

Post-exposure prophylaxis is the practice of providing treatment immediately after a suspected or confirmed biological agent release, in order to attempt to limit the duration, severity, incidence, and transmission of disease in asymptomatic individuals. The groups most likely to require post-exposure prophylaxis include:

  • individuals exposed at the incident scene (including emergency responders)

  • contacts of highly transmissible disease cases

  • hospital medical staff and laboratory workers.

Guidance regarding suitable post-exposure antibiotic prescribing is available from PHE. National stockpiles are available for mass treatment and guidance for obtaining these, as well as PGD’s for biological countermeasures, is outlined on pp. 238–9 and p240 respectively.

Use of vaccines

Vaccines may be used for both pre- and post-exposure prophylaxis. The smallpox vaccine can be used to limit disease severity post exposure. The anthrax vaccine is at the moment only provided to those at risk of exposure (veterinary staff, laboratory workers, and military personnel) and to reduce the risk of disease after exposure to anthrax in some cases.

The hospital response to a biological incident

Key elements of the hospital response to a confirmed, or suspected, biological release incident are listed in Box 9.11 and should be incorporated into hospital major incident plans.


It is rare for a biological incident to be recognized by emergency services working at the scene, or for warnings to have been given of a deliberate release. Were such to be the case, the hospital incident plan could be activated allowing for preparation of facilities for decontamination and treatment before casualties start to arrive. However, due to the inevitable delay in developing symptoms, casualties will usually attend hospital services sometime after the initial release took place. This is referred to as a ‘slow rise’ event. In these circumstances, hospital emergency departments and inpatient medical teams may be the first to recognize the features of a biological incident. Equally likely is that recognition will result from wider surveillance processes.

Provision of PPE and decontamination facilities

Appropriate PPE/PRPS must be worn by all personnel dealing with casualties. Decontamination measures may be required if casualties have been overtly and recently exposed to particulate infective material such as anthrax spores. In general, there is no requirement for decontamination of casualties presenting sometime after an event for screening or of those with established clinical disease although, in both cases, precautions must be taken to avoid infection of healthcare workers. Decontamination should be carried out in specifically designated areas.

If the individual reports possible exposure at the site of a suspected, or confirmed, release, a risk assessment should be made as to whether there is any remaining contamination of body or clothing. Appropriate action may also be required to deal with contaminated clothing or other materials left at the individual’s home or workplace.

Primary care

Primary and community care services may be involved in the response to an actual or potential biological incident in one or more of the following ways:

  • Management of the ill in the community and referral to secondary care as required

  • Management of exposed but unaffected individuals

  • Provision of advice and information to local community

  • Provision of prophylaxis under guidance from PHE

  • Reassurance and advice for the ‘worried well’.

Primary care health professionals should seek expert advice from PHE as early as possible if the potential features of an unusual outbreak are recognized. To ensure public safety and the safety of staff, invasive procedures and detailed patient assessment should be avoided. These can be more safely and appropriately performed after the patient arrives in hospital. PHE may advise on which hospitals are to be used in the case of specific biological incidents but advice should be sought from the hospitals before patients are transferred in case any special arrangements are required. In addition, it is vital that the ambulance service is warned, via their control, of any potential health and contamination risks. It is absolutely essential that comprehensive records of management decisions are kept in addition to contemporaneous clinical records. Details of actions taken, advice given, and those to whom information has been passed should be recorded. (See Table 9.4 and Box 9.12.)

Cardinal signs and tips for key biological agents

The advice in Figure 9.2 and Figure 9.3 is designed to assist hospital clinicians in the initial management of suspected biological agent releases.

Fig. 9.2 Advice for dealing with an actual or potential biological incident.

Fig. 9.2 Advice for dealing with an actual or potential biological incident.

Reproduced under Open Government License from Health Protection Agency, Cardinal signs and tips for key biological agents, 15/02/2011 (

Fig. 9.3 Responding to suspect packages and materials—actions to be taken.

Fig. 9.3 Responding to suspect packages and materials—actions to be taken.

Reproduced under Open Government License from Health Protection Agency, November 2006 (

The role of hospital clinicians

Patient welfare is the first priority, but appropriate infection control measures must be instituted immediately in order to minimize exposure to staff. Clinicians must seek advice at the earliest opportunity from the usual hospital sources such as infectious disease specialists and microbiologists. Infection control teams must be informed as well as PHE locally. Further clinical responsibilities are summarized as follows:

  • Assessment of risk of disease transmission to staff and other patients

  • Protection of staff who may be exposed to the patient

  • Assessment of the need for decontamination

  • Initial triage and life-saving treatment

  • Diagnose and formulation of a management plan

  • Clinical investigations

  • Effective communications.

A record must be kept of all staff (and anyone else), who has been in contact with infected patients (including personal contact details). It is also of vital importance to keep comprehensive records, not only of clinical decisions but also of management activity. Each entry must be dated, timed, and signed. A list of important information to document in case(s) of unusual illness is shown in Box 9.13.

Information cascade

Individual hospital major incident protocols should be followed, ensuring that information is appropriately, rapidly, and effectively shared between clinical and managerial staff. At all times, senior clinical staff must maintain a high degree of awareness of the arrival of unexplained or unexpected numbers of individuals presenting with similar symptoms or signs, information which should immediately be passed into the management chain. Senior staff should also ensure that local emergency services and PHE have been informed. A nominated individual should be tasked with seeking expert advice regarding the suspected organism involved, correct identification, and microbiological testing as well as clinical management requirements.

The senior clinician on duty for the emergency department is responsible for ensuring that all necessary PPE and decontamination resources are made available. Other hospital departments which will need to be informed so that they can prepare to receive patients include the general wards, intensive care, or high dependency units. Infection control teams will need to be informed to ensure adequate numbers of isolation bed spaces are made available. Off-duty personnel may need to be called in and the responsibility for this will need to be given to a prior nominated individual (see Figure 9.4).

Fig. 9.4 Information cascade for suspected biological incidents.

Fig. 9.4 Information cascade for suspected biological incidents.

* If a deliberate release is suspected, ensure the police have been informed if not already aware.

Maintaining the chain of evidence

In cases of possible intentional biological release, it is vital that patients’ personnel effects, as well as medical samples, are kept appropriately packaged and documented to ensure that the chain of evidence is maintained. This is especially relevant where samples may pass between several different departments or laboratories. Every movement of a sample should be documented. Appropriate attention must at all times be paid to biosecurity and infection risk.

Microbiological testing

Where the cause of an unusual or unexpected illness is unknown or uncertain, guidance recommends that screening samples are taken including toxicological and microbiological investigations, as well as routine haematology and biochemistry. Instructions for microbiological blind testing are shown in Table 9.5. Samples must be taken as early as possible, and wherever possible before specific drug therapy has been administered as long as life-saving treatment is not delayed. Standard precautions should be used in all cases with additional PPE (e.g. double gloves, eye and face protection, and FFP3 mask) if relevant or where highly infectious causes are suspected. Specimens should be handled, labelled, and transported as high risk.

The unidentified biological agent and ‘white powder’ incidents

The unidentified biological agent

Several technologies with the potential to offer rapid, portable, and automated analysis and diagnosis of known biological agents are currently being developed. These may one day allow the performance of ‘on-the-spot’ identification of suspicious materials at the site of release. This would offer significant advantages not only in identifying ‘harmless’ materials in the event of negative testing, but also to enable rapid control of spread with effective infection control measures and early post-exposure prophylaxis. Otherwise, common sense precautions must be followed. The substance must not be touched or moved, air conditioning switched off, the area isolated and closed, and staff who have been exposed to it identified. Expert advice can then be sought regarding the nature of the substance. (See also ‘Dealing with a suspect package (‘white powder incident’)’, pp. [link][link] and flowchart on p. [link].)