Show Summary Details
Page of

Adenovirus 

Adenovirus
Chapter:
Adenovirus
DOI:
10.1093/med/9780198729228.003.0042
Page of

PRINTED FROM OXFORD MEDICINE ONLINE (www.oxfordmedicine.com). © Oxford University Press, 2016. All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in Oxford Medicine Online for personal use (for details see Privacy Policy and Legal Notice).

date: 18 November 2019

Amoebiasis, caused by Entamoeba histolytica, only occurs in humans and primates. E. histolytica is indistinguishable from the non-pathogenic dispar and moshkovskii. E. histolytica occurs worldwide, but the majority of cases occur in developing countries—approximately 500 million infected. The true incidence of asymptomatic carriage is unclear. Paediatric amoebiasis accounts for less than 10% of all cases, probably higher in resource-poor countries. E. histolytica is spread by the faecal–oral route. Cysts persist in soil for months and are resistant to chlorination and gastric acid. Ingested cysts develop into trophozoites in the small intestine, then pass to the colon. Trophozoites cannot survive outside the body. Ninety per cent of carriers remain asymptomatic and eliminate the organism without treatment. Four to 10% develop colitis, with diarrhoea progressing to dysentery. Fulminant colitis with perforation is rare. Amoebic liver abscess is the commonest systemic manifestation (0.5–1.5%). Very rarely, disease disseminates further by rupture of the amoebic liver abscess or intestinal perforation. A good travel history, often going back years, is vital. Stool microscopy is the mainstay of diagnosis; however, differentiation between Entamoeba species is difficult. If dysentery is present, then fresh warm stool needs to be sent urgently for microscopy to look for trophozoites with ingested red blood cells.Antigen detection has high sensitivity and specificity in dysentery and amoebic liver abscess. Ninety per cent of symptomatic patients develop E. histolytica antibodies. Treatment for invasive bowel or systemic disease includes metronidazole or tinidazole; a recent Cochrane review concluded that tinidazole is superior. Metronidazole is not an effective therapy to remove luminal carriage.

Access to the complete content on Oxford Medicine Online requires a subscription or purchase. Public users are able to search the site and view the abstracts for each book and chapter without a subscription.

Please subscribe or login to access full text content.

If you have purchased a print title that contains an access token, please see the token for information about how to register your code.

For questions on access or troubleshooting, please check our FAQs, and if you can't find the answer there, please contact us.