Gastrointestinal illness is the most common infection amongst visitors to the tropics, with Salmonella spp., Campylobacter spp. and Cryptosporidium spp. infections prevalent worldwide. Typhoid, paratyphoid, Shigella spp. and Entamoeba histolytica (amoebiasis) are usually encountered in visitors to the Indian subcontinent or sub-Saharan and southern Africa.
The approach to patients with acute diarrhoea is described. The benefits of treating travellers’ diarrhoea with antimicrobials are marginal. The differential diagnosis of diarrhoea persisting for more than 14 days is wide. Parasitic and bacterial causes, tropical malabsorption, inflammatory bowel disease and neoplasia should all be considered. The work-up should include tests for parasitic causes of chronic diarrhoea e.g. examination of stool and duodenal aspirates for ova and parasites, and serological investigation.
Tropical sprue is a malabsorption syndrome with no defined aetiology. It was typically associated with a long period of residence in the tropics or with overland travel but is now rarely seen. Giardia lamblia infection may progress to a malabsorption syndrome that mimics tropical sprue. If no cause is found, empirical treatment for Giardia lamblia infection with metronidazole is often helpful.
HIV-1 has now emerged as a major cause of chronic diarrhoea. This may be due to HIV enteropathy or infection with agents such as Cryptosporidium spp., Isospora belli or microsporidia. However, many other causes of chronic AIDS-associated diarrhoea seen in the developed world are less common in tropical setting e.g. CMV or disseminated Mycobacterium avium complex infections.
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