Cholera: assessing the risk to travellers and identifying methods of protection

This review is based on the findings of a consultation meeting involving consultants in travel medicine and focusing on the risks of cholera to the traveller. Cholera is a severe diarrhoeal disease transmitted via the faeco-oral route and commonly associated with poor sanitation. Between the years of 1995 and 2001, the WHO reported 1829 cases of cholera in developed countries, the majority of which were imported. However, it is believed that this figure reflects less than 10% of the true incidence of cholera due to milder cases being unrecognised, as well as significant underreporting. Travellers to epidemic countries may be at increased risk of contracting cholera if they ingest contaminated food or water. It has been estimated that there are 0.2 cases of cholera per 100,000 European and North American travellers, though there is some evidence that this rate is higher. Oral vaccines are a necessary and welcome advance as, in addition to preventing illness, they can minimise the possibility of transmission of cholera to disease-free regions. The morbidity from cholera can range from asymptomatic or oligosymptomatic infection to disruption of holiday and business plans, or even severe toxicity and dehydration. If untreated, severe illnesses can be fatal, although fatalities have not been reported among travellers for many years.