The Origin of the Haitian Cholera Outbreak Strain

When I was traveling in Nepal this past November to assist in creating the Nepal Ambulance Service, cholera was beginning to appear in Haiti. It had long been predicted that infectious diarrhea of some sort would become epidemic in Haiti, given the horrible crowded living conditions of persons displaced by the earthquake of January 2010.

An article in the New England Journal of Medicine (364;1:33-42) authored by Chen-Shan Chin and colleagues shed light on the origin of the strain that has already infected nearly 4,000 persons and killed two to four percent of infected persons. Using sophisticated DNA techniques, it was determined that there is a close relationship between the Haitian isolates of Vibrio cholerae and strains of this germ identified in Bangladesh in 2002 and 2008. The Haitian strain was less closely related to Vibrio cholerae from South America.

The authors concluded that cholera currently ripping through Haiti originated from a “distant geographic source.” The source could easily have been visitors or a relief group that came to Haiti from Asia, although this is not proven. It’s always a risk in a post-disaster situation that rescuers will carry germs with them from the countries of origin. This has not been studied, and there is not yet a recommendation to attempt to disinfect the gastrointestinal tracts (e.g., with antibiotics) of relief workers before they are deployed.

Personal hygiene is important for self protection. There is no evidence to suggest that it prevents introduction of a nasty germ like Vibrio cholerae, but it can’t hurt. Certainly, everyone must do their best to avoid contaminating the water supply with human waste, and support reasonable hand washing techniques after contacting wastes and during food handling.

Once moderate or serious cholera occurs, there is good evidence (New England Journal of Medicine 364;1:5-7) to suggest that antibiotics (e.g., doxycycline, azithromycin, or ciprofloxacin for strains susceptible to these antibiotics) shorten the duration of illness and are important to reduce the “shedding” (via the diarrheal stools) of infectious organisms and thereby the spread of disease.