Study traces Haitian cholera to South Asian origin
The analysis fits with, but does not prove, the controversial idea that the disease came from U.N. troops dispatched from that region.
DNA analysis found that cholera bacteria recovered in Haiti were nearly identical to strains predominant in South Asia, and different from those found in Latin America, researchers said.
The most likely explanation is that the germs were released in excretions from people, but they could also have come from contaminated food or water brought in by people arriving from South Asia, he said.
Waldor is an author of a report published online Thursday by the New England Journal of Medicine. The paper confirms a South Asian link reported last month by the U.S. Centers for Disease Control, and presents a more detailed analysis of the DNA.
Cholera has sickened nearly 100,000 people in Haiti since October, and it’s feared the germ could infect six times that number. Before the current outbreak, no cholera had been confirmed in Haiti since World Health Organization record keeping began in the mid-20th Century. And no cases had been suspected for at least a century.
The origin of the outbreak became politicized with suspicions that U.N. soldiers from Nepal brought the disease to Haiti and transmitted it because of sanitation problems at their base. The suspicions were strengthened when sanitation problems and questionable human waste-dumping practices were found by journalists.
On Tuesday, The Associated Press obtained a copy of an undisclosed report by French epidemiologist Renaud Piarroux that said “no other hypothesis could be found” to explain how a strain never before seen in Haiti erupted in a village far from the coast and the earthquake zone, in an area directly abutting the peacekeepers’ base.
Waldor said his report is consistent with the Nepalese-troops hypothesis, but does not prove it or deal directly with it. The researchers didn’t compare the Haitian samples with those from Nepal or test Nepalese troops stationed in Haiti, he noted.
The researchers may examine cholera strains from Nepal and elsewhere around the world to get a better idea of where the Haitian cholera came from, he said.
“This fact simply will prove that the travel of infected individuals to areas that are at risk for epidemic cholera needs to be addressed as a public health concern,” he said.