Above: cholera treatment in Haiti (UN Photo/Marco Dormino)

By Alexander Britell

Haiti’s deadly cholera epidemic may have come from more than one strain, according to a report published in the Proceedings of the National Academy of Sciences of the United States of America.

According to the study, “Genomic diversity of 2010 Haitian cholera outbreak strains,” which was released Monday, the results showed “two distinct populations” of cholera coexisted in Haiti early in the epidemic, which has killed more than 7,000 Haitians.

“I think the message we’re conveying is that this is a bit more complicated than I think the initial reports would indicate,” University of Maryland Professor Rita Colwell, who led the study, told Caribbean Journal.

The team collected clinical samples from 81 Haitian patients who suffered symptoms of cholera collected from 18 towns across eight arrondissements of Haiti, covering three weeks in November 2010.

The disparate strains were in two populations, according to the study: one resembling strains from South Asia and Africa, and another resembling strains circulating in the Western Hemisphere.

And it’s possible, she said — though unproven — that one of the strains could have been indigenous to Haiti.

“There’s no evidence the the strain of this epidemic was not in Haiti [already], because there are no records,” she said. “They have had diarrhea cases in the past, according to hospitalizations, but we don’t have clinical data showing whether cholera was there or not. So it’s hard to say.”

It has been largely presumed that Haiti’s cholera came from a strain brought to the country shortly after the earthquake by United Nations peacekeepers from Nepal.

In August 2011, an article in the online medical journal mBio found that Haiti’s cholera originated in Nepal.

The Nepal cholera claim has led to backlash against the UN, along with a high-profile lawsuit seeking damages for victims.

The new results pointed to the conclusion that two different cholera strains existed in Haiti at the time of the outbreak, however.

“I think it calls [the Nepal explanation] into question,” she said. “I think it does — I think it really points out that this is a complicated situation, and there are other strains of cholera that are similar. The Nepal seems to be closest, but we don’t have any [clinical] data and we’re trying to put this together.”

A team of 21 scientists contributed to the study.