As suspected, Nepalese soldiers traveling to Haiti to aide in the recovery efforts after the January 2010 earthquake are the source of the deadly cholera outbreak that killed more than 6,000 people and left some 300,000 seriously ill, according to a study published today (August 23) in mBio.
Paul Keim, a biology professor at Northern Arizona University and director of the Pathogen Genomics Division of the non-profit Translational Genomics Research Institute (TGen), and his colleagues used whole genome sequencing to compare 24 Nepalese samples of Vibrio cholerae, the causative agent of cholera, with 10 samples of the bacteria from Haiti. All the samples showed high sequence similarity, with some that “were almost identical,” the researchers report. The results confirm earlier suspicions that peacekeepers from Nepal brought the disease with them to Haiti when responding to the earthquake, which were based on the timing of the Haitian outbreak—just after a cholera outbreak in Midwestern Nepal. Though the Nepalese outbreak was controlled by mid-August, just before the soldiers departed for Haiti, they could still have carried the disease with them.
"The great similarity of Haitian cholera with Nepalese cholera is based upon the highest resolution DNA methods available, and point to a probable source of this devastating disease outbreak," said Keim, who has used similar genetic tracking methods to help identify the source of the 2001 anthrax letters, in a press release.
Keim and his colleagues hope that the findings could help avoid similar outbreaks in the future, when international aid is brought in to disaster areas. "This effort validates the power of advanced molecular tools in investigating outbreaks of this nature,” Lance Price, an associate professor at TGen and co-author of the new study, said in a press release. “The goal now should be finding ways to prevent such outbreaks, perhaps through screening prior to deployment.”