Tests have shown that the strain in Haiti’s cholera outbreak is similar to cholera strains found in South Asia, the CDC said on Monday, Agence France-Presse reports (11/1).

“The new findings from CDC’s laboratory are based on a method of ‘DNA fingerprinting’ called pulsed field gel electrophoresis (PFGE), which analyzes DNA patterns that can then be compared with PFGE patterns of cholera strains from other regions of the world,” according to a CDC press release. The test, which was performed on 13 samples from Haitian cholera patients, found that they “are the same strain and similar to a cholera strain found in South Asia,” the CDC states, noting that the findings are “not unexpected.” According to the press release, additional “information about this strain, including the possibility that it might be found in other regions of the world, is anticipated from additional studies” (11/1). But further testing might not explain how the outbreak in Haiti started, the CDC said, AFP notes.

“Although these results indicate that the strain is non-Haitian, cholera strains may move between different areas due to global travel and trade,” Haitian Minister of Health Alex Larsen said of the findings, AFP writes. “Therefore, we will never know the exact origin of the strain that is causing the epidemic in Haiti. This strain was transmitted by contaminated food or water or an infected person,” Larsen said (11/1).

“The finding intensifies scrutiny on a U.N. base above a tributary to the Artibonite River that is home to a contingent of recently arrived peacekeepers from Nepal, a South Asian country where cholera is endemic and which saw outbreaks this summer,” the Associated Press/Seattle Times reports.

The CDC’s Christopher Braden pointed out that South Asia is the region around the Indian subcontinent, which includes India, Pakistan and Nepal. The finding rules out some theories, “including a hypothesis that the strain might be related to a 1990s South American outbreak, Braden said. He said the strain was ‘fairly common.'”

“Following the CDC report, U.N. mission spokesman Vincenzo Pugliese said U.N. personnel took environmental samples around the [Nepalese] base Oct. 24, including from septic tanks, and tests by a private laboratory found no cholera. He added that the mission ‘welcomes the scientific contribution of the national public health laboratory in Haiti and the CDC to the understanding of the current cholera outbreak in Haiti,'” according to the news service. The article also describes recent visits to the Nepalese U.N. base, which the AP/Seattle Times said “reeked of human waste” in an area nearby (Katz, 11/1).

In related coverage, The Atlantic examines the outbreak in Haiti and looks at how the situation is being addresses on the ground. “As the crisis continues, the government and international institutions are distributing Clorox as widely as possible. And their efforts have diminished the number of new cases and deaths. But in Haiti, cholera is here to stay. Even if the epidemic can be contained in the near term, infected bodies buried without being sanitized will contaminate ground water,” the magazine writes.

Jean William Pape, director of the Haitian health organization GHESKIO, said he “hoped the epidemic would ‘create an incentive’ for the government to provide ‘what we have needed for a long time: adequate sanitary conditions for the population'” (Gaestel, 11/1).