Cholera in Haiti in the "remote" source (src)

A woman wears a child showing symptoms of cholera at the entrance to one hospital in the neighbourhood of the city of Soléil de Port - au Prince in November. (Ramon Espinosa/Associated Press)

The strain of cholera behind the emergence of Haiti closely match samples of bacteria in South Asia and non-not those of Latin America, researchers have discovered.

That cases of cholera have been confirmed for the first in the province of Artibonite of Haiti on 19 October, the epidemic killed more than 2,000 people. Public health leaders many believe that spread of the disease has not yet reached a peak.

Human activity from a "remote" geographical source is likely how the epidemic began, researchers in the New England Journal of Medicine number Thursday online report.

"Our data distinguished Haitian strains circulating in Latin America and the Gulf Coast to the United States and therefore do not support the hypothesis that Haitian strain stemmed from the aquatic environment local" concluded Matthew Waldor, Professor of medicine at Harvard Medical School and his co-authors.

"It is therefore unlikely that weather conditions led to the Haitian epidemic, as had been suggested other epidemics of cholera."

The location and time of the outbreak has coincided with the arrival of peacekeepers from the Nations United South Asia, leading to speculation that disease was carried out by the troops of the Nepal.

But researchers warn that determine more precisely the source of the Haitian strain will require further investigation.

The new report is compatible with the Nepalese hypothesis, but Waldor noted that they did not compare with those of the Nepal Haitian samples or test Nepalese troops in Haiti.

Waldor said its report is consistent with the hypothesis Nepalese soldiers, but did not prove or deal with it directly. The researchers did not compare with those of the Nepal Haitian samples or test Nepalese troops in Haiti, he noted.

To identify the probable origin of the strain, the scientists used a new method for sequencing DNA and imaging to watch natural to synthesize a strand of DNA and track changes in enzyme technology.

Analysis has shown a relationship between samples Haitian and pandemic strains isolated in Bangladesh in 2002 and 2008.

Authors of the study "the Haitian epidemic is probably due to the introduction, by human activity, from a distant geographical source V. cholerae strain," wrote.

To hatch, Haiti has been free of cholera for a hundred years.

The results are similar to an earlier report by the Centers for Disease Control and Prevention based on older technology.

Based on the latest discoveries, Waldor and his co-authors suggest that a campaign of vaccination against cholera could not only control the disease, but reduce the spread of the strong strain than the island of Hispaniola, Haiti shares with Dominican Republic.

To reduce the spread, Waldor suggests troops or humanitarian workers in a country where cholera is endemic should take preventive measures - such as routine testing of disease and giving antibiotics or a dose of the vaccine - until they are sent to disaster areas.

The research was funded by the U.S. National Institute of Allergy and Infectious Diseases.

Files from the Associated Press