Registered nurse Jane Noble of Grimsby, Ont., cares for a cholera patient at a Samaritan's Purse clinic in Haiti in this Nov. 26 photo. ((Roseann Dennery/Canadian Press))

A contingent of UN peacekeepers is the likely source of a cholera outbreak in Haiti that has killed more than 2,000 people, a French scientist said in a report obtained Tuesday by The Associated Press.

Epidemiologist Renaud Piarroux, who studied the outbreak for the Haitian and French governments, concluded that there was no doubt that the cholera originated in contaminated water next to a UN base outside the town of Mirebalais along a tributary to Haiti's Artibonite river.

"No other hypothesis could be found to explain the outbreak of a cholera epidemic in this village ... not affected by the earthquake earlier this year and located dozens of kilometres from the coast and (quake refugee tent) camps," he wrote in a report that has not yet been publicly released.

The AP obtained a copy from an international official who released it on condition of anonymity. Piarroux declined in an e-mail interview to discuss his findings.

The French Foreign Ministry confirmed that Dr. Renaud Piarroux's report has been completed and sent to officials in Haiti and at the United Nations. France commmissioned the report at Haiti's request.

The report calls for a further investigation of the outbreak and improved medical surveillance and sanitation procedures for UN peacekeeping troops.

Anger sparked riots

Many Haitians suspect that the Nepalese troops were the source of the outbreak, and anger at the troops sparked a week of violent riots, but the French scientist's report is the first scientific study linking the base to cholera.

Piarroux said in his report that he cannot prove there was cholera inside the base. But he also said that septic tanks and pipes that would have helped to confirm the presence of the bacteria were no longer at the base when he visited.

Nepalese troops earlier confirmed they had replaced a leaking pipe, which contained a foul-smelling run-off that the UN denies was human waste, between two visits by an AP reporter in October.

The U.S. Centers for Disease Control and Prevention earlier confirmed that the strain of cholera bacteria in Haiti matched one from South Asia, a region that includes Nepal, but the UN denied its troops were to blame and said it was more important to focus on fighting the outbreak than on its origin.

UN officials said Tuesday there is still no conclusive evidence that the peacekeepers caused the infection.

"We have neither accepted nor dismissed his findings, as it's one report among others," UN mission spokesman Vincenzo Pugliese said. "The Nepalese contingent in Mirebalais is just one piece of the cholera puzzle, since there is no conclusive evidence at this point that the Nepalese camp was or was not the source of the epidemic."

Since it emerged in late October, the disease has spread throughout much of the country and sickened at least 100,000 people. The UN says up to 650,000 people in Haiti could get cholera over the next six months.