A man suffering cholera symptoms is pushed in a wheelbarrow to St. Catherine hospital, run by Doctors Without Borders, in the Cite Soleil slum in Port-au-Prince on Friday. (Emilio Morenatti/Associated Press)The United Nations resumed aid distribution in northern Haiti on Saturday to help cholera victims as protests linked to the rumoured source of the outbreak subsided.

Violent demonstrations erupted last Monday and continued throughout the week in Cap-Haitien, as some Haitians blamed UN peacekeepers for the outbreak. The protests spread to the capital, Port-au-Prince, on Thursday.

At one treatment centre in Cap-Haitien, medical aid was all but shut off from those who needed it most during the violence, but humanitarian workers reported calmer streets on the weekend.

"What the violence in Cap-Haitien did was stop the operations to counter the cholera," said Nigel Fisher, the UN humanitarian co-ordinator based in Port-au-Prince. "We had a warehouse burned, which had water sanitation and food supplies in it, so we called for calm because people were dying because of those demonstrations.

"So it's calmer now today in Cap-Haitien and I'm recommending to our humanitarian workers that we can start operations again."

Earlier in the week, several hundred protesters threw rocks at a Nepalese unit of UN troops that has been blamed for introducing the virulent strain of cholera, matching one found in South Asia.

Fisher said the UN has found no evidence to support the allegation. The outbreak began in the central town of Hinche, where there is a Nepalese garrison, he said.

"There has been extensive testing, but so far the link with the Nepalese garrison has not been proven."

Rumours have been circulating for weeks that the outbreak began because septic tanks at a base for more than 400 Nepalese UN peacekeepers leaked along the Meille River, which feeds into the Artibonite River.

The waterborne disease has killed more than 1,100 people in Haiti. Roughly 18,000 have sought medical treatment for the bacterial infection, with symptoms of diarrhea, vomiting and fever.

Officials worry the outbreak could overwhelm Haiti as it struggles to recover from last January's earthquake, which killed 250,000 people and left more than a million homeless.