Aid groups in Haiti were cautiously optimistic Sunday that they have contained a cholera outbreak that has killed more than 250 people and kept it from spreading into crowded displacement camps, home to hundreds of thousands of earthquake survivors.

UN officials said Sunday there have been 3,015 reported cases of the disease, which is spread through bacteria in contaminated water.

The outbreak has been contained in the Artibonite region north of Port-au-Prince. But at least five people who travelled from Artibonite to the Haitian capital have tested positive for the disease.

Sabrina Pourmand Nolan, a staff member of the aid group World Vision, says there have been no new cases of cholera in Port-au-Prince since and no sign of the potentially deadly disease in the overcrowded camps that surround the city.

"We have no new cases of individuals who have been in Port-au-Prince over the last week and contracted the disease," she told CTV News Channel. "So that's positive at the moment."

"However we assume that some of those individuals who have cholera in Port-au-Prince could have come into contact with other people. That's why we are continuing to prepare."

Government officials voiced hope Sunday that the deadly bacterial disease could be confined to the rural areas where the outbreak originated last week.

"It's not difficult to prevent the spread to Port-au-Prince. We can prevent it," said Health Ministry director Gabriel Timothee.

He said tightly limiting movement of patients and careful disposal of bodies should fend off the disease from hitting the camps in Port-au-Prince, home to about 1.3 million earthquake survivors.

Claude Surena, president of the Haiti Medical Association, said that would be a major medical disaster.

"The worst case would be that we have hundreds of thousands of people getting sick at the same time," said Surena.

In a promising development, the aid group Partners in Health said fewer and fewer patients were being hospitalized in the city at the centre of the initial outbreak. Just 300 patients were hospitalized in St. Marc on Saturday, a number that has decreased by the end of each day.

"In a way, it couldn't have happened at a better moment than now because everyone is on the field -- lots of (aid organizations), lots of money. We haven't had any hurricanes so far this fall but people are here, and people are prepared," said Marc Paquette, Haiti director for the Canadian branch of Medecins du Monde.

Cholera is a water-borne disease, but can also be spread by contact with infected individuals or food and also through contaminated latrines, she said.

Pourmand Nolan said aid workers have been encouraging camp residents to wash their hands as often as possible, clean their latrines out regularly and have been treating the camps' water supply with chlorine.

"Prevention is the way to go. We are in the camps daily telling individuals that this can be prevented and here's how," she said. "We need to continue bracing for challenging weeks ahead."

There have been several confirmed cases in small towns around the capital and an unconfirmed report that a young girl contracted the disease in a southern district of Port-au-Prince.

At least five new cases were reported in a town called Arcahaie, which is about 50 kilometres from the capital. Another four cases have been identified in Limbe, a small northern municipality.

There have also been confirmed cases at a prison north of the capital, said Health Ministry director Gabriel Thimothe.

Cholera can lead to vomiting and diarrhea, which can cause dehydration and death in a matter of hours.

Sophie Chavanel of the Canadian Red Cross said the organization has been sending convoys of trucks up to Artibonite for the past two days. Eight trucks have so far arrived carrying badly needed supplies ranging from water and antibiotics to tents and mattresses, all of which have been distributed to local hospitals and health clinics.

Chavanel said the organization also continues to distribute about 2 million litres of water each day, which it has done since the January quake.

With files from The Associated Press