A cholera outbreak showed signs of easing Monday after killing more than 250 people in a sweep through rural Haiti, but experts warned that the earthquake-devastated country's first bout with the disease in decades is far from over.

Aid groups were joining the government in a race to purify water and warn people throughout the countryside and the capital, Port-au-Prince, where the Jan. 12 earthquake left more than a million survivors in squalid stick-and-tarp camps that are ripe for the waterborne disease.

"The worst part is over, but you can always have a new spike of cholera," said Health Ministry Director Gabriel Timothee. He said the situation is beginning to stabilize with only six new deaths reported since Sunday.

Haiti, which had not suffered a cholera outbreak in at least 50 years, is the latest developing country to be afflicted by the disease that sickens an estimated 3 million to 5 million people a year and kills 100,000.

It is common in regions such as the Indian subcontinent and sub-Saharan Africa — an outbreak in Nigeria this year killed at least 1,500 people, according to the United Nations — but it has been rare in industrialized nations for the past 100 years.

The disease, spread through feces-contaminated drinking water or food, leads to vomiting and watery diarrhea which, if not treated, can kill a person within hours. It is preventable with clean water and sanitation, but both can be hard to find in corners of the Western Hemisphere's poorest country.

Some of the 1.3 million people living in the capital's tent camps already fear the worst.

"I'm afraid because the water we're drinking here is not treated properly. Any time I drink the water it makes my stomach sick," said Joseph Sidsen Guerry, 20, who lives in the small Jeremie camp in central Port-au-Prince.

Health groups working to keep the disease from spreading beyond the central valley where it emerged last week are focusing on treating the ill, strengthening medical centers with isolation wards and educating the public about the disease.

"The biggest challenge for us is the amount of misinformation," said Julie Schindall of Oxfam, which trained the host of a radio call-in program to promote good hygiene practices in rural Petit Riviere near the outbreak's epicenter in the Arbitonite region. "We have to make sure they know what is true and what is not true."

Schindall said some Haitians were still drinking from the contaminated Artibonite river because others did so without getting sick.

Water purification tablets and oral rehydration salts — used to counteract potentially lethal dehydration caused by diarrhea — have been widely distributed in the region where the river or rainwater remain the only water source for many, said Louise Ivers, an official with the aid group Partners in Health.

For now, officials say their efforts have been making gains.

Timothee said at least 259 people have died since early last week and more than 3,300 have fallen ill, but he emphasized that no cases had been confirmed as originating in the crowded capital. Five patients were diagnosed with cholera in Port-au-Prince over the weekend, but officials said they got sick elsewhere.

Michel Thieren, a program management officer for the Pan-American Health Organization, said the outbreak has been largely confined to the Aribitonite. But he warned: "We are expecting a gradual spreading of cholera in the country, and the way it will do that is still unpredictable."

Aid groups stress that community outreach is a key part of their prevention efforts.

The California-based International Medical Corps has enlisted Haiti's Boy Scouts to distribute fliers educating people about proper hygiene, spokeswoman Margaret Aguirre said. Her group also was dispatching mobile teams of doctors and nurses equipped with IV fluids, "cholera cots" with a hole for human waste, and disinfectant.

Experts said the disease is likely to spread eventually to the Dominican Republic, which is on the same Caribbean island as Haiti.

"Now that cholera has established itself with a strong foothold in Haiti, it probably will not go away for several years," said Dr. Jon K. Andrus, PAHO's deputy director.

Cholera is not a major threat in countries such as the United States because of advanced water and sanitation systems. On average, only about seven cases a year are reported in the U.S., and they almost always involve a traveler infected in another country.

Cholera has played a central role in the development of the field of public health: A cholera outbreak in London in 1854 was successfully battled by a London physician, Dr. John Snow, who helped lay to rest the long-held theory that the disease is caused by miasma, or foul-smelling air.

Snow deduced that polluted water coming from a Broad Street pump was the source of illness.He is considered the father of the disease investigation field known as epidemiology.