U.N. officials are labeling as inconclusive a French doctor’s report that Haiti’s cholera epidemic probably originated with U.N. peacekeepers from Nepal.

U.N. spokesman Vincenzo Pugliese said the report by French epidemiologist Dr. Renaud Piarroux fails to deliver definitive proof, CNN reported Wednesday.

“We have not dismissed the report but we have not accepted it completely,” Pugliese said. “We remain open to investigating this and we will get to the bottom of it.”

Piarroux ruled out a number of potential causes when he said the strain of cholera that has killed more than 2,000 in Haiti may have originated with U.N. peacekeepers from Nepal.

He noted that the first cases of cholera were reported just days after a battalion of soldiers arrived from Kathmandu, Nepal, on Oct. 8 and 12.

At the time, Kathmandu was experiencing a cholera outbreak but doctors said none of the arriving soldiers had symptoms of the disease.

Dr. Eric Mintz of the U.S. Centers for Disease Control and Prevention said international researchers are investigating the cause of Haiti’s cholera outbreak.

Worms are damaging the patient’s gut, researchers say, triggering a healing effect in areas affected by ulcerative colitis. STORY HIGHLIGHTS

• Man’s experience treating himself with parasitic worms published in a medical journal
• Experimental treatment for ulcerative colitis condemned by some as irresponsible
• Researcher: Conclusion is that worms "were able to restore mucus production in his gut"
• "Sometimes you really do have to take matters into your own hands," patient says

(CNN) — One day in 2004, a 29-year-old man with a terrible stomach problem stepped off a plane from the United States in Thailand. he wasn’t there for the sights, or the food, or the beaches. he had traveled thousands of miles for worms — parasitic worms whose eggs he intended to swallow by the thousands.

His doctor back home had told him his idea was crazy, that infesting himself with parasitic worms wouldn’t do anything to help his ulcerative colitis, and in fact could make him very sick. the gastroenterologist had told the man if he pursued this course of treatment, he would refuse to be his doctor anymore.

"You’ll be on your own," the man remembers the doctor telling him.

Indeed, he was on his own, standing in the office of a Thai doctor, asking her to pick the worm eggs out of an 11-year-old girl’s stool.

Ten to 15 bloody bowel movements a day

This month, the man’s experience treating himself with parasitic worms was published in a medical journal. Depending on who’s telling the story, his journey is one of a brilliant, empowered patient who found an amazingly effective treatment for himself and possibly others who suffer the same debilitating disease — or the dangerous tale of an irresponsible medical rebel who could have killed himself and, by telling his story, might be inspiring others to do the same thing. as with any experimental treatment, you should not try this at home.

The man — who wants to protect his privacy, and be referred to only as "the patient" — was 28 when he started having bloody bowel movements. Soon, he was having 10 to 15 bloody bowel movements a day.

"I was constantly running to the bathroom," he remembers.

Diagnosed with ulcerative colitis, nothing helped except high doses of steroids, which because of severe side effects, he could take only for limited periods of time. Soon, the patient became so sick he had to quit his job.

How to get the best medical care Elizabeth Cohen on her new book

His gastroenterologist wanted to admit him to the hospital for an intravenous round of cyclosporine, a potentially helpful yet dangerous medicine that depresses the body’s immune system and can increase the risk for getting cancer later in life.

If the cyclosporine didn’t work — and there was a 50 percent chance it wouldn’t — the doctor said his last hope was to remove his colon entirely, an extreme measure that would cause him to have to have a colostomy bag attached to him for the rest of his life to collect his stool.

"I was really at the end of the road," he says.

Meanwhile, the patient had gone on the internet and found an article in a medical journal by Dr. Joel Weinstock, chief of gastroenterology at Tufts University Medical School, which showed some ulcerative colitis patients found relief after ingesting the trichuris suis worm, a parasite that lives in the intestines of pigs.

The patient contacted Weinstock to ask him to treat him with worms, but Weinstock said no, since it wasn’t approved for general use by the Food and Drug Administration and could only be done experimentally.

Other doctors also told him no.

"One very famous parasitologist in New York told me he had patients who were immigrants, and he could get the eggs from their stool," he says. "but he told me for legal reasons he couldn’t do it. I understood completely. what if something went wrong and I died? He’d be blamed."

The patient became more and more convinced worms could help him. behind Weinstock’s study was this observation: Inflammatory bowel diseases such as ulcerative colitis affect nearly one in 250 people in the United States, but are extremely rare in underdeveloped parts of the world, such as sub-Saharan Africa.

Some experts believe parasitic worms might be part of the reason. when underdeveloped areas become developed, parasitic worms, also called helminths, become less common, and diseases such as ulcerative colitis become more common.

"We’re not exposed now to helminths in places like the United States, and that probably has an impact," Weinstock says. "We’ve tried to separate ourselves from our natural environment with our sterile water and our sterile food, and that’s saved lives, but there are negative consequences."

A ‘terrible choice’

"I was facing a terrible choice," the patient remembers, between going with the doctor’s treatment idea, which he really didn’t want to do, and looking outside the United States for worm eggs to ingest.

He contacted researchers in various developing countries to ask if they could help him get his hands on some eggs. the researcher in Thailand was particularly helpful, and he got on a plane to visit with her.

After he arrived, the doctor in Thailand extracted roundworm eggs from the stool of an 11-year-old infected girl. She gave the trichuris trichiura eggs to the patient, but he now faced another hurdle. the eggs needed to be cleaned in case the girl had hepatitis or some other infectious disease, and the eggs needed to mature for them to be helpful. It was up to him to clean the eggs and grow them in a process called "embryonation."

"there wasn’t much guidance on how to do it, since most people are trying to destroy these worms, not grow them," he says.

But he managed to do it and ingested first a dose of 500 eggs and then another of 1,000. the worms could live in his intestinal tract for many years.

Three months later he had fewer bloody bowel movements, and soon, none at all. his bowel movements were normal. he felt fine.

From time to time, when his ulcerative colitis would flare up again, he’d extract eggs from his own stool, and clean, embryonate and ingest them. again, his symptoms would go away.

A reluctant researcher

By 2007, having made so much progress, the patient wanted to document his journey scientifically, and he contacted various researchers to help him, including P’ng Loke, who was then a postdoctoral fellow in immunology at the University of California-San Francisco.

"he e-mailed me, and I ignored it," Loke remembers. "I was very skeptical at first, but he convinced me to have lunch with him."

At their meeting, the patient laid out his story in more detail, and Loke became fascinated.

"It’s an amazing story, and he’s quite possibly one of the smartest people I know," he says.

By the end of their meeting, they’d started to hatch a plan: Loke and his team would do colonoscopies to track the patient’s ulcerative colitis and look for the presence of worms in his colon.

The researcher, now an assistant professor of medical parasitology at New York University Langone Medical Center, and his team did a colonoscopy on the patient, which revealed an abundance of worms and no signs of ulcerative colitis.

When the patient suffered a flare-up of his disease in 2008, a colonoscopy showed fewer worms and typical signs of ulcerative colitis.

When he ingested more eggs, a third colonoscopy showed the colitis was once again in remission.

The study was published in this month’s Science Translational Medicine.

Why worms might work

To figure out why the worms seemed to be having this beneficial effect, Loke and his colleagues took a close look at the patient’s immune system after he ingested the worm eggs. after ingestion, he had an abundance of cells that produce a protein called interleukin-22, which is important in healing the mucosal lining of the intestines.

"Our main conclusion is that the worms were able to restore mucus production in his gut," Loke says, adding that the mucus lining protects the intestines from harmful bacteria.

But others are not so convinced.

"the impact of mucus alone is not a scientific explanation for the possible improvement attributed to the worms," says Dr. Stephen Hanauer, a member of the board of trustees of the American College of Gastroenterology.

Charges of irresponsibility

Hanauer, chief of gastroenterology, hepatology and nutrition at the University of Chicago, warned against making too many conclusions from one man’s positive experience with worms.

"We don’t make medical recommendations based on a single case report," he says.

He says New York University was "irresponsible" for putting out a press release about the study, and criticized media outlets such as CNN for reporting on it.

"It’s ridiculous and incredibly inappropriate," he says. "You’re driving people to go on the internet and buy these worms, and these are potentially pathogenic organisms. these eggs can invade the systems of people who are immune suppressed and cause infections."

Loke says he and his team pointed out in the press release that the worms might hurt some people rather than help them.

"I agree no one should be trying to change their treatment" based on the paper’s findings, Loke says.

The patient says he is also concerned others might try to copy him with potentially disastrous results, and so declined to explain exactly how he cleaned and embryonated the eggs.

He says he knows he took a risk by ingesting the eggs from a young girl in Thailand, but for him it was a better option than treatment with drugs that have potentially dangerous side effects, or the removal of his colon.

"Sometimes you really do have to take matters into your own hands," he says.

a Nepalese U.N. peacekeeper helps a woman to carry a tarp and a kitchen set in February. STORY HIGHLIGHTS

• NEW: French doctor says "massive contamination" of river caused the epidemic
• Epidemiologist’s report suggests Nepalese soldiers may have been the starting point
• United Nations has not dismissed the report, but "not accepted it completely" either
• CDC: "No evidence whatsoever that would suggest" the strain is unique to Nepal

Port-Au-Prince, Haiti (CNN) — a French doctor’s report suggests that the strain of cholera ravaging Haiti may have originated with U.N. peacekeepers from Nepal, but U.N. officials and others cautioned that the report was inconclusive.

The report by French epidemiologist Dr. Renaud Piarroux rules out a number of potential causes and points to the Nepalese soldiers as the most probable, said Vincenzo Pugliese, spokesman for the U.N. mission in Haiti, but it fails to deliver definitive proof.

"we have not dismissed the report but we have not accepted it completely," he said. "we remain open to investigating this and we will get to the bottom of it."

The Centers for Disease Control and Prevention’s Dr. Eric Mintz said research seeking the origin of the deadly outbreak — the death toll has now topped 2,000 since the first case was reported in mid-October — is being undertaken around the world.

"to date, I am aware of no evidence whatsoever that would suggest the strain in Haiti is unique to Nepal," Mintz said. "by the tests we have done here so far, this strain is indistinguishable from strains that have been seen in other countries in South Asia. Vibrio cholerae strains do not get their passports stamped when they cross an international border, and there are many strains in circulation around the globe at any given time."

The first case was reported October 14 in the north of the country, near a camp of Nepalese peacekeepers, but Pugliese said he was unaware that Piarroux had ever visited the camp. more than 90,000 people have been sickened by the water-borne disease, according to Haiti’s Ministry of Public Health.

In his report, Piarroux — who said his investigation lasted from November 7-27 — said the first cases came from residents living near the Artibonite River and that many of the early victims were getting their water from that river or its tributaries, downriver from the U.N. peacekeeper camp.

At one village, Piarroux said, residents told his team of pipes running from the camp to the river and that a nauseating substance flowed through the pipes. the residents said that military people removed the pipes, which they said came from a septic tank in the camp.

Doctors from the U.N. mission tested the latrines at the base on October 21, but the tests were negative for cholera, he said. the doctors told him the tests were conducted while the pipes were open.

"But it’s impossible to know if the septic tank or the pipes had been disinfected before the samples were taken," Piarroux wrote.

Piarroux noted the first cases of cholera were reported just days after a new battalion of soldiers arrived from Kathmandu, Nepal, on October 8 and 12. Kathmandu was experiencing a cholera outbreak at the time, he said, but doctors said none of the soldiers came forward with symptoms and that none of the samples collected from the camp registered positive for cholera.

Piarroux, however, urged caution in accepting those reports and suggested officials could have taken measures to erase any trace of cholera.

While the epidemic began near the camp along the Artibonite tributary, Piarroux wrote, "massive contamination" of the river and its delta caused an explosion of the disease. Cases of the disease follow downriver in succession, he said, notably on October 19, when six communities 100 kilometers away from the initial outbreak — all downriver — experienced outbreaks.

"This massive and widespread contamination across the entire delta and region of the Artibonite could only have been started by dumping a phenomenal amount of fecal material from infected people all at once," he wrote.

And from those areas, he said, infected people carried the disease to other villages, where human-to-human transmission took place.

Haiti was already reeling from the devastating 7.0 magnitude earthquake that hit the island nation on January 12, killing more than 220,000 dead, injuring more than 300,000 and leaving more than 1 million homeless. last month, Hurricane Tomas brushed the island, dumping torrents of rain.

Piarroux’s expert report was submitted to the French Foreign Ministry, which said it had received the report and sent it on to the United Nations and the Haitian government. the Haitian government, however, said it had not seen the study.

Several aid workers said they were concerned about the report’s suggestions, given Haiti’s currently volatile situation and stress that it is inclusive. Pugliese said the publicity surrounding the report was "a point of concern" that more violence against the peacekeepers could erupt as Haiti was already tense amid the pending announcement of election results, expected sometime Tuesday evening.

Stefano Zannini, head of the Haiti mission for Medecins Sans Frontiers (Doctors Without Borders) said the stir over the cholera outbreak’s origins was not as important as the battle against the intestinal disease.

"One person is dying every 30 minutes in Haiti," Zannini said. "Knowing the origin of the epidemic has no impact on saving lives."

CNN’s Moni Basu, Jim Spellman and Miriam Falco contributed to this report.