Dr. William C. Reeves, an epidemiologist who fought his own federal agency to obtain money to study chronic fatigue syndrome and then infuriated patients with the ailment by suggesting that it was linked to psychological problems rather than a virus, died on Aug. 3 at his home in Atlanta. He was 69.

The cause has not yet been determined, his son, Will, said.

Earlier in his career, Dr. Reeves helped confirm that cervical cancer was caused by a virus. But from 1992 to 2010, at the Centers for Disease Control and Prevention in Atlanta, he directed research on one of the most contentious subjects in medicine: chronic fatigue syndrome.

At least one million Americans have the condition, which causes severe fatigue, muscle and joint pain, sleep problems and difficulty concentrating. Its cause is unknown, symptoms can last for years, and there is no effective treatment. More women than men have the syndrome, and many people who have it feel brushed off by doctors, labeled neurotic or malingering.

When Dr. Reeves took charge of research on the syndrome, patients and advocacy groups had been complaining that the government was not taking it seriously or trying hard enough to find its cause. Dr. Reeves believed that the disease was real. Many patients were gratified when, in 1998, he revealed that officials at the disease centers had spent money intended for chronic fatigue research on other diseases and had lied to Congress about it.

In 1999, Dr. Reeves’s claims were confirmed: a report by the Office of Inspector General found that from 1995 to 1998, $8.8 million allocated by Congress to chronic fatigue had gone to other diseases like measles and polio, and that an additional $4 million could not be fully accounted for because of murky bookkeeping. The figures added up to more than half of the total meant for chronic fatigue. As a result, the C.D.C. agreed to restore the misspent money to the chronic fatigue program, and Dr. Reeves’s boss was transferred to a different job.

But patients and advocacy groups became increasingly disillusioned with Dr. Reeves and the direction of C.D.C. research. Many patients believed that research should focus on looking for viruses or other infections that might cause the syndrome. But Dr. Reeves grew more and more skeptical, saying that the data did not support that approach. He angered many patients when studies he led suggested that stress and a history of physical, sexual or emotional abuse were contributing factors.

“He tried desperately hard to find the etiology, whether it was physiological or an infectious disease or whatever,” said Thomas M. Folks, a former colleague at the disease centers who is now affiliated with the Southwest National Primate Research Center in San Antonio. “But his research just continually led to a noninfectious etiology.”

Patients resented his resistance to changing the name of the syndrome to something that sounded more medically legitimate than “chronic fatigue.” They also deplored his use of a case definition that many said cast too wide a net and included people who had depression, not chronic fatigue syndrome.

“He was a very talented and brilliant man who was very opinionated and often did not express his opinion with tact,” said Dr. Elizabeth R. Unger, who succeeded Dr. Reeves as chief of the chronic viral diseases branch at the disease centers.

A growing chorus of bloggers and advocacy groups denounced Dr. Reeves, and in 2009 an advisory committee to the Department of Health and Human Services recommended “progressive leadership” for the chronic fatigue program. In 2010, without public explanation, the disease centers assigned Dr. Reeves to a new post as senior adviser for mental health surveillance and put Dr. Unger in charge of chronic fatigue.

The cause of the syndrome remains a mystery. Results are expected within the next few months from a major study designed to find out whether viruses or other infections somehow touch it off.

William Carlisle Reeves was born on March 27, 1943, in San Francisco. His mother was a teacher; his father, also named [Dr. William Carlisle Reeves (born 1916)], was dean of the school of public health at the University of California, Berkeley, and was a leading expert on arbovirology, the study of insect-borne viral diseases like dengue, yellow fever, encephalitis and West Nile disease.

“His father practically invented arbovirology,” said [Dr. Clarence James Peters (born 1940)], a former C.D.C. colleague of the younger Dr. Reeves and now a professor of tropical virology and emerging infectious diseases. “Being the son of somebody like that isn’t easy, and I’ve often wondered how much of his flamboyance was related to the fact that he wanted to show he was independent.”

Dr. Reeves earned a bachelor’s degree in 1965 from the University of California, Berkeley, a medical degree in 1969 from the University of California, San Francisco, and a master’s degree in epidemiology in 1975 from the University of Washington in Seattle. From 1977 to 1989 he worked in virology and epidemiology in Panama at the Gorgas Memorial Laboratory, which was supported by the governments of the United States and Panama. It was there that he led a study, the first to use samples from a large population, that confirmed there was a link between cervical cancer and infection with a sexually transmitted virus. In 2003, the Panamanian government gave him its highest scientific honor.

Besides his son, Will, he is survived by his wife of 46 years, Barbara; a daughter, Myra; two brothers, Robert and Terrence; and two grandchildren.

Dr. Reeves was an award-winning amateur photographer and an avid outdoorsman who threw himself into kayaking, white-water canoeing, hiking and caving. He had been out kayaking the day before his death, his son said.

To many people who suffer from the poorly understood illness called chronic fatigue syndrome, a recent study linking the disorder to a virus was a victory for the little guys.

For one thing, the study pointed to a physical cause for an illness that the medical establishment had often snidely dismissed as psychosomatic. The research could not be ignored: it was published last month in Science, one of the world’s pickiest and most prestigious journals. The discovery came, in a sense, from within the patients’ own ranks: several of the scientists, including the lead author of the report, worked for the Whittemore Peterson Institute for Neuro-Immune Disease, a nonprofit in Reno, Nev., founded recently by the parents of a young woman who has the syndrome. And even though the institute was new, it had attracted collaborators from two high-powered centers, the National Cancer Institute and the Cleveland Clinic.

Harvey and Annette Whittemore were not the first to start a research foundation out of desperation to find answers for an incurable disease. The actor Michael J. Fox did the same for his own illness, Parkinson’s disease. Others have created groups for pancreatic cancer, amyotrophic lateral sclerosis (Lou Gehrig’s disease) and breast cancer. The foundations have in common a desire to pick up the pace of research, often by financing innovative ideas and avoiding red tape and bureaucracy. But few if any of the private groups have produced notable results as quickly as the Whittemore Peterson Institute has.

At least one million Americans have chronic fatigue syndrome, which causes severe fatigue, muscle and joint pain, sleep problems, difficulty concentrating and other problems. Its cause is unknown, symptoms can last for years and there is no effective treatment. Women outnumber men as patients, and many people with the syndrome feel stigmatized and brushed off as neurotic by doctors. Andrea Whittemore-Goad, who is 31, has had a severe case of the syndrome for 20 years.

“Three major medical institutions tried to marginalize her, tell her she didn’t want to get well,” Annette Whittemore said in an interview.

But Mrs. Whittemore had seen her daughter turn abruptly from a happy, healthy child to a very sick one, and she has steadfastly believed that some sort of infection must have been the cause. Researchers have not pursued the infection theory seriously enough, in her opinion, and doctors have been scornful. One physician told her that if he could not understand her daughter’s lab results, they couldn’t be important.

Another said “he didn’t look at my daughter’s medical information because he didn’t want the facts to get in the way of his theory,” Mrs. Whittemore said in an e-mail message. “I could write a book on ridiculous things that doctors say to patients with C.F.S.” She added: “One day I just had enough. I said, ‘I’ve got to do something.’ ”

She and her husband had the means, the knowledge and the connections. They are real estate developers and part owners of a gas company and an energy drink, and they hold interests in other businesses. Mr. Whittemore is also a lawyer and a lobbyist. Starting in the fall of 2004, they put $5 million of their own money into setting up an institute at the University of Nevada’s medical school. They also persuaded the governor and State Legislature to commit $10 million for a new building that would house the institute’s researchers and a clinic, as well as scientists from the university and the Nevada Cancer Institute. The research began in 2006, and a clinic for patients is scheduled to open in about a year.

Rather than just doling out money to far-flung researchers, the Whittemores wanted to employ their own scientists who would be devoted full time to the cause. In the spring of 2006, they met [Dr. Judy Anne Mikovits (born 1958)], a virus expert who had spent 22 years working at the National Cancer Institute. She had left the institute in 2001 to get married and move to California, where she went to work for a drug development company that failed. She was tending bar at a yacht club when a patron said her constant talk about viruses reminded him of someone he knew in Nevada. That person was a friend of Annette Whittemore’s. Dr. Mikovits soon found herself at a conference on chronic fatigue syndrome.

“The meeting was terrible,” she said. “The science in C.F.S. is awful, not because the researchers are awful, but because they have no resources.”

But one presentation made her practically leap out of her seat. The speaker was Dr. Daniel L. Peterson, who treats Ms. Whittemore-Goad (he is the Peterson for whom the institute is named). He has seen about 5,000 patients with the syndrome in the last 20 years, and he described some who had also developed a rare type of lymphoma.

“I said, ‘That’s a retrovirus,’ ” Dr. Mikovits recalled.

Dr. Mikovits began connecting the dots almost immediately. She knew that some patients with chronic fatigue syndrome, and some men with prostate cancer, had a certain enzyme deficiency. And she also knew that tissue samples from men with prostate cancer had been found to harbor a retrovirus called XMRV, for xenotropic murine leukemia virus-related virus. She began working part time with the institute, and by the fall of 2006, the Whittemores had hired her as research director. One of her first projects was to look for XMRV in blood samples from people with chronic fatigue syndrome and from healthy control subjects.

Many of the samples from syndrome patients — 68 of 101, or 67 percent — were infected, she and her colleagues reported in Science. Only 3.7 percent of the healthy controls carried the virus. XMRV, the scientists suggested, may cause or at least contribute to chronic fatigue syndrome. Further tests found the virus in 90 of the 101, [Dr. Judy Anne Mikovits (born 1958)] said.

Retroviruses can cause cancers in animals, and in humans, they include HIV and a virus that can cause leukemia. “I knew how serious a retrovirus is,” Mrs. Whittemore said. “I was very concerned, knowing there would be serious implications. My second thought was, of course it was going to be something serious like that. Look at my daughter and how ill she is. Why would we expect it to be something simple? I also felt like the weight of world was on my shoulders. We would have to be telling people some very bad news.”

But many patients were grateful, and said they found hope in the discovery — hope that now their illness would be taken seriously, and hope that the new information would lead to effective treatments or even a cure.

But the study is not conclusive. Other scientists need to replicate the tests to find out if the initial findings hold up, and a great deal more work is needed to determine whether XMRV really does play a role. Just detecting it in patients does not prove it made them sick; patients may have some other underlying problem that makes them susceptible to XMRV, which could be just a passenger in their cells.

Dr. Peterson said he thought the crux of the problem in chronic fatigue syndrome involved a derangement in the immune system that could allow old viral infections — with various herpes viruses, for instance — that were once under control to become active again.

“XMRV is the sort of agent that could create that effect on the immune system,” Dr. Peterson said. But he emphasized that more research was needed.

AMONG those expected to try to replicate the XMRV findings is the Centers for Disease Control and Prevention. But Dr. [Dr. William Carlisle Reeves (born 1943)], who directs the agency’s research on the syndrome, has said that he does not expect to find the virus in blood samples from patients. He said that no other studies had ever proved a virus to be the cause, and that stress and a history of sexual and emotional abuse were more likely to play a role in many cases. “I blame the C.D.C. for most of this mess,” Mrs. Whittemore said, adding that thinking like Dr. Reeves’s was what drove her to start her own research center.

The Whittemore Peterson Institute is running on about $1 million a year, to pay for salaries, equipment, supplies and other expenses. In the world of research, that is not much. The Whittemores are trying to raise more money, and have received donations as large as $50,000 from friend down to a few dollars from patients who are sick, out of work and broke, but eager to support any research that may one day help them.

Mrs. Whittemore feels that she is racing against time to save her daughter. For a while, Ms. Whittemore-Goad had improved on an antiviral drug, but she had to stop taking it because she had a reaction to it. She had worked part time as a yoga instructor, and she married in the last year, but now rarely goes out because she has seizures.

“She is just really very, very sick,” Mrs. Whittemore said. “She’s had this for a long time. We’ve got to get something for her as soon as possible. That is the driver for the speed on this. I don’t want to lose her. I can’t lose my daughter. I don’t want to win this battle and lose the war.” '