The latest bombing of Iraq brings back vivid memories of the Gulf War now 10 years in the past. While the war may be long over, its effects linger in what is known as Gulf War syndrome. Martin Enserink reports on this mysterious ailment in the Feb. 2 issue of Science.

Enserink writes that every war seems to give rise to a variety of vague symptoms that include fatigue, headaches, sleep disturbances, memory loss, depression, and aches and pains in the muscles and joints. In the Civil War, it was called “soldier’s heart” and was attributed to carrying heavy backpacks. During World War I, it was called “effort syndrome” and was thought to be caused by the rigors of trench warfare. In World War II, it became “shell shock” brought on by the noise and concussions of exploding ordnance. Vietnam brought its “post-traumatic stress disorder” and “Agent Orange syndrome,” and finally came “Gulf War syndrome.” Whatever the war or the name given to the symptoms, the soldier’s complaints were generally vague, had no obvious cause and effect, and were largely ignored once the veterans returned home.

Enserink says the complaints of Gulf War veterans were similarly ignored until 1996, when it was learned that a huge munitions depot blown up by American forces contained stockpiles of the nerve gases sarin and cyclosarin. The outcry after the revelation that tens of thousands of troops may have been exposed to traces of nerve gas from the depot forced the Pentagon to take action.

The problem soon was complicated by mounting evidence that several factors in the Gulf War environment might be behind the troops’ complaints. There were widespread vaccinations against anthrax and botulism that are largely untried. Soldiers were ordered to take PB tablets to guard against gas attacks, but those may have been harmful. Others were exposed to depleted uranium used in “tank-busting” shells and fingered as the culprit in the “Balkan War syndrome” that afflicts many U.N. peacekeepers. Pesticides used to fight desert fleas and sand flies received their share of blame, as did the toxic smoke clouds from burning oil wells. Researchers were faced with the daunting task of matching environmental exposures to symptoms while trying to track down the causes of specific complaints.

The Department of Defense created a special office to coordinate its Gulf War illness activities along with the Department of Veterans Affairs. To date, more than $155 million has been spent on 200 different studies. So far, the studies have turned up a series of negatives indicating that Gulf War veterans do not die earlier, do not have children with greater numbers of birth defects, neither are they hospitalized more often than the general civilian population.

One massive study that showed no positive results involved 98,900 soldiers who may have been in the path of a toxic plume from the munitions depot. Another study attempted to find a link between vaccinations and the syndrome. The only researcher who claimed to have found a positive link between the syndrome’s symptoms and exposure was Robert Haley of the Texas Southwestern Medical Center. In fact, he identified three syndromes based on the type of exposure, but his work has been criticized for methodological problems, and subsequent researchers have been unable to duplicate his results.

Congress, under political pressure, has grown impatient with the lack of results. Christopher Shays, R-Conn., recently demanded to see “five different treatments within a year” while Bernie Sanders, an independent from Vermont, warns that funds may be stripped from the DOD and VA and awarded to independent researchers. Already three studies, which one scientist terms “fringe science,” have received direct congressional funding, circumventing the review process.

The largest of these was a $3.4 million grant to a retired physician in New Orleans to look for a link between a type of gram positive bacteria and soldiers’ illnesses. The only clue he had to make the link was that he had seen the same kinds of complaints from women who got infections from silicone breast implants. The doctor, Edward Hyman, has claimed success in curing sick soldiers with massive doses of antibiotics, but he has never published his results or kept any formal clinical trial records.

Others who have tried unsuccessfully to verify Hyman’s claims call his work fatally flawed. At the same time, many researchers have become increasingly skeptical that the true cause of Gulf War illnesses will ever be found.