WASHINGTON -- More than 1,000 Persian Gulf War veterans -- including several from Maryland -- may be infected with a blood parasite that can emerge decades from now to cause high fevers, extreme fatigue and diarrhea, according to a military doctor.
The disease, probably caused by the bite of a female sand fly, has been confirmed in only 11 Desert Storm veterans.
But Dr. Charles Oster, chief of infectious diseases at the Walter Reed Medical Center, said yesterday that unpublished Army research studies on two groups of seemingly healthy elite troops suggests that "hundreds" of other Gulf War veterans may have the infection without knowing it.
"We are probably only seeing the sickest of the people who are infected, and there are presumably another 10 to 100 times that number who have been infected with this organism but didn't get sick, or didn't get sick enough to get medical attention," Dr. Oster said. He based his judgment on research in the slums of Brazil on a similar parasitic illness.
Dr. Oster said such parasites can exist in a virtually harmless state for decades, and then cause major illness if the human immune system is suppressed by cancer chemotherapy, an organ transplant or contracting AIDS.
The Pentagon announced the existence of the Gulf War disease -- viscerotropic leishmaniasis -- last November. Since then it has reported "several hundred" other complaints from veterans complaining of unexplained flu-like symptoms. But an Army report last month attributed most of the complaints to "very high levels of stress."
One reason the military is rushing the tests, Dr. Oster said, is that researchers have not yet been able to rule out the possibility that soldiers could in rare cases transmit the leishmaniasis parasite through sexual relations.
One Army research study found a "cluster" of apparently healthy leishmaniasis carriers in the Army Foreign Materiel Intelligence Battalion, a unit of intelligence specialists from Aberdeen Proving Ground, Md.
Dr. Oster confirmed that "about 4 to 5 percent" of the roughly 200 active army soldiers in the Fort Bragg and Aberdeen units had been found to have some evidence of leishmaniasis infection, even though only two soldiers were showing disease symptoms. He said such blood tests aren't precise and are therefore not being offered on a large scale to other Desert Storm vets.
Another study focused on the 82d Airborne Division at Fort Bragg, N.C., after officials confirmed one of its members had the disease. Blood tests on about nine of the paratroopers showed evidence of exposure to the same parasites, even though most of the soldiers showed no sign of illness, Dr. Oster confirmed.
"I don't like to quote that because that test is no good," Dr. Oster said. "It may be alarmist on the one hand to suggest that 5 percent of our soldiers were infected. It may be conservative on the other hand. Maybe it is 10 percent [who] got infected. The point is we just don't know until we have better diagnostic tests."