WASHINGTON -- Worried soldiers have inundated military hospitals with questions about a rare parasitic disease they may have brought home from the Persian Gulf war, but doctors say they can only provide partial answers because they don't know exactly what they're dealing with.
Seven of 22 confirmed cases appear to involve a new, undocumented form of a mild, non-fatal illness caused by a parasite and called leishmania tropica, a discovery that led to last week's decision by the Pentagon and civilian blood banks to stop accepting blood donations from anyone who went to the gulf region on or after Aug. 1, 1990.
"We've had quite a number of calls, particularly at Fort Bragg [in North Carolina] where they were deluged with calls," said Virginia Stephanakis, spokeswoman for the Army surgeon general's office. "It's created a lot of anxiety."
Maryland-based Army and Navy medical facilities, including Kimbrough Army Hospital at Fort Meade, logged few inquiries, apparently because most callers from the state sought out Walter Reed Medical Center in Washington for information, officials said. A spokesman there reported about 200 calls within a day of the announcement of the blood donation ban.
"I think there's worry and concern all over," observed Marla Jones of the Army Health Services Command at Fort Sam Houston, Texas. "Almost every military post had some people in the gulf."
But, she said, "the chances of somebody getting this are very, very remote."
Army Brig. Gen. Ronald Blanck, chief of professional services for the Army surgeon general, said he hoped the effort to protect blood supplies from contamination would not arouse public fear, even though he acknowledged that the parasitic disease leishmaniasis may pose a serious health threat to people with weakened immune systems or cancer and to transplant patients who require frequent blood transfusions.
The disease is not contagious in person-to-person contact, military doctors said.
General Blanck played down the risk of contamination by blood transfusion and described the ban on blood donations as a needed precaution until a simple screening test could be developed. For now, time-consuming blood and bone marrow tests are available only at Walter Reed Medical Center.
None of the 22 soldiers who became ill donated blood after returning from the gulf, and General Blanck said the amount of actual contamination of the blood supply is believed to be "very, very low."
While doctors expressed confidence that the illness would not become widespread, they conceded that researchers had no idea how prevalent the disease might be among returning war veterans.
The parasite usually is transmitted by the bite of a tiny sandfly, which could easily escape a person's notice, and the incubation period "is in the order of months," said Army Col. Charles Oster, chief of infectious disease at Walter Reed. A more "visceral" leishmaniasis, which enters the bone marrow or organs, can have prolonged incubation periods of one to two years, he said.
An unclassified Army memorandum, sent last week to various military health commands, the Centers for Disease Control and the Food and Drug Administration, said anyone who was stationed in the gulf should be "considered at risk of exposure" because "risk factors" for the disease "are not well defined at this time."
For this reason, the blood ban was extended to all 541,425 active-duty and reserve personnel, plus unknown numbers of civilians, who visited any of eight gulf states before and during the war -- even though the 22 known cases of leishmaniasis involved only Army troops deployed to southern Iraq, Kuwait, northeastern Saudi Arabia and the Saudi cities of Dhahran and Riyadh.
Referring to the seven specific cases that have puzzled doctors and researchers, the Army memo reported, "The natural history of this . . . form of L. tropica is not known."
"It's a mystery," Colonel Oster said. "That's why we're taking precautions."
Before the gulf war, the Army identified two strains of leishmaniasis as common to the region: leishmania tropica, which usually causes skin lesions that often heal on their own, and leishmania donovani, which causes a potentially life-threatening version accompanied by high fever, diarrhea, fatigue, enlargement of the liver or spleen and reduced blood cell counts.
In seven cases, soldiers did not develop the skin lesions seen in 15 other gulf-related outbreaks, but generally complained of high fever, mild anemia, stomach pain and diarrhea. Although these symptoms, along with evidence of bone marrow infection in all seven, pointed to something other than the mild form of the disease, the Army has ruled out the deadlier donovani strain in these cases, Colonel Oster said.
Army officials said the soldiers' symptoms, though serious, were not as severe as those caused by the classic, deadlier strain, which, Colonel Oster said, "is caused by a different organism."