Tick disease poses threat to blood supply

By STEVE MITCHELL, UPI Medical Correspondent  |  July 29, 2002 at 2:00 AM
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A potentially fatal disease spread by ticks may be on the increase and government and public health officials are concerned it could be infiltrating the blood supply.

Babesiosis, a mild malaria-like illness, is transmitted by Ixodes scapularis, the black-legged tick, the same creature that carries Lyme disease. So far, babesiosis largely has been confined to Nantucket and Martha's Vineyard, Mass., and parts of Long Island, N.Y.

In recent years, however, the tiny black-legged ticks -- also called deer ticks -- that carry the disease appear to be expanding their range, Sam Telford, a researcher at Harvard University, in Cambridge, Mass., who focuses on tickborne diseases, told United Press International.

"We do believe it's probably spreading," Peter Krause of the Connecticut Children's Medical Center in Hartford and the University of Connecticut School of Medicine in Farmington, told UPI. Krause noted people have become infected with the disease in New Jersey and farther inland in Connecticut, indicating it is spreading westward in that state.

This raises concern on two levels. People who pick up the disease from a tick are at risk of death because the disease can be fatal in 5 percent of cases and there is a risk they could transmit the protozoan that causes the disease to others if they donate blood, Krause said.

More than 30 cases of people contracting the disease through blood transfusions have been documented but the total number of cases is likely much higher because the disease often goes unrecognized and unreported, he said. In most people, the disease causes fever and aches for about a week, but it can have severe consequences and some people may have to be placed on life support.

"This disease is definitely underestimated," Krause said. "There are more cases than we realize and it's increasing." He added many physicians are becoming more aware of the disease and more labs are starting to test for it, "so we're going to be seeing more cases just because of increased recognition. Scientists know the risk of transmitting babesiosis via blood transfusions is a problem ... and they are looking for ways to decrease the possibility of this."

Krause noted both the American Red Cross and the Centers for Disease Control and Prevention in Atlanta are involved in a study to determine the prevalence of the disease and the risk posed to the blood supply.

Barbara Herwaldt, a medical epidemiologist with the CDC, told UPI the threat of babesiosis getting into the blood supply is "of concern," but she declined to elaborate further on the study or how much of a risk contaminated blood poses to the general population.

The Red Cross did not respond to phone calls from UPI seeking comment. Other blood bank organizations also are worried about the threat of babesiosis.

"It is relatively high on our priority list for transfusion infections," said Louis Katz, vice president of medical affairs at the Mississippi Valley Regional Blood Center in Davenport, Iowa, and chair of the American Association of Blood Banks transfusion/transmitted diseases committee.

"The reason it is an issue in blood banking now is due to environmental and demographic changes over the past years and people are now living where ticks are," Katz said. This means babesiosis infections are increasing so it is more likely infected people will donate blood, he said.

Although there is no test for screening blood for babesiosis, the Food and Drug Administration does require blood centers to ask about the disease and bar people from donating if they report ever having the disease, an FDA spokesman told UPI. However, this may not catch everyone infected with the disease because often people will catch it but the symptoms are so minor they do not realize they are infected, Krause said.

The FDA spokesman stressed, "The benefit of receiving a blood transfusion far outweighs any theoretical risk associated with receiving that transfusion." But he said, "The FDA would be very interested in a blood screening test (for babesiosis) being brought forward for evaluation," adding the agency is attempting to develop such a test.

People at greatest risk of contracting babesiosis via blood transfusions are the elderly, patients whose spleens have been removed and those with weakened immune systems due to surgery, cancer or HIV/AIDS, Krause said. In these patients, babesiosis is more likely to cause serious health problems or death. The disease also could interfere with recovery from surgery.

Krause said children also are at risk of contracting the disease but they seem to be protected from the serious complications.

Scientists likely will continue to focus on babesiosis in the near future. Telford said "the disease will get a lot of interest" next month at an international conference on Lyme and other tickborne diseases in New York City. He also predicted it will continue to spread and become more of an issue with the public at large.

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