Mosquitoes have been spreading more than West Nile virus in some parts of the country lately — they've also been spreading a little hysteria.
Public health officials are assuring Americans that the blood supply is safe, as scientists at the Centers for Disease Control work to determine if a Georgia woman's donated organs may have infected four transplant recipients with the West Nile virus.
Questions remain over whether the woman contracted the virus from a mosquito bite or from one of the 37 units of blood she received before she died in August of injuries stemming from a car crash.
Concerns have arisen over the lack of a West Nile screening process in donated blood and organs. One report suggests the possibility that blood donors might be asked about whether they have recently been bitten by a mosquito.
Dr. Kirsten Alcorn, director of transfusion services at the Washington Hospital Center in Washington, D.C., believes this is an impractical solution.
"I think the rate of infection in humans is so low, with such a minimal illness in most individuals, that it would be nearly impossible to accurately screen donors on anything other than them feeling well and not being in an immediate period after not having felt well," she says. "Most blood centers do defer donors temporarily after even minor illnesses."
Dr. John Fung, chief of transplant surgery at the University of Pittsburgh, agrees, and says a mosquito bite-screening process would probably be detrimental to the blood supply.
"I believe that denying blood donation for a period of two-three weeks after a mosquito bite may be an overreaction and lead to exacerbation of an already critically low blood supply," he says.
"The way to assure that the blood supply is safe is to enhance donation, to improve screening methods and in the case of West Nile virus, to go after the source and reduce the mosquito population," he says.
"No one can promise that there won't be transmission of something. This is the current situation, even with very reliable hepatitis- and HIV-screening tools," he adds.
Cases Surpass Last Year’s Outbreak
Outbreaks of the potentially fatal virus have been on the rise this year. So far, with several months to go during which the disease can be transmitted, there have been 371 human cases and 16 deaths, says Dawn Wesson, associate professor of tropical medicine at the Tulane School of Public Health and Tropical Medicine in New Orleans.
By contrast, there were just 149 cases and 18 deaths altogether from 1999 to 2001, says Wesson, adding: "So this year we have already surpassed the case total of the first three years combined. We could exceed 500 cases this year."
Does Your State Have West Nile Virus?
Correspondingly, some doctors in the South and Midwest report an increase in the number of calls from concerned patients, especially in states hit hardest by the disease and with the densest mosquito populations.
"It has created serious concern among the folks here, and we have received many calls and had several visits from patients," says Dr. Michael Flemming, a general care practitioner in Shreveport, La.
DEET Can Be Dangerous
Doctors in Minneapolis say they've also being inundated with calls from parents worried about the disease. But the trend seems to also be coinciding with another worrying development — decreasing supply of insect repellent in area stores.