Source(s):
Walter Tabachnick wjt@mail.ifas.ufl.edu, 772-778-7200 ext. 124

View Photo

VERO BEACH, Fla.—As Florida hits its peak period for mosquito-borne diseases, the state is seeing an increased number of infected sentinel chickens and horses, and University of Florida medical entomologists are warning Floridians to take precautions.

The number of birds and horses infected with West Nile virus and eastern equine encephalitis, or EEE, is greater than last year at this time, and the number of horses with EEE has more than tripled this year, reaching epidemic levels in North Florida, UF scientists and state officials say.

Scientists at UF’s Florida Medical Entomology Laboratory in Vero Beach are warning that Floridians need to be vigilant in protecting themselves and their animals from mosquito bites.

“Residents need to be reminded that there is risk for contracting mosquito-borne diseases and that the risk for contracting these diseases in Florida this year is likely similar to last year if not greater, when there were 28 confirmed human cases of West Nile in the state,” said Walter Tabachnick, director of the Vero Beach laboratory. The lab is part of UF’s Institute of Food and Agricultural Sciences.

At this time last year, 20 states in the nation reported birds and horses that carried mosquito-borne West Nile virus, according to the U.S. Centers for Disease Control and Prevention in Atlanta. This year, 32 states already have reported infected animals. In Florida, 29 of 67 counties have reported the virus this year, compared to 18 at this time last year, according to the Florida Department of Health.

West Nile infected nearly 4,200 Americans in 2002, taking 284 lives. This year, four have died from the virus, and a man in Brunswick, Ga., died from EEE.

The encephalitis virus is more deadly to people than West Nile; however, human cases of eastern equine encephalitis are infrequent, Tabachnick said.

Among people, 80 percent who become infected with West Nile will develop no symptoms and less than 1 percent will die from it, while 30 percent of EEE victims will die from the virus. In Florida, 46 counties have reported EEE virus activity, compared to 16 at this time last year.

West Nile and EEE viruses have claimed fewer lives to date this year than last year, but the number of Florida horses infected with EEE has tripled this year, compared to last year’s totals at this time. So far this year, 158 horses in 42 of Florida’s counties have been diagnosed with the virus compared to 25 cases the same time last year. Many of the infected horses have died.

Charles Bronson, commissioner of the Florida Department of Agriculture and Consumer Services, is also urging horse owners to protect their animals by having them vaccinated, which can save the animals’ lives.

A vaccine to protect people against West Nile currently is not available; however, the CDC is scheduled to test one at the end of the summer. The vaccine is similar to that used to protect humans against another mosquito-borne disease called Yellow Fever.

“At present, the only defense humans have against mosquitoes and pathogens like West Nile and eastern equine encephalitis viruses is to prevent mosquito bites,” Tabachnick said. “Thankfully many regions of Florida have very effective, efficient and environmentally proper mosquito control organizations to help reduce the numbers of biting mosquitoes,” he said.

Tabachnick said residents should take the following precautions to protect themselves and their families, particularly during periods and in regions with intense mosquito activity:

• Avoid outdoor activity at dawn and dusk.
• Wear slacks and long sleeves when outside.
• Use a mosquito repellant that contains DEET (N,N-diethyl-metatoluamide). Repellants with 10 percent DEET may last up to 3 hours, and those with 60 percent DEET may last up to 6-8 hours.
• Eliminate areas in yards that hold standing water.

Floridians also may help health officials by reporting dead birds that may hold valuable information about the diseases, Tabachnick said.

“We’re looking for birds that have died within the last 10 to 12 hours and seem to have suffered a nervous disorder,” said Charles Vogt, an environmental specialist at the Indian River County Department of Health. Residents should call the health department in their area to report recently killed birds, Vogt said.

Tabachnick and other scientists at the UF entomology lab conduct research to learn more about mosquito-borne diseases in order to better understand and control mosquito populations. Their work includes yearlong studies to determine which mosquitoes carry viruses that cause diseases, how the viruses are transmitted to humans and how the viruses are maintained in nature. The faculty pursues research on wastewater and storm-water mosquitoes, encephalitis biology and epidemiology, the biological control of mosquitoes, and the ecology, behavior and general biology of Florida mosquitoes.

“The most important work we do at the Florida Medical Entomology Laboratory is to provide knowledge that will be useful to improve human health and well-being,” Tabachnick said.

“Mosquitoes, affected birds, weather conditions and a host of other variables are different in different regions of the U.S., and this has an impact on the biology of these complex diseases. It is essential that Florida have a research program that addresses Florida’s ecology.

“We know that the ecologies, the mosquitoes that are involved differ in New York, for example, than they are in South Florida. A major goal is to determine differences that occur within Florida,” he said.

-30-

0