BY REX SPRINGSTON TIMES-DISPATCH STAFF WRITER Sep 28, 2002 In Loudoun County, where two teenagers recently fell ill to malaria, two batches of mosquitoes have tested positive for the parasite, health officials said yesterday.

"This is the first time in over 20 years that positive mosquitoes have been found in conjunction with a human case in the United States," said Dr. David Goodfriend, director of the Loudoun Health Department.

"The good news," Goodfriend said, "is we don't know of anyone else who has gotten sick." Health officials checked hospitals and clinics after the teens fell ill.

The mosquitoes, batches from two traps in northern Loudoun, probably picked up malaria from a visitor from a tropical country where the disease is common, Goodfriend said.

While people in Loudoun might run a slight chance of contracting malaria, "this isn't a crisis at all," he said.

The strain of malaria in Loudoun is not the most deadly, although it can kill elderly or sick people. More often, it causes flulike chills.

Loudoun health officials are talking with colleagues in neighboring localities to ensure they are aware of the possible presence of the disease, Goodfriend said.

Unlike the West Nile virus, which has spread across much of the United States in three years, "there is no way malaria would spread across Virginia," said David N. Gaines, a public-health entomologist with the Virginia Department of Health.

The mosquitoes themselves do not travel far, rarely more than a half-mile. And they need reservoirs of the disease - infected people - which are rarely found, Gaines said.

By contrast, West Nile is carried by birds, and many thousands of birds are getting the disease and spreading it as they travel.

On a scale of one to 10, Gaines said, the chance of someone in Loudoun getting malaria is "much less than one." And the most likely way for someone in Richmond, for example, to get malaria is for a visitor to bring it here from a tropical country.

The malaria-carrying mosquito, Anopheles quadrimaculatus, breeds in ponds and streams and is active at night, Gaines said. In Loudoun, officials are advising residents to wear long sleeves, fix the screens on their homes and wear mosquito repellent when they go outside, especially at night.

Two Sterling residents, a 15-year-old boy and a 19-year-old woman, came down with the disease last month. They received drug treatment "and are feeling much better," Goodfriend said.

Officials have applied larvicide, a chemical that kills baby mosquitoes, to waters in the area, and they have sprayed to kill adult mosquitoes.

About 1,200 cases of malaria are diagnosed nationwide annually, and Virginia confirms about 60 cases a year. But the illness is almost always found in people who have traveled outside the United States.

Neither of the Loudoun victims, however, had traveled outside the country, officials said.

The mosquitoes that tested positive for malaria will be tested again, for confirmation, at a state lab in Richmond.

-- Anonymous, September 28, 2002