West Nile Found in Fairfax

West Nile Found in Fairfax

An increase in infected mosquitoes has health officials bracing for more human cases this year.

The Fairfax County Health Department is detecting more cases of the West Nile virus in mosquitoes this year than last, making the first confirmed human case of the virus no surprise to health officials.

A 61-year-old City of Fairfax man contracted the virus sometime in August, and the state’s Division of Consolidated Laboratory Services in Richmond confirmed the positive results on Aug. 31.

Under the Fairfax County West Nile Surveillance Program, traps are spread throughout the county to test for the viral disease in mosquitoes. This year, test results from those traps have shown more mosquitoes are carrying West Nile than in 2004 and 2005, said Dr. Jorge Arias, supervisor for the county’s Disease Carrying Insects Program.

“If the infection rate [in mosquitoes] guides the number of human cases, then we would expect to see an increase from last year,” said Arias. “The odds are that people can get it.”

The increase has already occurred, since there were no human West Nile cases reported last year in Fairfax County. In 2002, 13 human cases were reported, including one fatality. Three reported human cases followed in 2003, and the only reported case in 2004 resulted in death.

The number of cases in the state might be understated, however, for several reasons.

“Our state criteria is that all samples must be tested by our state lab to be confirmed as West Nile,” said David Gaines, a state public health entomologist. “It requires a trained person to interpret the results.”

Gaines said many doctors use private labs, therefore some cases “slip through the cracks” since the labs don’t always send samples to the state for official testing. This doesn’t happen too often though, said Gaines, and other factors contribute to unreported cases of the virus.

“A lot of times patients don’t want to be stuck with a needle again, so they’re not going to submit to a blood test so the state can confirm a case or not,” said Gaines.

The state tests look for human antibody responses to West Nile, which indicate its presence in the body. These antibodies are measured in blood or cerebrospinal fluid, the fluid surrounding the brain and spinal cord, and can usually be detected within eight days of the onset of symptoms, according to data from the Centers for Disease Control and Prevention.

The virus is not always detected though, said Lucy Caldwell, spokesperson for the Virginia Department of Health. Many people contract the disease without knowing it, because symptoms vary from person to person.

Common symptoms are similar to those of the flu, such as fever and fatigue, but the health department reports that 80 percent of people infected with the virus show no symptoms at all, thus lack a reason to ask their doctors to test for the virus. Arias said it is up to individuals to take preventative steps against contracting West Nile.

“There are no vaccines and no anti-viral drug that will kill the West Nile virus,” said Arias. “One of the most important things is personal protection.”

In addition to wearing insect repellant and avoiding the outdoors when mosquitoes are biting, people should wear long, loose fitting and light-colored clothing, said Arias. Also, he said reducing breeding opportunities for mosquitoes provides a safer home environment. Mosquitoes lay eggs where water has collected, so taking the time to eliminate these areas can dramatically reduce the number of mosquitoes living in the neighborhood, said Arias.

Another personal responsibility is alerting doctors of West Nile suspicions, said Caldwell. While she said many people can fight off the virus naturally because of antibodies, there is always the chance that the virus can become serious.

“It’s up to people to let their doctors know they’ve been bitten by mosquitoes [if symptoms occur],” said Caldwell.