In August 2002, two Loudoun County teenagers were diagnosed with the same species of malaria, Plasmodium vivax, and responded well to treatment. The Health Department, working with the Virginia Department of Health and the Centers for Disease Control and Prevention (CDC), determined that they most likely contracted the malaria from the bite of an infected mosquito near their homes in the Cascades and Sugarland Run communities.
Investigation by the Health Department at that time found no infected mosquitoes in the suspected area, though significant numbers of mosquitoes that could transmit malaria, Anopheles quadrimaculatus, were caught in traps set up throughout these communities. A successful adult mosquito spraying campaign was then done in the affected area to reduce the chance that any further residents would contract the malaria parasite. The Health Department also conducted surveillance with local health care providers and emergency departments and found no additional ill residents at that time.
Most people infected with malaria will become sick in two to three weeks, but the onset may be delayed for up to eight to ten months.
Symptoms of malaria include fever and flu-like illness, including shaking chills, headache, muscle aches, and tiredness. Nausea, vomiting, and diarrhea may also occur. Malaria may also cause anemia and jaundice (yellow coloring of the skin and eyes).
On March 12, a teenager from the South Riding community of Loudoun County began having symptoms of malaria, according to Dr. David Goodfriend, director of the Loudoun County Health Department. She was started on medications and shortly afterwards began feeling much better.
Subsequent testing found that she had contracted the same malaria species as other two teens, Plasmodium vivax.
The Health Department has determined that this third teenager spent her summer in the same area as the two other infected teens and remembers receiving numerous mosquito bites at that time. She has not been back to that community since last year and does not recall being bitten by mosquitoes recently.
With the onset of spring, Clarke Mosquito, the company that performs mosquito surveillance for Loudoun County, had already resumed malaria surveillance. Results to date have found no evidence that any mosquitoes infected with malaria had survived the winter. This surveillance will continue until the county can be confident that no overwintering of infected mosquitoes has occurred.
The county will be conducting extensive surveillance and mosquito abatement efforts throughout the year to keep Loudoun residents safe from these infections. In addition, citizens can take simple steps that will significantly reduce their chances of being bitten by mosquitoes.
These include:
* Check window and door screens to ensure that mosquitoes don't enter the home.
* Wear long, loose and light-colored clothing.
* Use insect repellent products with no more than 35 percent DEET for adults and less than 10 percent for children. Follow instructions when using insect repellents.
* Turn over or remove containers in the yard where water collects, such as old tires, potted plant trays, buckets and toys.
* Eliminate standing water on tarps or flat roofs.
* Clean out birdbaths and wading pools once a week.
* Clean roof gutters and downspout screens regularly.