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West Nile Virus (WNV) is a widespread concern that could result in serious illness. Experts believe WNV is established as a seasonal epidemic in North America that flares up in the summer and continues into the fall. WNV is a virus that can be transferred to humans from a mosquito bite and rarely from transfusions, transplants, and mother-to-child (during pregnancy and while nursing). WNV is not spread through casual contact or human interaction. Thus, the easiest way to prevent WNV is to prevent mosquito bites. To protect yourself from WNV: use an EPA-registered insect repellent; avoid the outdoors at dusk and dawn; wear long sleeves and pants if outside during these times; install good screens on doors and windows; and remove, empty, or treat all sources of standing water near and around your home.

Approximately 80% of all people who are infected with WNV show no symptoms at all. Up to 20% of people infected will present mild symptoms, which can include fever, headache, body aches, nausea, vomiting, occasionally swollen lymph nodes, and a rash on the chest, stomach and back. These symptoms can last anywhere from a few days to several weeks. Nationwide, approximately 150 people per year will present serious symptoms when infected with the virus. These symptoms can include disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis. These symptoms may last several weeks, and neurological effects may be permanent. Symptoms will typically be present within three to 14 days after the bite by an infected mosquito. There is no specific treatment for WNV. With mild symptoms, hospital treatment is not necessary and symptoms will pass on their own. However, if serious symptoms are present, treatment should be sought at a hospital where supportive treatment and nursing care can be provided. For more information, visit, or call CDC at 800-CDC-INFO (English or Spanish) or 888-232-6348 (TTY).

Each year NAVFAC Washington updates the plan for addressing mosquitoes throughout the region. The WNV has been of particular concern due to the increasing population throughout the District and surrounding areas. DoD has assembled a map of the confirmed locations of WNV in the DC metro area. Weekly surveillance at each installation monitors both the number of mosquitoes and the presence of disease-carrying mosquitoes. If the presence of WNV is detected, a pesticide (Bacillus thuringiensis israelensis or BTI), is applied at the detected location. BTI is a type of bacteria that produces a chemical that is only toxic to mosquito larvae. BTI is used, not only for its effectiveness at killing mosquitoes, but also for its negligible environmental impact. Therefore, BTI is very safe to use in populated areas.

In 2012, only two installations, Marine Barracks Washington and Joint Base Anacostia-Bolling (JBAB) - both in Washington D.C., had mosquitoes that tested positive for WNV. Once the test results were received, Navy Bureau of Medicine and Surgery (BUMED) was notified and treatment was scheduled. The treatment was completed with continued weekly monitoring to confirm the issue has been resolved.