Sorry, you need to enable JavaScript to visit this website.


DC Health

DC Agency Top Menu

-A +A
Bookmark and Share

DC Department of Health Identifies West Nile Virus in Mosquitoes for the First Time This Summer

Tuesday, July 26, 2011
Residents are advised to take caution, eliminate standing water and use bug repellent.

The District of Columbia Department of Health (DOH) announced today that it has positively identified the West Nile Virus in mosquito samples in the District. Residents should take caution as mosquitoes have the potential to transmit West Nile Virus (WNV) to humans, and it is important for residents to take the necessary steps to avoid contracting the virus.

West Nile Virus is mainly an infection of birds, but on occasions an infected mosquito may spread it to humans. The WNV is not transmitted directly from birds to humans and the risk of WNV infection is low. In human infections, the virus generally causes no symptoms, or may cause mild flu-like symptoms.

Senior citizens and those with suppressed immune symptoms are more vulnerable to infection. These residents are encouraged to stay indoors when mosquitoes are active. People with a higher risk of infection should wear long-sleeved shirts, long pants, and apply insect repellent with DEET or other mosquito repellents to exposed skin according to manufacturer’s directions. For children, use a product with DEET concentration of less than 30%.

DOH conducts seasonal testing for WNV throughout the city, and in response to positive test results, DOH staff will go to the infected site, advise residents regarding the elimination of any standing water, and apply larvicide to surrounding catch basins, sewer drains and stagnant pools to aid in mosquito control. The application of larvicide is intended to target and destroy mosquito larva before they can develop into adult mosquitoes. In addition, DOH staff will also distribute literature in and around the affected locations and areas. DOH will continue efforts to conduct surveillance and to control the mosquito population.

The majority of mosquito prevention begins with the resident. Residents should follow the below tips in order to assist in the eradication of mosquitoes in and around their neighborhoods.

Tips Residents Can Use to Reduce Mosquitoes in Their Area:

  1. Dispose of cans, bottles and open containers properly.  Store items for recycling in covered containers.
  2. Remove discarded tires. Drill drainage holes in tires used on playground equipment.
  3. Clean roof gutters and downspouts regularly.  Eliminate standing water from flat roofs.
  4. Turn over plastic wading pools, wheelbarrows, and canoes when not in use.
  5. Cover waste containers with tight-fitting lids; never allow lids or cans to accumulate water.
  6. Flush bird baths and potted plant trays twice each week.
  7. Adjust tarps over grills, firewood piles, boats or swimming pools to eliminate small pockets of water from standing several days.
  8. Re-grade low areas where water stands; clean debris in ditches to eliminate standing water in low spots.
  9. Maintain swimming pools, clean and chlorinate them as needed, aerate garden ponds and treat with “mosquito dunks” found at hardware stores.
  10. Fix dripping water faucets outside and eliminate puddles from air conditioners.
  11. Store pet food and water bowls inside when not in use.

For more information about this topic, please visit;, or call the WNV Call Center at (202) 535-2323.