West Nile Virus Detected in Maryland Resident and Mosquitoes

BALTIMORE, MD (August 10, 2012) – The Maryland Department of Health and Mental Hygiene (DHMH) today announced that an adult in Central Maryland is the State’s first confirmed case of symptomatic West Nile virus (WNV) infection in 2012. West Nile virus was also detected in a pool of mosquitoes collected in Montgomery County by the U.S. Department of Defense. A mosquito pool is a group of mosquitoes collected at one of several trap sites across the State.

“West Nile Virus continues to threaten the health of Maryland residents," said DHMH Secretary Dr. Joshua M. Sharfstein. "These findings remind us that there are basic actions we can all take to reduce our risk of getting infected."

Measures people can take to protect themselves include:

Avoid areas of high mosquito activity
Avoid unnecessary outdoor activities at dawn and dusk when mosquitoes are most active
Wear long pants, long-sleeved shirts and hats when concerned about mosquito exposure
Use an EPA-registered insect repellent according to package directions

Most individuals infected with West Nile virus will not have any symptoms. People that do develop illness will usually have any combination of: fever, headache, body aches, skin rash and swollen lymph glands. These symptoms generally appear 3 to 15 days following the bite of an infected mosquito. Less than one percent of persons exposed to the virus will develop more severe infections with symptoms such as headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness and paralysis. In rare instances, WNV can be fatal. Persons over 50 years of age have the highest risk of developing more severe disease. People who are immunocompromised may also be at high risk of WNV infection.

The Centers for Disease and Control and Prevention recently released a media advisory announcing that some areas of the country have experienced greater numbers of WNV infections in humans, birds, and mosquitoes. Although Maryland is not among those states reporting increased WNV activity, the first confirmed human case in Maryland serves as an important reminder to Marylanders to take steps to prevent WNV infection.

The number of human WNV cases in Maryland has varied over the past several years. Seventy-three human WNV cases were reported in the peak year of 2003. Twenty-three cases were reported in 2010, and 19 human WNV cases were identified in 2011.

Residents are urged to monitor their own yards and gardens for standing water that can serve as a breeding ground for mosquitoes. Small amounts of water in a discarded can or container will support dozens of mosquitoes. To eliminate mosquito-breeding areas:

Clean rain gutters to allow water to flow freely
Remove old tires or drill drainage holes in tires used as playground equipment
Turn over wading pools, wheelbarrows, wagons and carts when not in use. Flush water from bottom of plant holders twice a week
Replace water in birdbaths at least twice a week
Turn garbage can lids upside down and make sure trash receptacles are empty of water
Fix dripping faucets
Aerate ornamental pools and water gardens or stock with fish and use a circulating filter system

Although birds are not routinely tested for WNV in Maryland, sick or injured birds can be reported to an appropriate local wildlife rehabilitator. Residents can call 1-877-463-6497 for a list of licensed rehabilitators or visit the Maryland Department of Natural Resources web site athttp://www.dnr.state.md.us/wildlife/rehab.asp . Detailed instructions on what to do when you find a sick or dead bird can be found at http://ideha.dhmh.maryland.gov/OIDEOR/CZVBD/SitePages/west-nile.aspx.