Update: West Nile Virus in Maryland

BALTIMORE (September 12, 2012) – With just over half of the surveillance season for West Nile virus behind us, 25 cases have been detected in Maryland residents, including two fatalities. The cases have been found in 13 counties; all of the infected individuals have been adults.

“Since West Nile virus was first detected in Maryland, it has had an impact on every part of the state," said DHMH Secretary Dr. Joshua M. Sharfstein. "It’s important for all Marylanders to take basic actions to reduce the 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 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 at http://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.

From now until the end of the West Nile virus surveillance season on October 31, 2012, the Department will update case counts online each Wednesday by noon. In addition, the Department will include county-level data as part of its surveillance report. To view the surveillance report, visit: http://ideha.dhmh.maryland.gov/OIDEOR/CZVBD/SitePages/west-nile.aspx.

For additional information on West Nile virus, visit: