Maryland Health Officials Confirm First Case of West Nile Virus

Aedes triseriatus mosquito
PHOTO | CDC/ Robert S. Craig

The Maryland Department of Health (MDH) today confirmed the first case of a person with West Nile virus (WNV) in Maryland this year.

The infected individual is an adult living in the National Capital Region in Maryland. The Health Department routinely tracks and responds to mosquito-borne infections; no other locally acquired insect-borne infections have been identified this year in the state.

The number of human West Nile virus cases in Maryland has varied greatly from year to year. In 2003, there were 73 cases. In 2012, there were 47 cases; in 2015, 46 cases; and in 2018, 45 cases.

There are simple ways to reduce the risk of getting infected. They include:

• Avoiding areas of high mosquito activity.
• Wearing long pants, long-sleeved shirts and hats when outdoors.
• Using an EPA-registered insect repellent according to package directions.

Four out of five individuals infected with the virus will not have any symptoms. People who do develop illness usually will have any combination of fever, headache, body aches, skin rash vomiting, or diarrhea. These symptoms generally appear 2 to 14 days following the bite of an infected mosquito. Fewer than 1 percent of people 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.

People 60 years of age and older have the greatest risk of developing severe disease. People with compromised immune systems also may be at high risk of infection. In rare instances, the infection can be fatal.

Officials urge residents to monitor their 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.
• Empty or screen corrugated drain pipes.
• 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 the 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 West Nile virus 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://dnr.maryland.gov/Wildlife/Pages/plants_wildlife/wildlifeproblems.aspx. Detailed instructions on what to do when you find a sick or dead bird can be found at https://phpa.health.maryland.gov/OIDEOR/CZVBD/Pages/west-nile-virus.aspx.

Additional information on West Nile virus is available on the Maryland Department of Health website, the Maryland Department of Agriculture website, and the U.S. Centers for Disease Control and Prevention website.

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