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DHMH Press Releases : West Nile Virus Surveillance Begins

West Nile Virus Surveillance Begins
Officials Urge Marylanders to Take Precautions
BALTIMORE (July 17, 2014) – The Maryland Department of Health and Mental Hygiene has begun tracking West Nile virus (WNV) and other diseases transmitted by mosquitoes for the 2014 season. Maryland residents should take precautions to protect themselves and their families from mosquito bites in order to prevent West Nile Virus. The Department also tracks cases of imported mosquito-borne diseases, such as chikungunya and dengue viruses.

“We expect to see West Nile virus cases each year because it is established in Maryland, but we are also looking for imported mosquito-borne diseases in Maryland residents,” said Dr. Katherine Feldman, State Public Health Veterinarian at DHMH. “Maryland residents returning from a visit in the Caribbean who experience fever should seek medical care and make their provider aware of their recent travel.”

The symptoms of chikungunya infection resemble those of dengue, another serious mosquito-borne infection that is common throughout the Caribbean islands and can be imported into Maryland. Travelers who experience fever, joint pains, and other symptoms such as headache, muscle pains, or rash should seek medical care. Health care providers should be on the alert for possible cases.

Most individuals infected with WNV will not have any symptoms. People who do develop illness will usually have any combination of fever, headache, body aches, skin rash and swollen lymph glands. These symptoms generally appear three 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 severe disease. People who are immunocompromised may also be at higher risk of WNV infection.

In addition, the Asian Tiger Mosquito, an invasive pest from Asia, has become more of a problem in the last few years and behaves differently from native mosquitoes. Tigers are more aggressive, will follow people into their homes and come out during the day. They primarily breed in small, man-made containers, especially those on the ground in shady, damp areas. Native mosquitoes tend to breed in wetlands and marshes. The Maryland Department of Agriculture (MDA) posted a new Web page this season dedicated to helping residents identify what kind of mosquitoes they have and providing tips for reducing breeding grounds for Tiger Mosquitoes. See:

  Other 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.
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:
  • Replace corrugated drain pipe off of downspouts with smooth PVC piping.Each trough in the corrugated pipe is a potential breeding ground.
  • 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.
For additional information on West Nile virus, visit:

For additional information on chikungunya virus, visit:
For additional information on dengue virus, visit:
To watch a video from MDA, Don’t Get Bitten: Avoid Breeding Mosquitoes in Your Backyard,” visit: