First West Nile Virus-Positive Mosquito Pool in 2010 Confirmed

Simple Actions Can Reduce Risk

ANNAPOLIS, MD (July 22, 2010) – The Maryland Department of Agriculture (MDA) announces the first detection of a West Nile virus (WNV) mosquito pool in Maryland in 2010.  On Monday, the Maryland Department of Health and Mental Hygiene (DHMH) confirmed the presence of WNV in mosquitoes collected by Maryland Department of Agriculture personnel on July 13 in the Linthicum area of Anne Arundel County. This community participates in the cooperative mosquito control program and a routine spraying occurred on July 20 with a subsequent spraying scheduled for next Tuesday, July 27. MDA mosquito control personnel continue to work aggressively to reduce mosquito populations across the State.

“We know that West Nile virus may be present throughout Maryland. It typically appears at this time in the summer, so we are not surprised with this positive finding,” says Secretary of Agriculture Buddy Hance. “The confirmation of virus-positive mosquitoes serves as a reminder to all residents to continue protecting themselves against mosquito bites and to conduct backyard mosquito control activities in addition to MDA’s routine surveillance and spray activities.”
The MDA mosquito control office, in cooperation with DHMH, is conducting state-wide surveillance activities to monitor mosquito populations and detect mosquito-borne viruses of public health concern. Surveillance activities for adult mosquitoes use traps and landing rate counts.  Mosquito control activities conducted by MDA include larviciding and spray programs for adult mosquitoes in communities that voluntarily participate in the agency’s program. Additional mosquito-borne disease surveillance is conducted by the U.S. Department of Defense on military installations in Maryland.

“Mosquito control remains especially important to decreasing the risk of infection with all mosquito borne diseases,” said Michael Cantwell, MDA chief of mosquito control.  “MDA is taking appropriate steps for mosquito surveillance and mosquito control activities in participating Maryland jurisdictions through the end of September.”

Most mosquitoes do not pose a threat to public health because they are not infected with viruses or other pathogens. Approximately 20 percent of people infected with WNV will develop West Nile fever, which is typically characterized by fever, headache, and body aches and which can last for just a few days or as long as several weeks. Less than one percent of people bitten by a mosquito carrying West Nile virus will develop a more severe form of the disease.  People most at risk for developing severe disease are those over 50 and those with already compromised immune systems; however, all residents should continue to take measures to protect themselves from mosquito bites.  These measures include:

•    Avoid unnecessary outdoor activities at dawn and dusk when mosquitoes are most active;

•    Wear insect repellents, according to product labels, especially if you will be outside between the hours of dusk and dawn, when mosquitoes are most active.

•    Wear long sleeves and long pants to help avoid mosquito bites. Avoid mosquito infested areas. •    Install and inspect window and door screens in homes and stables and repair any holes found.

•    Remove standing water from flower pots, tarps, trash receptacles, and other containers; •    Vaccinate horses, mules, donkeys and ratites (flightless birds) according to your veterinarian’s advice.

•    Flush pet food and water bowls and bird baths regularly, and,

•    Remove unnecessary water-holding containers.

Currently there is no WNV vaccine for humans. There are, however, effective vaccines for horses, ostriches and emus – also known as ratites. Owners are encouraged to get their animals vaccinated and boostered in a timely manner in consultation with their veterinarian.

Dog owners are also urged to have their pets checked for heartworms, the most common disease transmitted by mosquitoes in Maryland. Dogs in all Maryland jurisdictions should be placed on a heartworm preventive program. Pet owners should consult with their veterinarians.

For more information about mosquito-borne diseases, contact your local health department. The following websites are available to provide additional information:

•    DHMH, www.dhmh.state.md.us or www.edcp.org/html/west_nile.cfm

•    Maryland Department of Agriculture, www.mda.state.md.us

•    Maryland Department of Natural Resources, www.dnr.state.md.us

•    Centers for Disease Control and Prevention, www.cdc.gov/westnile 

For additional information about MDA’s mosquito control program, please call 410-841-5870 or visit www.mda.state.md.us.

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