MDA’s Mosquito Control Experiences Busy Start to the Season

ANNAPOLIS, MD (June 23, 2011) – Mosquito season has just begun but the Maryland Department of Agriculture’s Mosquito Control Program has already sprayed 88 percent of what it normally sprays by air in an average year – mostly on the Lower Eastern Shore.

“July 1 marks the 55th year of mosquito control services in Maryland. This season started out busier than most and the recent rains are expected to bring large numbers of mosquitoes,” said Agriculture Secretary Buddy Hance. “Over the years, the program has provided professional, effective mosquito reduction services to communities statewide. We remind residents that the single most effective way to reduce the risk of mosquito bites and mosquito-borne disease is to reduce the amount of standing water in the community.”

MDA is responsible for surveying and monitoring mosquito populations and implementing appropriate control activities, such as applying insecticide by air and ground, in order to prevent the occurrence of mosquito-borne diseases in humans, pets and livestock. Currently, MDA works with more than 2,000 communities in 16 counties that share the cost of mosquito control.

During the past 20 years, MDA has sprayed by air, on average, 159,000 acres a year to control adult mosquitoes. Since April, 140,000 acres have already been treated.

“It has been a busy start to our season,” said Mike Cantwell, chief of MDA’s Mosquito Control Program. “We have had early broods of salt marsh mosquitoes on the Eastern Shore in higher numbers than we expected this early in the spring. We have people monitoring the Chesapeake Bay and the Coastal Bay marshes. At the right time, we get the spray plane out there.”

The good news is that insecticide applications have proven to be effective and even affordable in keeping the mosquito populations manageable. An ounce sprayed from an airplane can disperse into droplets and treat an entire acre of adult mosquitoes for $1.40 an acre.

How much spraying needs to be done is often determined by the whims of weather. The wetter it is, the higher the risk, the busier the MDA staff. In 2009, MDA sprayed a total of 3 million acres during one of its more active years in recent history. The next year (2010), MDA sprayed 1 million acres during one of its slower years. This year, community ground larviciding and spray programs for adult mosquitoes is a little behind the average but on track to be an average year.

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, lose fitting, light colored clothing.
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.
Regularly clean bird baths and bowls for pet food and water, and,
Remove unnecessary water-holding containers.
There are several diseases that mosquitoes can transmit, not just West Nile virus (WNV). These include heartworm disease in dogs and several viruses that cause encephalitis in horses. 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, a 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.maryland.gov or http://ideha.dhmh.maryland.gov/CZVBD/west-nile.aspx
Maryland Department of Agriculture
Maryland Department of Natural Resources
Centers for Disease Control and Prevention
For additional information about MDA’s mosquito control program, please call 410-841-5870 or visit www.mda.state.md.us.