Faced with a concentration of mosquitoes that have tested positive for the West Nile virus in the southeastern part of Baltimore County, the state agriculture department announced yesterday that it would begin weekly nighttime spraying immediately in Rosedale and Garden Village.
This is the first time this year the state has initiated spraying mosquitoes in a community specifically because of West Nile virus. About 2,000 communities across Maryland participate in the Maryland Department of Agriculture's routine mosquito control program, which includes regular surveillance, larvae control and adult mosquito spraying.
The neighborhoods to be sprayed -- an area of about 1,700 acres -- are bordered by Hazelwood Avenue-Golden Ring Road, U.S. 40 and the Baltimore City line. These areas do not participate in the state's routine mosquito control program.
Gary Adams, a Hillbrook-Camelot resident who belongs to the Greater Rosedale Community Council, said the residents he has spoken with are pleased with the state's decision to spray their neighborhood for mosquitoes.
"If you do any walking at nighttime you get attacked by mosquitoes," said Adams, who walks five to six miles in the evening.
The area, which is heavily populated by families and seniors, has several streams, many of which have been reduced to "stagnant pools of water" this summer because of lack of rain, Adams said. Reports in the national press about the West Nile virus have raised concern in the community, he added.
The first spraying will occur between midnight and 5 a.m. tomorrow. Sprayings will likely take place on subsequent Wednesdays at the same time through next month, weather permitting.
The state Health Department said West Nile virus has been commonly found in humans, birds and other animals in Africa, Eastern Europe and the Middle East. Until 1999, it had not been detected in the United States.
The virus spreads when mosquitoes feed on West Nile-infected birds. This year, state officials have confirmed the virus in 172 birds and in 17 pools of mosquitoes in the state.
Last week, health authorities reported that an 80-year-old Baltimore man was Maryland's first probable case of West Nile virus infection this year. Last year, six Marylanders had serious West Nile infections, and three died.
For the spraying, crews use a solution of mineral oil mixed with a pesticide called permethrin in a volume of less than 1 fluid ounce an acre, said Cyrus Lesser, chief of the mosquito control section of the Department of Agriculture.
Trucks spray the solution in a light mist 20 feet into the air, and the mist drifts downwind about 300 feet. "It should kill about 90 percent of the mosquitoes it comes in contact with," Lesser said.
The pesticides that will be used are registered with the Environmental Protection Agency and are considered safe to humans when used according to labeling, said the county Health Department. However, for extra safety, the department said, these precautions should be taken during the hours of the spraying and for at least 30 minutes afterward:
Stay indoors and close windows and doors.
Turn off fans, window air conditioners and any air handling systems that pull outdoor air inside. Home central air conditioning systems do not need to be turned off.
Remove toys, furniture and clothes from outdoor areas or wash them before use.
Bring pets indoors and cover ornamental fishponds.
To assist in the reduction of disease-carrying mosquitoes, health and agriculture officials also recommend eliminating standing water from around homes, wearing long sleeves, long pants and mosquito repellent outdoors, and avoiding outdoor activities at dawn and dusk to avoid being bitten.