By Barbara Burnham and Amy T. Silva
WASHINGTON – Maryland officials said Thursday that two crows infected with the West Nile virus were discovered in Baltimore and Howard counties last week, the first two cases of the virus confirmed in the state this year.
The birds – one discovered in Relay and the other in Columbia – are only the second and third to be found in Maryland with the disease. One bird with West Nile virus was found Oct. 14 in Baltimore City.
While state officials said the latest discovery posed no immediate health risk, they urged state residents to take appropriate precautions against the mosquitoes that spread the virus between birds and humans.
Officials said “the best precaution against the West Nile virus is prevention” and urged people to eliminate areas where mosquitoes collect, such as pools of water found in flower pots, wading pools and clogged rain gutters. Mosquitoes can thrive and breed in as little as one-half inch of pooled water.
People should also wear long-sleeve shirts, long pants and a hat when outside, use mosquito repellents and avoid outdoor activities at dawn and dusk, peak times for mosquitoes.
Maryland health officials began stepped-up monitoring earlier this week of dead birds found in the area, as birds began their annual migration south. That, and increased awareness by residents, could have contributed to the latest discovery, said Dr. Jeff Roche of the Maryland Department of Health and Mental Hygiene.
“By this time last year, we had tested only a handful,” of birds, said Roche. Officials have tested hundreds of birds this year so far.
Roche said not all crows migrate, so it’s hard to say if either of the two crows were infected here or elsewhere.
Maryland officials said they have yet to find a mosquito infected with the West Nile virus in the state. All summer, federal and state officials have been checking mosquitoes that were caught within a few miles of the area where the two infected crows were later discovered, said Cyrus Lesser of the Maryland Department of Agriculture.
“If it was widespread, we would have indication from our surveillance,” said Lesser.
Monitoring efforts will continue through November, said Roche. The first good, hard frost should kill the adult mosquitoes for this season.
The state Agriculture Department also said it will spray insecticide after dark Friday in Howard and Baltimore counties. Officials said the insecticide is not harmful to people or pets, but they recommended anyone uncomfortable with the spraying should remain indoors or leave the area while treatment occurs.
Only one of the two birds was found dead, while one was found sick by county residents who reported it to the health department, Roche said. It lived for only a short time.
People infected with the West Nile virus may have symptoms similar to encephalitis, including fever, stiff neck, disorientation and paralysis. People should contact their doctor immediately if they develop any West Nile virus symptoms.