A dead crow found in Dedham last week is among 10 out of 60 dead birds tested this year that have been infected with West Nile virus, according to the state Department of Public Health.
Last year, one of two dead Dedham birds tested by the state was also carrying the virus.
Last week, the state also confirmed that a dead bird found in Needham was infected, Dedham Board of Health Director Catherine Cardinale said.
There have been no human infections in 2008, according to the state Department of Public Health. At least four people were infected with West Nile virus last year in Massachusetts.
Department spokeswoman Donna Rheaume said it isn't unusual for one town to have two infected animals within two years, but it does alert the state that there are likely infected mosquito populations within the town.
Rheaume offered the same advice that the Dedham Board of Health shared in an advisory Friday: Wear insect repellent, long sleeves and pants to avoid mosquito bites and drain any pools of water on your property.
"Particularly with the rain we've had recently, this creates natural standing pools of water so it's important that people take a look at their properties because those are a breeding ground for mosquitoes," she said.
"This is the time of the summer that we see them (mosquitoes) and this year in particular we noticed a higher population of mosquitoes that carry West Nile virus."
The Dedham Department of Public Works is treating catch basins to kill mosquito larvae, and the Norfolk County Mosquito Control will continue to spray each day and test the insects for the virus, Cardinale said.
Female mosquitoes, which use blood to make their eggs, are attracted to the carbon dioxide that humans and other animals exhale and are also drawn to lactic acid on the skin of their victims, according to the state.
They can follow a stream of carbon dioxide from up to 50 feet away.
Most mosquitoes don't carry West Nile virus, encephalitis or other viruses that make humans sick, and the risk of illness following a mosquito bite is small, according to the Boston Public Health Commission.
However, those who develop high fever, confusion, severe headache, stiff neck, or whose eyes become sensitive to light should see a doctor immediately, the commission advises.
Less than 1 percent of people infected will develop severe illness, including encephalitis or meningitis, the Department of Public Health says.
The symptoms of severe illness can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis. About 10 percent of people who develop severe illness from West Nile virus will die, according to the department.
Daily News staff writer Lindsey Parietti can be reached at lindsey.parietti@cnc.com.
