For the first time this year a mosquito pool in East Boston has tested positive for West Nile Virus (WNV). Tests performed earlier this week confirmed a WNV-positive mosquito pool in the neighborhood even after the city conducted a targeted mosquito-spraying program last month in Orient Heights.
Despite the new findings, there have still been no recorded human cases of mosquito-borne illnesses in Boston this year.
The Boston Public Health Commission encourages people to take simple precautions to reduce the risk of mosquito bites. These steps include using insect repellant when outdoors, especially from dusk to dawn when mosquitoes are more likely to be biting and, when possible, wearing clothing that includes long sleeves and pants. People should also mosquito-proof their home by making sure that their window and door screens are in good repair to prevent mosquitoes from getting into the house.
To prevent mosquitoes from breeding, the Boston Public Health Commission advises people to turn over unused flower pots, buckets, wheelbarrows, and garbage cans; remove leaves and other debris that can clog gutters and trap water; dispose of or cover old tires; and cover swimming pools when not in use.
WNV is most commonly transmitted to humans by the bite of a mosquito infected with the virus, but it poses very low risk to most people. Following simple safety measures can further reduce the risk.
The City of Boston, in partnership with the Suffolk County Mosquito Control Project, has placed larvicide in catch basins and wetlands in Eastie, a process designed to reduce the mosquito population. Targeted, truck-mounted aerosol spraying has also been performed to help control the mosquito population in certain areas of Boston.
While WNV is most commonly transmitted to humans by the bite of a mosquito infected with the virus, it poses very low risk to humans.
About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.
Up to 20 percent of the people who become infected have symptoms such as fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks.
Approximately 80 percent of people (about 4 out of 5) who are infected with WNV will not show any symptoms at all.
People typically develop symptoms between 3 and 14 days after the infected mosquito bites them.