The Boston Public Health Commission (BPHC) announced last week that West Nile Virus (WNV) has been detected in mosquitoes in Boston for the first time this year.
The presence of WNV was confirmed July 16 by the Massachusetts State Public Health Laboratory in a mosquito sample collected on July 14, 2020 in Jamaica Plain. No human or animal cases of WNV or Eastern Equine Encephalitis (EEE) have been detected so far this year in the City of Boston. Although there is no elevated risk level or risk-level change associated with this finding, BPHC advises residents to prevent mosquito bites and to mosquito-proof their homes.
“It is typical to find West Nile Virus in mosquitoes in Boston at this time of year,” said Dr. Sarimer Sanchez, Director of the Infectious Disease Bureau at the Boston Public Health Commission. “However, it is also that time of year when many of us will be spending time outdoors, enjoying summertime in New England. When you or your family are outside, it is important that you take steps to prevent mosquito bites. That includes using an approved mosquito repellent, draining standing water from your yard and repairing window screens to keep mosquitos out of your home.”
West Nile Virus (WNV) is a rare but serious disease most often spread to people by the bite of an infected mosquito. WNV has been detected in Boston mosquitoes during the summer and fall months (June – November) every year since 2000, but WNV in people is rare. In 2020 and 2019, there were no human cases of WNV infection diagnosed in Boston residents. In 2018, there were seven human cases of WNV infection diagnosed in Boston residents.
While WNV can infect people of all ages, people over the age of 50 are at higher risk for severe disease. Most people infected with WNV will have no symptoms. When present, WNV symptoms tend to include fever and flu-like illness. In rare cases, more severe illness can occur. There is no vaccine or specific antiviral treatments for West Nile Virus infection. The most effective way to avoid WNV is to take measures to prevent mosquito bites.
Mosquitoes in Boston are most active from dusk to dawn during the months of July to September, but mosquitoes can spread disease until the first hard frost (as late as November). The risk can be reduced by using insect repellent when outdoors, especially from dusk to dawn and, when possible, wearing long-sleeved shirts and pants. Residents should also make sure that their window and door screens are in good repair to prevent mosquitoes from getting inside. To help prevent mosquitoes from breeding, BPHC advises residents to empty standing water from flowerpots, gutters, buckets, pool covers, pet water dishes, discarded tires, and birdbaths on a regular basis.