West Nile virus has been detected in mosquitoes in Boston for the first time this year, the Boston Public Health Commission announced Friday. The presence of WNV was confirmed Friday by the Massachusetts State Public Health Laboratory in a mosquito sample collected on July 14 in Jamaica Plain. No human or animal cases of WNV or Eastern Equine Encephalitis have been detected so far this year in the city. 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.West Nile Virus 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 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. When present, WNV symptoms tend to include fever and flu-like illness. In rare cases, more severe illness can occur. The most effective way to avoid WNV is to take measures to prevent mosquito bites. 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. 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.