A man in his 70s became the second person in Massachusetts to be infected with West Nile Virus this year, the State Department of Public Health said Friday.
The man, who was not identified, was exposed to the virus in Suffolk County, which was considered to be at moderate risk, the State Department of Public Health said in a statement. The incident prompted officials to increase its risk level for the virus in Boston, Brookline, Cambridge, and Somerville from moderate to high.
The risk of infection in the Greater Boston area is considered moderate to high, the statement said. There were 11 human cases of West Nile Virus in Massachusetts in 2021.
The virus “is usually transmitted to humans through the bite of an infected mosquito,” the statement said. “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.”
Symptoms can include fever and flu-like illness, the statement said. More severe illnesses can occur, but are rare.
Adam Sennott can be reached at adam.sennott@globe.com.