Health officials announced that a 40-something male resident of Middlesex County is the first human case of West Nile virus (WNV) in Massachusetts this year. He is currently hospitalized for his illness.

West Nile virus
Culex quinquefasciatus

The Massachusetts Department of Public Health (DPH) is conducting an epidemiological investigation to determine where the man was most likely exposed to infected mosquitoes. Assessment of WNV risk areas will depend on the findings of this investigation.

“Massachusetts is in peak season for possible West Nile virus infection for human infections,” said DPH State Public Health Veterinarian Dr. Catherine Brown.“We need to continue to take steps to protect ourselves against mosquito bites: use insect repellant, cover up, and reduce outdoor activities at dusk and after nightfall when mosquitoes are at their most active.”

In 2014, there were six human cases of WNV infection identified in Massachusetts. WNV is usually transmitted to humans through the bite of an infected mosquito. 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.