Season’s first West Nile virus-positive mosquito sample in Massachusetts
The presence of WNV was confirmed by the Massachusetts State Public Health Laboratory in a mosquito sample that was collected July 3 in the city of Boston in Suffolk County.
No human or animal cases of WNV or Eastern Equine Encephalitis (EEE) have been detected so far this year.
There is no elevated risk level or risk-level change associated with this finding.
“The first WNV positive mosquito sample is often identified in Massachusetts sometime during the last week of June or the first week in July,” said DPH State Epidemiologist Dr. Catherine Brown.
“Risk for human infection generally builds through the season with peak risk occurring in August.”
WNV is usually transmitted to humans through the bite of an infected mosquito.
In 2018, there were 49 human cases of WNV infection acquired in Massachusetts - the greatest number of cases the Commonwealth has ever had in a single year.
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. ■