In a follow-up on the West Nile virus (WNV) infection situation in Massachusetts,  state health officials report four more human cases of WNV in the state this year, bringing the total to 9.

Massachusetts/National Atlas
Massachusetts/National Atlas

The newest cases include a man in his 40s from Middlesex County who is hospitalized due to his illness; a man in his 60s from Bristol County who is hospitalized due to his illness; a woman in her 20s from Essex County who was hospitalized during her illness and a woman in her 80s from Suffolk County who was hospitalized during her illness.

In 2017, there were 6 human cases of WNV infection identified in Massachusetts.

In addition, a horse from Hampshire County and a llama from Worcester County have also been diagnosed with WNV this year.

“The risk for additional people to get infected with WNV is ongoing,” said Public Health Commissioner Monica Bharel, MD, MPH. “It is extremely important for people to take steps to avoid mosquito bites including using repellents, wearing clothing to reduce exposed skin, dumping standing water, and moving indoors when mosquitoes are present.”

“Even though Labor Day is the unofficial last day of summer in many people’s minds, September is still a month when we typically see many of our human cases of WNV,” said DPH State Epidemiologist Dr. Catherine Brown. “Today’s announcement illustrates why we continue to urge everyone to be vigilant about avoiding mosquito bites.”

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.