Record number of West Nile cases reported in the Mass.

This is a record year for the West Nile virus in Massachusetts. So far, 42 cases have been confirmed, the highest number ever reported in this state in a single year. The previous record was 33 in 2012.

The state's Department of Public Health on Friday announced four new cases in humans, all of which became sick enough to require hospitalization: a woman in her fifties; two men in their 60s in Middlesex County; and a woman in her sixties from Plymouth County. A horse from Franklin County died of the disease.

West Nile is usually transmitted by the bite of an infected mosquito. This year, warm, wet weather has encouraged mosquito growth and their ability to spread the virus. In comparison, there were six human cases in 2017 and 16 in 2016.

"The mosquito season is coming to an end, but mosquitoes will stay active on hotter and wetter days," said Public Health Commissioner Monica Bharel in a statement. And, she warned, mosquitoes at this time of year are more likely to carry West Nile virus.

"Long sleeves and pants will help reduce stings, and a mosquito repellent may still be needed when it's hot and humid," Bharel said.

The risk of getting West Nile virus is listed as "moderate" for most states, meaning that an infection is likely or has already occurred. But for Boston and some cities in the north and west, including Newton, Cambridge, Medford and Lynn, the risk is high, which means that many people may be infected.

People over the age of 50 or with weakened immune systems are encouraged to stay at home from dusk to dawn if they live in high-risk areas.

Most people infected with West Nile have no symptoms, but about 20% suffer from fever, headache, body aches, nausea, vomiting and sometimes swollen lymph nodes or a rash on the skin. torso. Rarely, West Nile can cause serious illness.

For more information, visit the Arbovirus Surveillance Web page at www.mass.gov/dph/mosquito or call the DPH Epidemiology Program at 617-983-6800.

Felice J. Freyer can be contacted at [email protected]. Follow her on Twitter @felicejfreyer