Three people and one horse were infected with West Nile virus in Massachusetts, state health officials announced Friday.
Two of three people who contracted West Nile virus had to be hospitalized, but have since been discharged. The horse, which fell seriously ill, had to be euthanized, Department of Public Health officials said.
The human cases were identified as a woman in her 70s from Worcester County, a woman in her 60s from Middlesex County and woman in her 50s from Boston. The horse had been stabled in Hampshire County.
The announcement of the first cases of West Nile virus this year came days after health officials raised the risk level to moderate for the entire state. There were a total of six human cases of West Nile infection in Massachusetts in 2017.
"There has been an increase in WNV-infected mosquitoes identified this year throughout the state, an indication that the risk is widespread and ongoing," Massachusetts Public Health Commissioner Monica Bharel said in a statement.
Officials say most people infected with West Nile virus won't present symptoms; however, when they do occur, they tend to manifest as fever and flu-like illness, with more serious illness presenting in rare cases.
Experts recommend people apply insect repellent when outside, be aware of peak mosquito hours and wear long sleeves, long pants and socks to keep mosquitoes away from skin.