Most people infected with the virus do not develop any symptoms, but those who do can experience high fever, disorientation, coma, tremors, convulsions, vision loss, numbness, or paralysis, according to the US Centers for Disease Control and Prevention.

The risk for West Nile virus is now high in 47 municipalities across Suffolk, Middlesex, Essex, and Worcester counties, the state Department of Public Health said.

Across Barnstable, Berkshire, Bristol, Essex, Franklin, Hampden, Hampshire, Middlesex, Norfolk, Plymouth, Suffolk, and Worcester counties, 210 cities and towns face moderate risk.

“We are almost out of the peak season for the spread of West Nile virus‚” said Robbie Goldstein, the state’s public health commissioner. “But because some risk will continue until the first hard frost, we are encouraging everyone to continue to take the necessary steps to protect themselves from mosquito bites by using mosquito repellent and wearing long sleeves and pants to reduce exposed skin.”

The first West Nile-positive mosquitoes in Massachusetts were announced on June 17. There has also been one animal case of West Nile virus this year in a goat, according to the Department of Public Health.

This season, 445 samples from mosquitos have been detected.

Another mosquito-borne disease, Eastern equine encephalitis, also known as EEE, has been detected in Massachusetts this year. There have been 23 EEE-positive mosquito samples and no human or animal cases, according to the Department of Public Health.

Although only a few cases of EEE infecting humans are reported in the country each year, the disease can be severe, according to the CDC. Around 30 percent of people who develop severe cases die, and many survivors are left with ongoing neurological problems.

Public health officials urge residents to regularly check the Massachusetts Arbovirus Update page. It updates risk levels in communities around the state daily and provides updates on new cases of both West Nile virus and EEE.

Sabrina Lam can be reached at sabrina.lam@globe.com.