CONCORD, N.H. — New Hampshire health officials have identified the first batch of mosquitoes to test positive for the West Nile virus this season.

The batch was found recently in Manchester.

“West Nile virus is transmitted to humans from the bite of an infected mosquito,” said Ben Chan, state epidemiologist. He said the best way to prevent it and other mosquito-transmitted infections is to use insect repellent, avoid being outdoors between dusk and dawn when mosquitoes are most active, and remove any standing water from around the home.

The virus was first identified in New Hampshire in August 2000. The most recent case was in an adult in 2017.

The risk for West Nile virus and the eastern equine encephalitis virus will continue to increase until there is a statewide mosquito killing hard frost.

Symptoms of West Nile virus can include flu-like illness including fever, muscle aches, headaches and fatigue.