Maine reported its first confirmed case of a potentially serious disease – the mosquito-borne West Nile virus – on Wednesday.

The U.S. Centers for Disease Control and Prevention reported that an adult resident of Cumberland County had contracted the disease. The individual, whose name and gender are not being revealed, had to be hospitalized, the Maine Center for Disease Control and Prevention said in a news release.

This is the first case in a Maine resident since 2018. West Nile virus is a potentially serious disease caused by the bite of an infected mosquito, which can transmit the virus to humans, birds, horses, and some other mammals, according to the Maine CDC.

Maine has not detected West Nile virus in its samplings of mosquitoes this year, but New Hampshire and Massachusetts have reported positive activity in mosquitoes during the summer and fall.

The Maine CDC is urging residents and visitors to avoid being bitten by mosquitoes and to remain vigilant throughout the rest of the season. Mosquitoes remain active when the temperature is above 50 degrees and until the second heavy frost. Mosquitoes are most active at dusk and dawn.

The Maine CDC tests mosquitoes for West Nile virus throughout the summer months, starting in July.