MADISON, Wis. — Health officials say a dead crow found in Washington County has tested positive for West Nile virus.

It's the first bird to test positive for the virus in Wisconsin this year.

West Nile virus is spread to people through the bite of an infected mosquito. Mosquitoes become infected with the virus by feeding on infected birds, and then potentially transmit the virus by biting people.

Although few mosquitoes actually carry West Nile virus, health officials say infected birds serve as an early warning that the virus is present in the area and that people should take precautions against mosquito bites.

Last year, 57 cases of West Nile virus infection were reported among Wisconsin residents. That's the highest annual number of reported cases since surveillance of the disease began in Wisconsin.