Wisconsin public health officials are reporting the first mosquitoes of the year to test positive for the West Nile virus.
State and city health officials announced Thursday that three mosquito pools in Milwaukee tested positive for West Nile last month.
The officials are urging people to protect themselves against mosquito bites - especially over the Labor Day holiday weekend.
Historically, they say, human cases tend to occur in late summer and early fall in Wisconsin and surrounding states.
Symptoms include fever, headache and a rash that lasts a few days. Most people will have mild or no symptoms, but some may develop serious complications.
The Milwaukee Journal Sentinel notes that Wisconsin reported its first human infections in 2002 with 52 human cases. The state had only one confirmed human case last year. (Copyright 2010 by The Associated Press. All Rights Reserved.)