First Mosquito Pools Test Positive for West Nile Virus in Wisconsin
State and City of Milwaukee Health Department (MHD) health officials announce that three mosquito pools in the City of Milwaukee in August have tested positive for West Nile virus (WNV). These are the first mosquitoes to test positive for the virus in Wisconsin this year and serve as a reminder that the virus is present in the area and people should be vigilant in protecting themselves against mosquito bites. Historically, human cases of WNV tend to occur and be reported in late summer and early fall within Wisconsin and surrounding States.
“It is important for people to realize that WNV related illness is still a public health concern and, in some instances, can result in serious health effects for the most vulnerable in our communities including children, the elderly and immune-compromised,”said Paul Biedrzycki, Director of Disease Control & Prevention for the MHD. “Citizens should continue to take steps to protect themselves against mosquito bites when spending any significant time outdoors, especially this holiday weekend.”
West Nile virus is spread to people through the bite of an infected mosquito. Mosquitoes become infected with West Nile virus by feeding on infected birds, and then transmit the virus by biting other animals or people. Symptoms of WNV infection include fever, headache and a rash that lasts a few days. A majority of persons will have mild or no symptoms. A small number of persons infected may develop more serious health effects that can include infection of the covering of the brain or spinal cord. There is no specific treatment for WNV infection.
Below are some measures to help decrease your exposure to mosquitoes and prevent West Nile virus infection:
- Limit time spent outside at dawn and dusk, when mosquitoes are most active.
- Apply insect repellant (containing DEET) to clothing as well as exposed skin since mosquitoes may bite through clothing. Follow container directions on application frequency and amount.
- Make sure window and door screens are in good repair to prevent mosquito entry.
- Properly dispose of items that hold water such as tin cans, plastic containers, ceramic pots, or discarded tires.
- Clean roof gutters and downspouts for proper drainage and minimize water stagnation.
- Turn over wheelbarrows, wading pools, boats, and canoes when not in use to prevent water collection.
- Change the water in birdbaths and pet dishes at least every three days to reduce mosquito breeding.
- Clean and chlorinate swimming pools, outdoor saunas and hot tubs; drain water from pool covers.
- Trim tall grass, weeds, and vines since mosquitoes use these areas to rest during hot daylight hours.
- Prevent water from pooling in low-lying areas
Wisconsin documented its first human infections in 2002 with 52 human cases. Last year, there was only one confirmed human case of West Nile virus infection reported in August to the DPH.
For more information on West Nile virus, go to