Wisconsin birds test positive for West Nile Virus

Protect yourself against mosquito bites

Wisconsin State Farmer
Some mosquitoes can spread illnesses, such as West Nile virus and the Zika virus. The second mosquito capable of carrying the Zika virus was found in the state.

MADISON -The Wisconsin Department of Health Services (DHS) reports 12 birds found in eight counties in the state have tested positive for West Nile virus since surveillance for the mosquito-transmitted virus began May 1.

“The positive birds mean that Wisconsin residents need to be more vigilant in their personal protective measures to prevent mosquito bites,” Karen McKeown, Wisconsin State Health Officer of the DHS Division of Public Health, said.

West Nile virus is spread to humans through the bite of an infected mosquito. Mosquitoes acquire the virus by feeding on infected birds.

The first bird that tested positive for West Nile virus in the state was collected in mid-May.

“This timing is a couple of weeks earlier in the year than we typically detect the first positive bird,” Rebecca Osborn, Vectorborne Disease Epidemiologist, said. “This doesn’t necessarily mean that we will see more human cases in 2017, but it does indicate that West Nile virus is already active throughout most of the state and that residents should take some simple steps to protect themselves against mosquito bites.”

DHS recommendations 

Limit time spent outside at dawn and dusk, when mosquitoes are most active.

Apply an EPA-registered insect repellent to clothing as well as exposed skin since mosquitoes may bite through clothing.

Make sure window and door screens are in good repair to prevent mosquito entry.

Properly dispose of items around your property that hold water, such as tin cans, plastic containers, ceramic pots, or discarded tires.

Clean roof gutters and downspouts for proper drainage.

Turn over wheelbarrows, wading pools, boats, and canoes when not in use.

Change the water in birdbaths and pet dishes at least every three days.

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.

Landscape to prevent water from pooling in low-lying areas.


The majority of people (80 percent) who are infected with West Nile virus do not get sick. Those who do become ill usually experience mild symptoms such as fever, headache, muscle ache, rash, and fatigue.

Less than 1 percent of people infected with the virus get seriously ill with symptoms that include high fever, muscle weakness, stiff neck, disorientation, mental confusion, tremors, confusion, paralysis, and coma.

Older adults and those with compromised immune systems are at greater risk of developing central nervous system illness that can be fatal.

DHS has monitored the spread of West Nile virus since 2001 among wild birds, horses, mosquitoes, and people. During 2002, the state documented its first human infections with 52 cases reported that year. During 2016, 13 cases of West Nile virus infection were reported among Wisconsin residents.

West Nile virus infections in humans have been reported from June through October; however, most reported becoming ill with West Nile virus in August and September.

The DHS Division of Public Health will continue surveillance for West Nile virus until the end of the mosquito season. To report a sick or dead crow, blue jay, or raven, please call the Dead Bird Reporting Hotline at 1-800-433-1610.