Mosquito capable of transmitting Zika virus found in Dane County

No evidence of Zika-infected mosquitoes; no known cases of locally transmitted Zika in Midwest

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 - Researchers at the University of Wisconsin Medical Entomology Laboratory (UWMEL) and health officials from the Department of Health Services (DHS) and Public Health Madison-Dane County (PHMDC) announced that the Aedes albopictus mosquito has been found in Dane County.

This is the first documentation of this species of mosquito in Wisconsin. Aedes albopictus is one type of mosquito that is capable of spreading Zika virus, however there is no evidence of Zika-infected mosquitoes in Wisconsin.

The discovery of Aedes albopictus is unlikely to indicate an elevated risk of locally transmitted Zika virus in Wisconsin. Zika virus is primarily spread by the Aedes aegypti mosquito, which survives in warmer climates, and has not been found in Wisconsin or any neighboring states.

Since 2016, UWMEL and DHS have been working closely with local health departments and the federal Centers for Disease Control and Prevention (CDC) to perform active surveillance for Aedes species mosquitoes in Wisconsin. Teams are currently assessing how widespread Aedes albopictus is in Dane County and are looking for the mosquito in other parts of the state.

The Aedes albopictus mosquito has previously been detected in neighboring states including Minnesota and Iowa with no populations of this species becoming established and no known cases of locally transmitted Zika virus in the Midwest. 

“The detection of the Aedes albopictus mosquito in Wisconsin is not a cause for alarm. We can look to nearby states that also have small numbers of these mosquitoes, where Zika virus has not been locally spread,” said State Health Officer Karen McKeown. “However, we want to remind Wisconsin residents to take precautions to prevent mosquito bites. Other serious diseases, including West Nile Virus, are spread by mosquitoes in our state.”

Wisconsin residents at risk for Zika virus infection are people who have traveled or had sexual contact with someone who traveled to locations with active Zika virus transmission (link is external).

The detection of Aedes albopictus in Wisconsin does not change the precautions that DHS recommends (PDF) for people with a possible exposure to Zika virus. Anyone who may have been exposed to Zika should contact their doctor if they experience fever, rash, joint pain, or red eyes within two weeks of possible exposure, and avoid mosquito bites for at least three weeks after they first become ill or after last possible exposure (if there are no symptoms).

To protect yourself from mosquito bites:

  • Wear long-sleeved shirts, long pants, socks, and shoes in order to minimize the amount of  skin that is showing.
  • Use an Environmental Protection Agency (EPA)-registered insect repellent on any exposed skin and apply it according to the label instructions.
  • Mosquitoes may bite through thin clothing, so spraying clothes with a repellent containing permethrin or DEET will give extra protection. Do not use permethrin directly on skin. 
  • Stay and sleep in places with air conditioning and/or screened-in windows.
  • Prevent standing water in your yard by disposing discarded tires, cans, plastic containers; draining standing water from pool or hot tub covers; turning over plastic wading pools and wheelbarrows when not in use; keeping drains, ditches and culverts clean of trash and weeds so water will drain properly; and cleaning gutters to ensure they drain properly.