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Zika virus - What you need to know

Zika virus infection is a disease transmitted to people primarily through the bite of an infected Aedes species mosquito.

Symptoms of the disease are usually mild and include fever, rash, joint pain, and red eyes. Most people don’t have any symptoms. Serious illness and death are rare. For this reason, many people are not even aware they have the disease.

There is no vaccine or medication treatment for Zika virus illness. Once a person has the disease, he/she may be protected from future infections. Zika virus can also be spread through sexual contact and blood transfusions.

Of most concern with Zika virus infection is the potential for transmission of the virus from the mother to the baby during pregnancy. Zika virus infection during pregnancy can cause a serious birth defect called microcephaly (a medical condition in which the size of the head is smaller than normal because the brain has not developed properly or has stopped growing) as well as other serious brain defects. Zika virus infection has also been associated with an increase incidence of Guillain-Barre’ (a rare disorder in which the body’s immune system attacks the nerves).

The first identified case of human Zika virus infection occurred in 1954 in Africa. Since then, there have been outbreaks in many areas of Africa, Southeast Asia and the Pacific Islands. The virus has recently spread to Central and South America and the Caribbean.

Currently, in the continental United States, there have been 472 travel-associated cases of Zika virus infection reported and no local vector-borne cases. There has recently been one travel-associated Zika virus infection reported in Wisconsin. There have been no cases of Zika virus in St. Croix County.

The Aedes species mosquito that carries Zika virus is not found in Wisconsin. However, other types of mosquitoes that spread other viruses are present in Wisconsin and in St. Croix County. One example is the Culex species that carries West Nile Virus (WNV). The majority of people with WNV infection will not have any symptoms or symptoms will be very mild and include fever, headache, muscle pain, skin rash, and sensitivity to light.

How do you protect yourself from Zika virus infection and other mosquito transmitted infections?

The number one way you can protect yourself from Zika virus is to avoid travel to areas where vector-borne (mosquito transmission) has occurred such as Central and South America and the Caribbean. This is particularly important if a woman is pregnant or planning to become pregnant.

Other protective steps one can take to avoid mosquito-transmitted infections include:

  • Use an effective mosquito repellent (do not use insect repellent on babies younger than two months old;
  • Wear long-sleeved shirts, long pants, socks, and shoes and dress your child in clothing that covers arms and legs;
  • Spray clothing with a repellent containing DEET or permethrin;
  • Avoid being outside during times when mosquitoes are most active such as dusk and dawn; and 
  • Keep home window screens repaired so mosquitoes cannot enter.

Standing water provides a perfect habitat for mosquitoes to multiply so it is very important to:

  • Dispose of old tires, cans, or plastic containers left outside that can hold standing water;
  • Drain water from hot tub and pool covers;
  • Turn over plastic wading pools and wheel barrows if not in use;
  • Change the water in bird baths, pet dishes and wading pools every three days;
  • Clean gutters to make sure they drain properly.

What is St. Croix County Public Health doing to reduce the incidence of vector-borne diseases?

For the past several years, Public Health has contracted with the La Crosse County Vector Control Program to provide vector control services to St. Croix County. The goal of the program is to prevent human and animal infection by interrupting the vector-host cycle. Specific program activities involve monitoring for potential mosquito habitat sites such as old tires, and buckets and other receptacles that hold standing water. Whenever possible, these habitat sites are eliminated. If elimination isn’t possible, the containers or receptacles are treated with a targeted insecticide that kills the larvae.

Places such as ditches, storm sewers, woodland, and ponds are also monitored as they can be very productive habitat for Culex mosquitoes (the mosquito that transmits West Nile Virus). In cases where unattended birdbaths, wading pools or similar smaller numbers of containers were found, vector program staff would assist residents with clean up and provide educational materials concerning mosquitoes, mosquito-borne disease and habitat reduction.

The vector control staff also set up ovi collection traps that enable identification of the types of mosquitoes in the area.

In 2015, 513 mosquito-borne disease habitat sites were monitored and 345 traps were placed in St. Croix County.

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For more information, call St. Croix County Public Health at 715-246- 8263 or 715-246- 8363.