Zika: An Issue in Wisconsin?

With mosquito season nearly upon us and all the headlines about Zika Virus in the news, a big question at the moment is: will Zika be an issue for us in Wisconsin?  Based on what’s known about the Zika Virus and the mosquitoes that transmit it, it’s unlikely that Zika will be a major issue for us in the state.  Certainly, we’ll get cases of Zika in Wisconsin, but these will almost certainly be from individuals that have travelled to areas with active Zika infestations.  Overall, if we look at the bigger picture, a much bigger concern should be deer ticks and Lyme Disease, which affects thousands of Wisconsinites each year.

The Zika situation is an interesting one.  The Zika virus itself was first discovered in Africa in the 1940’s and has been found in parts of the eastern hemisphere for decades.  It wasn’t until very recently that it popped up the western hemisphere.  Because the Zika Virus is linked to a number of serious health issues, such as microcephaly in newborns, it certainly can pose significant health risks—hence the headlines and the concern.

However, the virus is only half of the story—the other half being the mosquito species (vectors) capable of transmitting the virus to humans.  Two mosquito species are associated with Zika virus and other viral diseases such as Chikungunya and Dengue: the Yellow Fever Mosquito (Aedes aegypti) and the Asian Tiger Mosquito (Aedes albopictus).  The good news for us in Wisconsin is that neither of these mosquito species are native to our area, and these species have never been found in the state (additional surveys are being conducted to look for them).  With that said, there may end up being some Zika cases in Wisconsin associated with travel to areas where Zika is widespread, but the absence of the two mosquito vectors responsible for transmission will greatly reduce the chance for transmission occurring within the state.

Estimated range of Aedes albopictus and Aedes aegypti in the United States, early 2016. Map source: Centers for Disease Control and Prevention.
Estimated range of the Asian Tiger Mosquito (Aedes albopictus) and the Yellow fever Mosquito (Aedes aegypti) in the United States, early 2016. Map source: Centers for Disease Control and Prevention.

While the Yellow Fever Mosquito and the Asian Tiger Mosquito don’t occur here, there still is reason to be vigilant about mosquitoes.  With as many as 60 or more different mosquito species in the state, there are a number of other mosquito-borne diseases that do occur in our area.  Our best example would be West Nile Virus transmitted by the Northern House Mosquito (Culex pipiens).  While West Nile cases can vary dramatically from year-to-year, we’ve historically had issues with West Nile in our area, and human deaths have occurred in the past.

Aedes sp. mosquitoes preparing for a blood meal. Photo Credit: Ary Farajollahi, Bugwood.org.

When it comes to mosquitoes in general, there are several approaches to keeping yourself and your family members safe. Around the yard, one of the most important things is to reduce or eliminate standing water to help eliminate mosquito breeding sites.  Toys left out in a sandbox, old tires, clogged gutters, birdbaths with stagnant water and anything else that collects and holds water could be a potential breeding site for mosquitoes.  Using EPA approved repellents, such as DEET, Picaridin, or others when working or relaxing outdoors will offer protection from bites.  Lastly, wearing long sleeves, avoiding outdoor activities during prime mosquito feeding times (dawn/dusk), or simply staying indoors can also protect you from mosquitoes.