Why West Nile risk is at the highest levels since 2012 outbreak

The risk for West Nile virus in the suburbs is at its highest level since an outbreak in 2012, officials say.

During the past week, North Shore Mosquito Abatement District employees have found a significant increase in mosquitoes carrying the virus.

"The amount of virus we are detecting in mosquitoes is well above the historical average for this time of year and is also occurring earlier in the season than the average," Director Mark Clifton said in a news release. "These factors indicate that the risk for human West Nile virus infections is elevated and will likely remain elevated through the remainder of August."

The fact that the rates are higher than 2012 is not a good thing. That year, 290 Illinois residents, including 174 in Cook County, became ill with West Nile virus.

Early rains that drenched the Chicago area combined with recent high temperatures have conjured the perfect conditions for the eggs of Culex pipiens, the type of mosquito that carries the virus. The species doesn't develop well during times of heavy rainfall. But as the region has dried out and heated up, warm stagnant water makes for ideal breeding sites, officials say.

The West Nile risk isn't slowing down.

"We're still seeing it increasing, and that's based on trapping information from Wednesday's collection," said North Shore Mosquito Abatement District spokesman Dave Zazra.

Zazra predicted the elevated risk for West Nile virus will continue for several weeks.

Most people infected with the virus show no symptoms. Mild cases may cause a slight fever or headache. More severe infections are marked by a rapid onset of a high fever with head and body aches, disorientation, tremors, convulsions and, in the most severe cases, paralysis or death.

Symptoms typically occur within three to 14 days after the bite from an infected mosquito. People age 50 or older are at the highest risk for serious illness.

Here are a few tips to stay safe from mosquitoes:

• Wear spray repellents such as DEET, Picardin, IR3535, oil of lemon eucalyptus or paramenthane-diol or 2-undecanone.

• Avoid going outside at dawn and dusk, the most active time for mosquitoes.

• Keep your skin covered.

• Eliminate stagnant pools of water of any size on your property.