Public health officials believe a hot, dry weather could increase mosquito activity and increase the risk for West Nile virus.
The primary carrier of West Nile virus in the region is the Culex mosquito, which breeds during hot weather in stagnant water.
"We have samples that have come in...Right now in the Midwest, the most positive samples that have come in have been in the Chicagoland area. There have been 11 positives already," said George Balis, Clarke entomologist.
Lake County health officials claim there have been no West Nile virus positive samples of birds, mosquitoes or humans.
"We have had mosquitoes test positive with West Nile a little earlier than usual," said Latrice Porter Thomas, Cook County Department of Health.
Mosquitoes breed in stagnant water that may be around the home, pools, tires, empty containers and in abandoned property.
Balis says wearing mosquito repellent is imperative for people over 50.
The West Nile virus can be fatal and it is important to seek help.
"Call a doctor if you think you have been infected and have flu like symptoms," said Porter.
The threat of the West Nile virus by the Culex mosquito begins in May and ends in September. If you see a dead bird, contact the health department.