WATERLOO - The mosquito season is almost upon the Cedar Valley, and the Black Hawk County Health Department is gearing up.

Sentinel chickens, designed to alert health officials when West Nile virus has made its way to the county, arrived at the Sunrise Petting Zoo Wednesday. The chickens are tested each week to determine if they have been infected.

Mark Linda, a Black Hawk County environmental health manager, expects cases of human infection to be held to a minimum this year if Iowa follows the trend of other states.

"The science on this is not complete, but the theory is that many people have developed resistance so the attack rate drops off," he said. "It is still important to prevent mosquito bites. It is still a disease of concern for us."

The county will once again collect dead crows and blue jays for analysis at the University of Iowa Hygienic Lab, though testing will be done on a limited basis. Linda said the department can only collect and send in one bird at a time. A second bird cannot be sent for testing until the first bird tests negative for West Nile.

Once a bird tests positive, no additional tests will be run.

Linda said light traps will also be set in Waterloo, Cedar Falls and Evansdale. Trapped mosquitoes will be sent to Iowa State University, where they will be sorted by species.

"The intent of this surveillance is to maintain a comparative analysis of the types of mosquitoes we have in our area," Linda said. "We have about 45 different varieties and about six or seven are of concern. By looking at the mosquitoes we can learn about their hatch habits and know better how to deal with them."

Regardless of requests, Linda said, the county will hold firm on its decision not to spray for adult mosquitoes. Instead health officials will continue to apply larvacide in Waterloo, Cedar Falls and Evansdale. Larvacide is targeted at unborn mosquitoes and has been proven to work more effectively than spraying, Linda said.

"The one thing you can do to protect yourself from bites and infection is to rid yourself of your own breeding sites," Linda said. "Empty the coffee cans, clean out the roof drains. Take a look around. If water has the opportunity to stand for a couple of weeks it will breed mosquitoes."

Contact Emily Christensen at (319) 291-1482 or emily.christensen@wcfcourier.com.