Much like a canary in coal mines, chickens will be placed across Utah County to be an early warning system for the West Nile virus.

Monday, the Utah County Health Department kicked off the West Nile season, as chickens were distributed to mosquito abatement agencies across the state. A total of 450 chickens were distributed across the state, with 30-50 birds staying in Utah County. Utah started using chickens in 2004.

"They have been a real good indicator for us," said Robert Mower, Utah County Mosquito Abatement manager. "They normally show the virus two to four weeks earlier than humans."

The chickens act as a vector: they can catch and carry the disease, but they will not die or have any adverse consequences from it. The health department will be taking blood samples from the chickens in the beginning half of June to test for the virus. If a chicken is tested and has the virus, it is taken from the group and replaced with a new chicken.

The birds will be placed where the mosquito abatement agencies expect to see the virus first. The area of most concern in Utah County is around Utah Lake.

"If we could figure out the psychology of the mosquito, we would understand a lot more about them [and where they would go]," said Lance Madigan, public information officer for Utah County Health Department.

The virus normally starts showing up in humans at the end of July, especially around the Pioneer Day Holiday. West Nile requires there to be a short period of hot temperatures. That coupled with a lot of people spending time outside camping and doing other activities increase the chance for a human to catch the virus, Mower explained.

Two breeds of mosquitoes carry the virus, but only one bites humans, the culex tarsalis breed. This breed is active from dusk to dawn, especially from dusk to about midnight. The other breed bites animals, especially larger ones like horses. Eighteen horses caught the virus last year.

In past years, mosquito abatement programs have also tested large birds, but this year the state lab does not have the funds to test wild birds.

"So the chickens are even more important," Madigan said.

In addition to chickens, the Utah County Mosquito Abatement Department will set up traps using dry ice. As the dry ice melts, it releases carbon dioxide, which attracts mosquitoes. The trapped mosquitoes are then tested for the virus.

In 2006, 65 human cases of the West Nile virus were reported in Utah County. Last year this number was reduced dramatically to two.

80 percent of those infected with West Nile don't show any symptoms. Out of the 20 percent that do show symptoms, only about 1 percent show severe symptoms.

The first cases of West Nile virus happened in 1999 in New York. The virus started showing up in Utah around 2003.

The birds will be treated as humanely as possible. They will be given food and water regularly.

Madigan urged people to start mosquito proofing their homes and preparing for mosquito season, by wearing mosquito repellent with DEET in it. People also need to remove sources of standing water from around homes where mosquitoes could breed and to fix holes in screens, windows, and any place else around the house where mosquitoes could get in.

For more information, visit http://health.utah.gov/epi/diseases/wnv/.

Copyright Brigham Young University 20 May 2008