100 sentinel chickens were placed throughout North Dakota May 23. Health officials began drawing weekly blood samples June 20. Those found to be infected with the West Nile virus have been removed from the flocks.

The chicken belonged to one of the seven sentinel flocks the health department and the US Department of Agriculture have established around the state as a surveillance tool for the virus, said Tracy Miller, manager of the West Nile Virus Surveillance Program at the department of health.

The flocks are tested once a week to determine if they have been exposed to West Nile virus. On July 14, it was determined chickens in Grand Forks and Stutsman counties had West Nile virus. A blue jay from Cass County also has tested positive.

"While we didn't think there would be a season that we wouldn't find it, it's a reminder that it is here," Miller said of the virus. She urged people to continue to take precautions against mosquitoes.

One Positive Horse

As of July 15, 23 horses have been tested, with one positive horse identified. In addition, 281 samples from humans have been submitted to the department. All of those have tested negative for the disease.

In 2004, 20 human cases of West Nile virus and two deaths were reported to the department.

Ryan Powers, a wildlife disease biologist assisting the department of health with the chicken program, said 100 chickens were placed throughout the state May 23. They began drawing weekly blood samples from the chickens June 20.

The chickens with the disease have been removed from the flocks. Other flocks are located in Bismarck, Jamestown, Fargo, Devils Lake, Minot, Williston and Dickinson.

Fever, Dizziness, Fatigue

West Nile virus causes fever, dizziness, fatigue, stiff neck and headaches that last two to three days, said Mike Trythall, virology and immunology supervisor with the Department of Health.

The elderly and those with weakened immune systems are particularly vulnerable to being infected.

Todd Hanson, supervisor of the Mosquito Control Program in Grand Forks, said the program will not change because of the announcement.

"We've been running the program as if the virus was here," he said. "We've known all along we were going to identify it this year."

The local program includes public education, surveillance, breeding site reduction, larviciding and adulticiding, he said. Residential areas are sprayed whenever trap counts reach 100, although several times this year Grand Forks and East Grand Forks have sprayed when trap counts were well below 100.