North Dakota's first line of defense against West Nile virus tastes great with mashed potatoes or corn on the cob.

The Health Department has placed a flock of chickens at eight locations across the state, using the birds as tools to identify the onset of the virus.

Well, it's here.

Two of the chickens tested positive last week for West Nile, and so did a blue jay in Cass County.

"We've known all along that we were going to identify the virus, and it's not going away next year (either)," said Todd Hanson, supervisor of the Mosquito Control Program in Grand Forks, where one of the chickens tested positive. The other was in Stutsman County, near Jamestown.

Tracy Miller, manager of the West Nile Virus Surveillance Program for the state health department, said they've been testing the white leghorn chickens each week for about a month and a half. That some have now tested positive was not a surprise.

"We didn't think we would have a season where we didn't identify West Nile virus," Miller said. "It's a reminder to the public that once again it's here, we do have viral activity, and people need to continue taking precautions against mosquito bites."

Last year at this time three birds had tested positive for the virus, Miller said. Also at this time last year, 287 human samples were tested, with no positives. This year, 281 human samples have come back negative, Miller said.

Health department officials said there was no way to gauge how widespread West Nile might be in North Dakota during this mosquito season. Mike Trythall, a microbiologist for the department, said mosquito counts have been average compared to years past. The number of culex tarsalis mosquitoes - those most commonly associated with transmitting arboviruses - has been going up recently, but the populations are in the normal range.

West Nile was first found in humans in North Dakota in 2002. That year, 17 people were infected, two of them dying as a result. In 2003, the virus infected more than 600 people, killing five. Last year, the number tapered to 20 cases. Still, two people died in North Dakota because of West Nile in 2004.

"From our standpoint, that's still two too many," Miller said. She said people ought to use insect repellents, limit outdoor activities during dawn and dusk, and eliminate stagnant water around the yard.

The USDA's division of wildlife services is assisting the state health department with the "sentinel chicken" program. Flocks of 12 chickens have been placed near Bismarck, Jamestown, Fargo, Grand Forks, Devils Lake, Minot, Williston and Dickinson.

Ryan Powers, a wildlife disease biologist with the USDA, said chickens are used because they typically don't develop clinical illnesses after being infected with West Nile and don't have high mortality rates. The chickens also don't usually infect other members of the flock, Powers said.

The chickens that tested positive were likely infected two weeks ago, Powers said.