In addition, two blood donors -- one each from Douglas and Stanton Counties -- have tested positive. The donors had no symptoms when they gave blood. The blood was not used.

Blood donations have been checked for the virus since July 2003, said Marla Augustine, a spokeswoman for the Nebraska Health and Human Services System.

Avoid Mosquito Bites

Also testing positive were a horse from Cherry County and mosquito pools from 10 counties -- Cherry, Dawes, Dawson, Garden, Garfield, Holt, Lincoln, Madison, Scotts Bluff and Sheridan.

In Iowa, dead birds have tested positive in seven counties, including Pottawattamie and Woodbury, which also has had sentinel chickens with the virus, according to the Iowa Department of Public Health. No cases in humans have been reported in Iowa.

Wayne Kramer, Nebraska's state entomologist, said the positive test results indicate that the virus is active in the state and that people should take precautions to avoid being bitten by mosquitoes. People get the virus from mosquitoes that have bitten infected birds.

In the past few years, Kramer said, human cases of the disease have peaked in late August and early September. However, West Nile activity has been low this year in Nebraska and Iowa compared with last year, and it's been considerably less than in 2003.