Two cases of West Nile virus have been reported in Nebraska, the first this year.

The two are both males between the ages of 26 and 64, one from Lincoln County and the other from Platte County, according to the Nebraska Health and Human Services System.

West Nile is transmitted through the bite of a mosquito that has picked up the virus by feeding on an infected bird.

The first mosquitoes to test positive for West Nile virus were found in Holt County in the north-central part of Nebraska. No birds have tested positive.

Last year, 255 human cases of the disease were reported, compared with 188 in 2005, 57 in 2004, 2,366 in 2003 and 174 in 2002. There were no cases before 2002, the year the disease found its way to Nebraska from the East Coast. At least two deaths were reported last year.

Less than one out of 150 people who get bitten by an infected mosquito and become infected will get seriously ill. West Nile fever includes flulike symptoms such as fever and muscle weakness. Symptoms of West Nile encephalitis include inflammation of the brain, disorientation, convulsions and paralysis.

People over 50 and those with weak immune systems are especially vulnerable to the disease.