OMAHA, Neb. -- Two more cases of West Nile Virus have been reported in the state, bringing the total cases reported this year to 25, according to the Nebraska Department of Health and Human Services.

The new cases are residents of Custer and Keith counties.

West Nile is transmitted through the bite of a mosquito that has picked up the virus by feeding on an infected bird. Late August is peak transmission time for West Nile.

Most people who are infected by a mosquito have no symptoms or only mild flu-like symptoms.

Fewer than one out of 150 people who get bitten by an infected mosquito and become infected will get seriously ill.

However, people older than 50 and those with weakened immune systems are especially vulnerable to the disease and are more likely to experience serious consequences.