(AP) — The number of people who have contracted West Nile virus has risen.

Nebraska health officials said Wednesday that they had recorded 11 human cases of West Nile virus in the state for 2013. By Friday, that number had risen to 14.

Four people have been hospitalized with the virus. No one has died this year from the virus.

West Nile is transmitted to people through mosquitoes that feed on an infected bird. Most people with the virus will have no symptoms or only mild flu-like symptoms. A small percentage will develop a serious illness.

Last year, there were 193 human cases of West Nile virus in Nebraska and four deaths.