Human cases of West Nile virus (WNV) confirmed in Chester County. Human cases of West Nile virus (WNV) confirmed in Chester County. A human has tested positive for West Nile virus (WNV) in Chester County. According to the state officials it is the first case of WNV in the local area in some time. A Salt Lake County resident has been hospitalized with a potentially deadly form of West Nile virus (WNV), the first known case in the county this year.
