SPRINGFIELD, Ill. (AP) -- The Illinois Department of Public Health has confirmed the third human case of West Nile virus for 2007.
A Madison County man in his 60s has West Nile neuroinvasive disease, a disease that affects the immune system. It's the most severe form of the West Nile virus.
Public Health Director Eric Whitaker says the third human case should make everyone cautious. At this time last year, there were no reported West Nile cases.
The first human case this year was reported in DuPage County on June 15th.
The virus is transmitted through the bite of a mosquito that has fed on an infected bird.
Mosquitos in DuPage, Cook and Tazewell (TAZ'-well) counties have tested positive for West Nile.