Like St. Louis encephalitis virus, most people infected by WNV experience mild or unrecognized symptoms while a minority experience illness with fever. More rarely victims develop encephalitis, paralysis and may die. The greatest number of human cases of West Nile disease seen in Florida was during 2003, a total of 94 cases. Despite having been first detected in Indian River sentinel chickens in 2001, and many times in the following years, there has not yet been a human case of disease caused by West Nile virus in this county.