West Nile Virus in the U.S. Today
As of August 2015, 42 states had reported West Nile virus infections for the year in people, birds, or mosquitoes, according to the CDC. Of the 141 cases of West Nile virus in people reported to the CDC, 82 were classified as neuroinvasive disease (the most severe form of West Nice virus infection, involving the brain and nervous system, such as meningitis or encephalitis) and 59 were classified as non-neuroinvasive disease.
In 2012, the CDC confirmed an outbreak of 1,118 cases of West Nile virus, the highest number of reported cases since the virus was first detected in the U.S. in 1999. Of those, 56% of patients from 47 states developed neuroinvasive disease. Approximately 75% of the cases were reported from five states (Texas, Mississippi, Louisiana, South Dakota, and Oklahoma), and almost half of all cases were reported from Texas, many in the Dallas area.