Fifty-one percent of the cases of West Nile virus were classified as neuroinvasive disease such as meningitis, encephalitis or West Nile poliomyelitis and 49 percent were classified as non-neuroinvasive disease, or headache, muscle pain, joint pain, rash or gastrointestinal symptoms.
"The 4,531 cases reported thus far in 2012 is the highest number of West Nile virus disease cases reported to CDC through the third week in October since 2003," the CDC said on its website. "Almost 70 percent of the cases have been reported from eight states -- Texas, California, Louisiana, Mississippi, Illinois, South Dakota, Michigan and Oklahoma -- with one-third, or 1,580, of all cases reported in Texas."
However, the numbers will be diminishing because of colder weather will result in the fewer mosquitoes.
"There are no absolutes, but as there are more frosts and freezes the mosquitoes will disappear because they hibernate or lie dormant, so the risk of being bitten by an infected mosquito goes down, but there are always micro-climates which are protected from the frost," Roger Nasci of the CDC told UPI.
"Of course, in the South, the mosquito season begins earlier and extends longer. In some places in the South, West Nile is reported year-round, but the peak activity is August, September and October."