Cases occur in Houston and Harris County in the summer and early fall.
Encephalitis is an infection of the brain. This particular form of encephalitis is transmitted to humans by a bite of the Culex mosquito that is infected with the SLE virus. Only one in 200 people who are infected with SLE following a bite will become ill. The incubation period is 5 to 7 days. A person may experience all or only a few of these symptoms.