Stanislaus County, CA health officials have reported a human case of the mosquito-borne viral disease, St. Louis encephalitis.
The male patient in his 70s is the first confirmed human St. Louis encephalitis virus (SLEV) infection in Stanislaus County for 2017, according to Dr. Julie Vaishampayan, Stanislaus County Public Health Officer.
“He had symptoms and was tested in September; confirmatory testing was performed first by the California Department of Public Health followed by the Centers for Disease Control and Prevention.” This is the second person in California testing positive for the virus in 2017.
The virus was identified in mosquitoes in Stanislaus County in August of this year, the first detection in over four decades. To date in 2017, SLEV has been detected in mosquitoes in 14 California counties.
SLEV is transmitted to humans by the bite of an infected mosquito. Most people infected with SLEV have no apparent illness. Initial symptoms of those who become ill may include fever, headache, nausea, vomiting, and tiredness. Severe neuroinvasive disease (often involving encephalitis, an inflammation of the brain) occurs more commonly in older adults. Like West Nile virus, there is no vaccine or specific treatment for SLEV infection.