SLEV (St. Louis encephalitis virus)

St. Louis encephalitis virus (SLEV) is a virus transmitted primarily through mosquito bites, notably from infected Culex mosquitoes. It can cause inflammation of the brain (encephalitis), leading to symptoms like fever, headache, confusion, and in severe cases, seizures or paralysis. Most people experience mild or no symptoms, but older adults and those with weakened immune systems are at higher risk for serious illness. The virus mainly circulates in bird populations, with mosquitoes acting as the bridge to humans. Preventive measures include mosquito control and avoiding mosquito bites, especially during peak mosquito activity seasons.