By NewsDesk  @bactiman63

San Joaquin County Public Health Services received a report of a human case of St. Louis encephalitis virus (SLEV) in a person from Stockton. The individual is recovering at home.


This is the first reported human case in San Joaquin County since 1973.

In August 2020, the San Joaquin County Mosquito and Vector Control District’s mosquito-borne disease surveillance program discovered SLEV in a group of collected mosquitoes in zip code 95240.

The symptoms and transmission of SLEV are similar to that of the West Nile virus (WNV), but SLEV is less common in California than WNV. WNV and SLEV are both in the flavivirus family and transmitted through mosquito bites. In 2020, there has only been one report of WNV in San Joaquin County – in an asymptomatic blood donor.

People can get infected with St. Louis encephalitis virus from the bite of an infected Culex mosquito. A mosquito becomes infected with SLEV after biting a bird that is infected with the virus. SLEV is not spread from person to person.

Most people infected with SLEV do not have any symptoms or develop mild symptoms including fever, headache, or nausea, which occur up to two weeks after being bitten. In a small number of people, SLEV can cause swelling or inflammation of the brain (encephalitis) which may lead to death. Older adults are the most likely to get very sick if they are infected.