Rare Human Case Of Encephalitis Confirmed In Long Beach

LONG BEACH, CA — The first documented human case of St. Louis Encephalitis virus in Long Beach since 1984 was discovered on Friday, according to health officials.

As of Nov. 9, this is the 14th case of St. Louis Encephalitis discovered in the state and the first in Los Angeles County in 2023, according to the California West Nile Virus Website.

“The first confirmation of (St. Louis Encephalitis) in Long Beach should serve as a reminder that we need to protect ourselves against mosquitoes,” said Health Officer, Dr. Anissa Davis. “The Health Department encourages everyone to continue reporting issues regarding mosquito control in their area.”

According to Long Beach health officials, the risk of local exposure remains low and officials are taking extra steps to prevent any further spread of the virus that causes St. Louis Encephalitis. The person who has been infected was hospitalized but is now recovering at home and no other suspected cases have been identified.

Encephalitis is spread to people by the bites of culex mosquitoes and is in the same virus family as the West Nile virus with similar symptoms. The virus is not spread from person to person and most infected people will not experience symptoms.

Most people who experience symptoms typically have mild fevers, headaches or nausea. Severe cases of Encephalitis can affect the brain and nervous system, causing stiff neck, confusion, dizziness and sometimes death.

There are currently no vaccines or medicines that treat or prevent encephalitis, but healthcare providers recommend recovery treatments such as staying hydrated, resting and taking medication for pain and fever.

"We are working diligently with healthcare providers to educate the community to prevent more cases of (St. Louis Encephalitis),” said Mayor Rex Richardson. “Mosquito control is a shared responsibility and residents must take an active role in reducing the threat of mosquito-borne illnesses in their neighborhoods.”

Mosquitoes that transmit the virus are most active at dusk and dawn, health officials said. Residents were encouraged to eliminate any standing water in or around their homes to prevent the breeding of additional infected mosquitoes.

Mosquito-borne diseases have been on the rise as the mosquito population exploded this season. Los Angeles County reported two locally transmitted cases of dengue fever less than a month ago. One of those cases was recorded in Long Beach.

According to the California Department of Public Health, human cases of St. Louis Encephalitis are not common in the Golden State and fewer than 10 cases have been reported per year in 1990. Mosquitoes infected with SLEV are most commonly found in the Central Valley and some areas of Southern California, CDPH said.