🦠microbiology review

St. Louis encephalitis (SLE)

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

St. Louis encephalitis (SLE) is a viral disease that causes inflammation of the brain and is transmitted by mosquitoes. It predominantly affects individuals in North America, particularly in the United States.

5 Must Know Facts For Your Next Test

  1. SLE is caused by the St. Louis encephalitis virus (SLEV), a member of the Flavivirus genus.
  2. The primary vectors for SLEV transmission are Culex mosquitoes.
  3. Symptoms of SLE can range from mild flu-like illness to severe neurological conditions, including encephalitis, coma, or death.
  4. There is no specific antiviral treatment for SLE; management focuses on supportive care to relieve symptoms.
  5. Older adults and those with weakened immune systems are at higher risk for severe complications from SLE.

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