Saint Louis encephalitis virus
From IDWiki
Background
- Single-stranded positive-sense enveloped virus in the family Flaviviridae and genus Flavivirus
- Reservoir is birds
- Vector-borne, transmitted by Culex mosquitoes
- Outbreaks have occurred in the US, Canada, and Mexico, with sporadic cases in Central and South America
Clinical Manifestations
- Incubation period 4 to 21 days
- Risk of encephalitis is highest in older age >60 years
- Presents with non-specific febrile illness with severe headache and meningismus, followed by focal neurological deficits including brainstem, cerebellum, and cranial nerves
- Tremors of the eyelids, tongue, lips, and extremities
- Seizures are uncommon
- Usually no motor or sensory deficits, but may develop urinary symptoms
Prognosis and Complications
- Mortality 5-15%, but higher in the elderly
- Up to half of survivors have neuropsychiatric symptoms persisting at 3 years
Diagnosis
- Serology demonstrating IgM in CSF or serum
Management
- Supportive
