No flavivirus-specific antiviral has completed successful phase III trials
Empiric acyclovir covers HSV until excluded (standard of care)
Ribavirin, IFN-alpha, IVIG all lack RCT evidence for SLE
Vaccine status
No licensed SLE vaccine available
Japanese encephalitis vaccine (cross-protective flavivirus) has theoretical benefit but not validated for SLE protection
Rationale for supportive care priorities
Fever control
Pyrexia worsens neuronal excitability and metabolic demand
Each 1 C increase in temperature raises cerebral metabolic rate approximately 6-8%
Seizure control
Seizures increase ICP and neuronal injury
Non-convulsive status epilepticus associated with worse outcomes
Normoglycemia
Both hypo- and hyperglycemia worsen neurologic outcomes
Target glucose 7.8-10 mmol/l in critical illness
Long-term rehabilitation
Neuropsychological testing at discharge and follow-up
Documents baseline for recovery monitoring
Guides rehabilitation planning
Cognitive rehabilitation
May improve attention and processing speed deficits
Structured programs for working memory training
Physical and occupational therapy
For motor deficits, tremor, and functional impairment
Early mobilization reduces complications of immobility
Psychiatric support
Depression screening post-SLE
SSRIs appropriate for post-encephalitis depression
Patient Discharge Instructions
copy discharge instructions
Diagnosis and nature of illness
Diagnosis: St. Louis encephalitis — a viral brain infection transmitted by mosquito bites
Caused by St. Louis encephalitis virus (SLEV), a flavivirus
No person-to-person transmission; cannot spread from person to person
No vaccine available to prevent infection
Medications at discharge
Take all prescribed medications exactly as directed
Antiepileptic medication: do not stop without physician advice even if feeling well
Acetaminophen for fever or headache as needed
Do not drive or operate heavy machinery while taking antiepileptic medications
Activity restrictions
Activity as tolerated
No driving until seizure-free for the period required by your province or state law
Avoid swimming or heights until cleared by neurology
Fatigue is expected; increase activity gradually
Mosquito bite prevention
Personal protection measures
Apply DEET-containing insect repellent (20-30% DEET) to exposed skin
Wear long sleeves and pants especially at dusk and dawn when Culex mosquitoes feed
Treat clothing with permethrin for added protection
Environmental measures
Eliminate standing water around the home (buckets, birdbaths, flowerpot trays)
Repair or install window and door screens
Use air conditioning when available
Expected recovery timeline
Recovery information
Mild cases may resolve within weeks
Neuroinvasive disease recovery may take months to years
Cognitive effects including memory and attention problems may persist
Fatigue and depression are common after encephalitis
Neurocognitive rehabilitation
Neuropsychological testing may be recommended
Memory aids and compensatory strategies can help during recovery
Follow-up appointments
Neurology follow-up within 1-2 weeks of discharge
Earlier if seizures occur or neurologic status changes
Repeat assessment at 6 and 12 months for neurocognitive evaluation
Primary care follow-up within 1 week
Return to emergency department immediately if
Red flag symptoms requiring immediate return
New or returning seizures
Worsening confusion, agitation, or inability to wake
New weakness, numbness, or difficulty speaking
High fever (> 38.5 C) returning after discharge
Severe headache worse than prior
Difficulty breathing or swallowing
Vision changes
References
Guidelines and key sources
Curren EJ, Lindsey NP, Fischer M, Hills SL. St. Louis Encephalitis Virus Disease in the United States, 2003-2017. Am J Trop Med Hyg. 2018. PMID 30182919
US surveillance data 2003-2017; epidemiology, age distribution, outcomes
Solomon T. Flavivirus Encephalitis. N Engl J Med. 2004. https://www.nejm.org/doi/full/10.1056/NEJMra030476
Comprehensive review of flaviviral CNS disease including SLE
Bloch KC, Glaser C, Gaston D, Venkatesan A. State of the Art: Acute Encephalitis. Clin Infect Dis. 2023. PMID 37485952
IDSA-aligned systematic approach to encephalitis diagnosis and management
Updated comprehensive encephalitis review including outcomes and sequelae
Venkatesan A, Michael BD, Probasco JC, Geocadin RG, Solomon T. Acute Encephalitis in Immunocompetent Adults. Lancet. 2019. PMID 30782344
Evidence-based management framework for viral encephalitis
Venkat H, Krow-Lucal E, Kretschmer M, et al. Comparison of SLE and WNV neuroinvasive disease during concurrent outbreaks, Arizona 2015. Vector Borne Zoonotic Dis. 2020. PMID 32251616
Clinical differentiation of SLE vs. WNV; rash prevalence data
Rahal JJ, Anderson J, Rosenberg C, Reagan T, Thompson LL. Effect of Interferon-Alpha2b Therapy on St. Louis Viral Meningoencephalitis: Pilot Study. J Infect Dis. 2004. PMID 15319857
Only clinical trial data for IFN therapy in SLE
Hartmann CA, Vikram HR, Seville MT, et al. Neuroinvasive SLE in Solid Organ Transplant Recipients. Am J Transplant. 2017. PMID 28452107
Immunocompromised host presentation and outcomes
Greve KW, Houston RJ, Adams D, et al. Neurobehavioural Consequences of St. Louis Encephalitis Infection. Brain Injury. 2002. PMID 12419004
Piantadosi A, Kanjilal S. Diagnostic Approach for Arboviral Infections in the United States. J Clin Microbiol. 2020. PMID 32938736
Arboviral testing algorithm; PRNT and IgM ELISA guidance
Miller JM, Binnicker MJ, Campbell S, et al. IDSA/ASM Guide to Microbiology Laboratory Utilization 2024. Clin Infect Dis. 2024. https://academic.oup.com/cid/article-lookup/doi/10.1093/cid/ciae104
Laboratory testing guidance for arboviral diagnosis
CDC West Nile Virus Surveillance and Control Guidelines 2025. https://www.cdc.gov/mosquitoes/media/pdfs/2024/09/westnilevirus-surveillancecontrolguidelines_508.pdf
Vector control and public health reporting framework
Danforth ME, Snyder RE, Feiszli T, et al. Re-Emergence of SLE in California, 2015-2020. PLoS Negl Trop Dis. 2022. PMID 35939506
Geographic re-emergence; California epidemiology
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.