What is the treatment and prevention for Japanese encephalitis?

Treatment and Prevention of Japanese Encephalitis

Treatment Approach

There is no specific antiviral treatment for Japanese encephalitis; management is limited to supportive care focusing on symptom management and complication prevention. 1

The supportive care approach includes:

• Maintaining adequate hydration with intravenous fluids 1
• Providing respiratory support in severe cases with declining consciousness 1
• Monitoring and managing increased intracranial pressure 1
• Administering anticonvulsants for seizure control when necessary 1

Several treatments have been investigated but found ineffective:

• Corticosteroids do not improve outcomes 1
• Interferon alpha-2a has shown no benefit 1
• Ribavirin is not recommended 1
• Minocycline is ineffective 1
• Intravenous immunoglobulin is not recommended 1

Prevention Strategies

Prevention is critical given the lack of specific treatment and high morbidity/mortality:

Vaccination

• Vaccination is the most effective prevention strategy for Japanese encephalitis 1
• Recommended for:
  • Residents in endemic areas, particularly children 1
  • Travelers staying for prolonged periods in rural areas with active JE virus transmission 1

Available vaccines include:

• Purified formalin-inactivated mouse brain-derived vaccine 2
• Live attenuated vaccine (SA 14-14-2), which is reported to be safe, effective, and economical 2
• Chimeric recombinant attenuated JE vaccines (under investigation) 2

Personal Protection Measures

• Use insect repellents containing DEET, picaridin, or IR3535 1
• Wear long-sleeved shirts and long pants 1
• Stay in accommodations with air conditioning or window/door screens 1

Prognosis and Complications

Japanese encephalitis has significant health impacts:

• Case-fatality ratio of 20-30% 1
• Among survivors, 30-50% experience neurologic or psychiatric sequelae even years after infection 1
• Common sequelae include:
  • Seizures 1
  • Upper and lower motor neuron weakness 1
  • Cerebellar and extrapyramidal signs 1
  • Movement disorders, especially transient Parkinsonian features and dystonia in 20-60% of patients 2

Diagnostic Approach

Accurate diagnosis is essential for appropriate management:

• IgM antibody-capture enzyme-linked immunosorbent assay (MAC ELISA) is the preferred diagnostic test 1
• JE virus IgM antibodies can be detected in CSF within 4 days of symptom onset 1
• Presence of JE virus IgM antibodies in CSF provides evidence of JE virus as the cause of neurologic illness 1
• Plaque reduction neutralization tests (PRNTs) can confirm recent infection 1
• MRI typically shows involvement of thalamus, corpus striatum, brainstem, and spinal cord 2

Common Pitfalls and Considerations

• JE is often misdiagnosed due to similarity with other viral encephalitides 3
• For every symptomatic case, there are 25-1000 subclinical infections 2
• Coinfection with cysticercosis may occur due to the role of pigs in both disease cycles 2
• In endemic areas, JE primarily affects children, but in newly affected areas, both adults and children are at risk due to lack of protective antibodies 4