Japanese encephalitis
General description
The Japanese encephalitis virus, a member of the Flaviviridae family, involves a lifecycle with mosquitoes and pigs serving as vectors. It is prevalent in the Far East, Southeast Asia, and South Asia.
The disease often manifests as meningoencephalitis, characterized by high fever, headache, nausea, vomiting, and dizziness. Additional symptoms include rigidity of the neck, impaired consciousness, and a range of neurological disorders such as altered muscle tone, cranial nerve symptoms, involuntary movements, tremors, paralysis, and pathological reflexes.
Basal ganglia and thalamus involvements
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Thalamus
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Putamen
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Globus pallidus
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Caudate nucleus
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Substantia nigra
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CerebrumTemporal lobeHippocampus
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CerebrumCerebral white matter
MRI scans of individuals with Japanese encephalitis reveal affected areas in the basal ganglia, thalamus, and substantia nigra bilaterally, with occasional spread to the hippocampus and cerebral cortex. Typically, the cerebral white matter remains preserved.
These imaging findings bear similarities to those seen in cases of West Nile virus encephalitis and Murray Valley encephalitis, which are also caused by members of the Flaviviridae family.