Japanese Encephalitis

JE is a neurotropic flavivirus CNS infection distributed in East/Southeast Asia, mosquito-borne, summer-autumn. Acute onset with high fever/altered consciousness/convulsions/spasticity/meningeal signs; severe cases leave sequelae. High mortality/disability in children. Isolated in Japan (1934); in China (1939); renamed epidemic B encephalitis after 1949.

Common Symptoms

Involuntary movement; dull expression; incontinence; apathy; dementia; convulsion; wheezing; low fever; intestinal paralysis

Causes and Pathogenesis

Flavivirus, 40 nm (30 nm core), icosahedral, +ssRNA ~10.9 kb. Neurotropic, cytoplasmic replication; heat/ether/chloroform/protease/bile/acid-sensitive (100°C/2 min, 56°C/30 min); cold/dry-resistant (years lyophilized 4°C). Grows in mouse brain/chick embryo/monkey kidney/Hela; optimal mosquito replication 25-30°C. Antigenically stable with cross-reactivity among group-B arboviruses; neutralization tests are specific. TCM: summer-heat epidemic toxin; heat-phlegm-wind triad. Pathology: neuronal degeneration/necrosis/Nissl loss/softening cavities/calcification; widespread lesions from cortex to spinal cord (worst in brainstem/thalamus). Pathogenesis: mosquito bite → local monocyte-macrophage replication → viremia → CNS/liver/heart/lung/kidney. Outcome depends on immunity/BBB/cysticercosis load. Immune-mediated vasculitis (perivascular cuffing) and CIC (64.64% acute/42.62% recovery) with C3 consumption. Gross: congested leptomeninges, widened sulci, miliary softening foci (parietal/thalamus worst). Microscopy: lymphocyte/mononuclear perivascular cuffs, gliosis, endothelial swelling/necrosis/thrombosis.

Treatment

Drug therapy, rehabilitation

Preventive Measures

Early isolation; monitor vital signs/pupils/breathing; eliminate mosquito breeding sites; vaccinate susceptible children (<10 y) 1-2 months before season. Killed vaccine: neutralizing/CFT/HI antibodies appear 2 weeks post-course, peak at 1 month. Maternal IgG protects newborns; start vaccination at 8 months. Personal mosquito protection.

Department to Visit

It is recommended to visit the Infectious Diseases department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.