J — Japanese Encephalitis Virus (JEV)
Japanese encephalitis virus is a mosquito-borne flavivirus endemic in Asia. It is maintained in a zoonotic cycle involving mosquitoes (primarily Culex species), pigs, and water birds. Humans are incidental dead-end hosts.
After mosquito inoculation, JEV replicates in dendritic cells and regional lymph nodes before systemic dissemination. Neuroinvasion likely occurs via hematogenous spread and increased blood–brain barrier permeability during viremia. In the CNS, JEV infects neurons, leading to cell death and neuroinflammation.
Pathogenesis involves both direct neuronal injury and immune-mediated damage. Microglial activation and proinflammatory cytokine production contribute to encephalitic pathology. Most infections are asymptomatic, but a small proportion progress to severe disease.
Clinically, Japanese encephalitis presents with fever, headache, seizures, altered mental status, and movement disorders. Mortality is significant, and survivors often have permanent neurologic sequelae. Vaccination has dramatically reduced incidence in endemic regions.
Research priorities include understanding mechanisms of neuroinvasion, host genetic susceptibility, and long-term neurocognitive outcomes following infection.
Japanese encephalitis virus is a mosquito-borne flavivirus endemic in Asia. It is maintained in a zoonotic cycle involving mosquitoes (primarily Culex species), pigs, and water birds. Humans are incidental dead-end hosts.
After mosquito inoculation, JEV replicates in dendritic cells and regional lymph nodes before systemic dissemination. Neuroinvasion likely occurs via hematogenous spread and increased blood–brain barrier permeability during viremia. In the CNS, JEV infects neurons, leading to cell death and neuroinflammation.
Pathogenesis involves both direct neuronal injury and immune-mediated damage. Microglial activation and proinflammatory cytokine production contribute to encephalitic pathology. Most infections are asymptomatic, but a small proportion progress to severe disease.
Clinically, Japanese encephalitis presents with fever, headache, seizures, altered mental status, and movement disorders. Mortality is significant, and survivors often have permanent neurologic sequelae. Vaccination has dramatically reduced incidence in endemic regions.
Research priorities include understanding mechanisms of neuroinvasion, host genetic susceptibility, and long-term neurocognitive outcomes following infection.