The pathogenesis of Japanese encephalitis virus in Culex tritaeniorhynchus mosquitoes

Culex tritaeniorhynchus were inoculated intrathoracically with mosquito and human strains of Japanese encephalitis virus and maintained at 26 °C or 32 °C. Virus titration and localization of viral antigen by avidin-biotin immunoperoxidase staining were done at intervals up to 21 days. Marked differences were noted in the tempo of organ involvement at the 2 temperatures; at both there was initial infection of fat body cells followed by selective infection of the central nervous system (CNS), with consistent infection of cells of the compound eye, patchy involvement of cephalic, thoracic and abdominal ganglia and no infection of Johnston's organ. CNS infection was always present 4 days after infection, when salivary gland involvement was first seen at 32 °C; at 26 °C CNS infection preceded salivary gland infection by 2 weeks. Late involvement of gut cells, pericardial cells and oviducts was also found, with no involvement of muscle.