Transmission of Japanese encephalitis virus by Culex gelidus Theobald

Abstract
This study has demonstrated that Japanese encephalitis virus multiplies readily within Culex gelidus and that this mosquito is capable of transmitting the virus to susceptible hosts. The minimal concentration of virus capable of infecting this species was found to be four LD50 per 0.03 ml. of blood. The minimal viral incubation period observed in C. gelidus was 6 days. It was shown that as the dosage of virus ingested by the mosquito increased, the transmission rate also increased, but the length of minimal incubation period decreased. C. gelidus transmitted virus as effectively by probing the host animal as by feeding to repletion. More than one host could be infected by a single infective mosquito in a short period of time if the mosquito was interrupted during the act of feeding. Transmissions of virus by a single infected mosquito were obtained as often as four times in 2 weeks. Attempts to demonstrate mechanical transmission of virus by C. gelidus were negative, as were efforts to obtain transovarian passage of virus by this mosquito.