Antigen distribution pattern of Japanese encephalitis virus in Cubex tritaeniorhynchus, C-vishnui & C-pseudovishnui

Distribution of Japanese encephalitis (JE) virus antigen in different tissu es of mosquitoes was studied in three species viz, Culex tritaeniorhynchus, C. Vishnui and C. pseudovishnui. Overall per cent positivity was higher in the intrathoracically infected as compared to the orally infected mosquito es, suggesting the existence of a midgut barrier. The cells at the junction of the foregut-midgut, and midgut-hindgut showed intense fluorescence from the second day post feeding onwards, This suggests that the dissemination of virus takes place from these regions of the gut. A small number of saliv ary glands were found negative even though fluorescence was seen in the res pective head squashes, suggesting involvement of the salivary gland barrier in these mosquitoes. Though there was no difference in the salivary gland positivity between these three species, the salivary gland area positivity was high in C, tritaeniorhynchus mosquitoes. Presence of virus antigen in t he ovaries and developing eggs of these three species on the third day sugg ests the possibility of transovarial transmission of virus even in the firs t gonotrophic cycle which may have epidemiological importance.