ELISA for detecting dengue and Japanese encephalitis viral antigen in mosquitoes

Abstract

An indirect ELISA has been developed for detecting two viruses in triturated, experimentally infected mosquitoes: dengue (DEN) in Aedes aegypti (L.) and Ae. albopictus (Skuse) and Japanese encephalitis (JE) viral antigen in Culex tritaeniorhynchus Giles. DEN antigen from four strains of the virus, representing each of the four serotypes, and JE antigen were captured with a polyclonal anti-flavivirus IgG and detected with a monoclonal antibody (4G2) that reacts with all flaviviruses. Minimum viral titres detectable by the flavivirus antigen-capture ELISA, measured as multiples of the dose infecting 50% of mosquitoes (MID₅₀), were 10^{6 4}, 10^{4 5}, 10^{6 3}, 10^{6 9} and ≤ 10^6.9 MID₅₀/ml for DEN 1, DEN 2, DEN 3, DEN 4 and JE, respectively. Pools of up to 100 larvae or adults of Ae. aegypti and Ae. albopictus did not reduce the sensitivity of the ELISA to DEN 1, 2, 3 or 4. The results indicate that the antigen-capture ELISA could readily screen for DEN antigen in individual and pooled mosquitoes.