ISOLATION OF JAPANESE ENCEPHALITIS-VIRUS FROM CULEX ANNULIROSTRIS IN AUSTRALIA

Mosquitoes were collected using CO2 and octenol-baited light traps dur ing an outbreak of Japanese encephalitis (JE) on Badu island in the To rres Strait, Australia in April 1995. A total of 13,300 mosquitoes com prising 12 species were processed for virus isolation. Eight isolates of JE virus were obtained from Culex annulirostris, with a carriage ra te of 2.97:1,000; this mosquito also yielded one Sindbis virus isolate . A reverse transcriptase-polymerase chain reaction was used to sequen ce the JE viruses, which were compared with published sequences. The e ight isolates were 90% homologous with known JE strains but only 68% h omologous with other flaviviruses. Among the isolates, 99% homology wa s obtained, suggesting a common point of origin.