COMPARATIVE ORAL SUSCEPTIBILITY OF DENGUE VECTOR MOSQUITOES FROM JAPAN AND SOUTHEAST ASIA TO TWO DENGUE-1 VIRUS STRAINS

Five geographic strains of Aedes albopictus from Japan and Southeast Asia and three strains of Aedes aegypti from Indonesia and Pakistan were compared for their susceptibility to oral infection with the human virus, dengue-1 Mochizuki strain (isolated in 1943, Japan) and A88 strain (isolated in 1988, Indonesia). Female mosquitoes, aged 3-4 days, were infected with a virus-erythrocyte-sucrose suspension. After 14 days of incubation at 25-30°C, viral infection in mesenteron (midgut) or in head-thorax (salivary gland) of each individual mosquito was identified by the reverse transcriptase-polymerase chain reaction (RT-PCR) amplification of dengue-1 virus envelope gene. Although the results of susceptibility varied in some extent in different strains of mosquitoes and viral strains, the oral susceptibility to both dengue-1 virus strains was not significantly different among dengue vector mosquitoes from Japan and Southeast Asia.