Natural transovarial dengue virus infection rate in both sexes of dark and pale forms of Aedes aegypti from an urban area of Bangkok, Thailand.

Transovarial dengue virus infection status of two forms of adult Aedes aegypti (dark or Ae. aegypti type form and pale or form queenslandensis), reared from field-collected larval and pupal stages, was determined by one-step RT-PCR and dengue viral serotype by nested-PCR. Natural transovarial transmission (TOT) of dengue virus was detected in the two Ae. aegypti forms, and in both adult males and females. Male Ae. aegypti had a higher rate of TOT dengue virus infection than female. The overall minimum infection rate among the male and female populations was 19.5 and 12.3 per 1,000 mosquitoes, respectively. All four dengue serotypes were detected in mosquito samples, with DEN-4 being the predominant serotype. Thus, both male and female Ae. aegypti have influences on the epidemiology of dengue virus transmission.