Wolbachia wMel-mediated effects on dengue virus vertical transmission from Aedes aegypti to their offspring

Abstract

Background: Dengue viruses (DENV) can be transmitted vertically in Aedes aegpti (Ae. aegypti) mosquitoes. Whether the endosymbiont Wolbachia (wMel strain) can reduce the incidence of vertical transmission of DENV from infected females to their offspring is not well understood.Methods We used intrathoracic injection (IT) of DENV-1 to estimate the rate of vertical transmission of the virus in a laboratory colony of Vietnamese Ae. aegypti, both with and without wMel infection. We applied the Maximum Likelihood Estimator (MLE) to calculate the infection rate of individual mosquitoes in their offspring.Results In 6,047 F1 Vietnamese wild-type Ae. aegypti, the MLE of DENV-1 infection was 1.49% (95%CI = 0.73–2.74). In 5,500 wMel infected Ae. aegypti, the MLE was 0%.Conclusions The results reinforce that vertical transmission is a rare event in wild-type mosquitoes and that wMel infection reduces the probability of vertical transmission even further.