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

Background: Dengue viruses (DENV) can be transmitted vertically in Aedes aegpti (Ae. aegypti) mosquitoes. Whether the endosymbiont Wolbachia ( w Mel 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 w Mel 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 w Mel infected Ae. aegypti , the MLE was 0%. Conclusions: The results reinforce that vertical transmission is a rare event in wild-type mosquitoes and that w Mel infection reduces the probability of vertical transmission even further.