Abstract
Dengue cases in Bangladesh have surged in recent years. The existing insecticide-based control program, implemented in parts of the country, is challenged by issues of insufficient household coverage and high levels of insecticide resistance in the primary dengue virus (DENV) vector, Aedes aegypti. A more sustainable, effective alternative could be the implementation of a Wolbachia-mediated disease management strategy. Infecting mosquitoes with Wolbachia can change their reproductive compatibility and their ability to transmit DENV. These new phenotypes can be exploited to suppress or replace wild-type Ae. aegypti populations. Such strategies require the development of well-characterised Wolbachia-infected strains with biological characteristics that are comparable with local mosquitoes. We created and characterised a Wolbachia-infected Ae. aegypti strain with a Dhaka wild-type genetic background, and compared its reproductive compatibility, maternal inheritance, fitness, and virus-blocking ability to the parental strains (Dhaka wild-type and wAlbB2-F4). The new Ae. aegypti strain wAlbB2-Dhaka demonstrated complete cytoplasmic incompatibility with the wild-type strain and complete maternal transmission, retaining levels of pyrethroid resistance of the Dhaka wild-type (70% survival to 10 times the dose of permethrin expected to kill susceptible mosquitoes). No significant fitness costs were detected during laboratory comparisons of fecundity, fertility, survival, mating competitiveness, or desiccation tolerance. Compared to the wild-type strain, wAlbB2-Dhaka mosquitoes had a significantly reduced number of DENV genome copies in the bodies (44.4%, p = 0.0034); two-fold reduction in dissemination to legs and wings (47.6%, p < 0.0001); and >13-fold reduction of DENV in saliva expectorates (proxy of transmission potential) (92.7%, p < 0.0001) 14 days after ingesting dengue-infected blood. Our work indicates that the wAlbB2-Dhaka strain could be used for Ae. aegypti suppression or replacement strategies for dengue management in Bangladesh.
Competing Interest Statement
The authors have declared no competing interest.