PREVALENCE OF WOLBACHIA IN WILD INSECTS AND ITS EFFECT ON MOSQUITO HOST

Abstract

Mosquito-borne diseases are a considerable threat to human and animal health. In order to limit their spread, several methods have been developed. However, the control of these diseases is still difficult and novel means of vector control are required as the threat becomes more eminent. The use of Wolbachia, an endosymbiotic alpha-proteobacterium, is one of the most exciting approaches used to limit virus transmission from mosquito to vertebrate. Wolbachia has been extensively studied in vector-control research because of its ability to induce cytoplasmic incompatibility. Wolbachia is thought to infect 20–70% of all arthropod species and several nematodes by being vertically transmitted through the maternal lineage. However, there is a debate concerning the percentage of insects infected with Wolbachia. Using PCR followed by DNA sequencing, our study shows that 20% of insects sampled from random geographic areas in Lebanon harbor Wolbachia. Previous studies showed that Wolbachia’s presence is responsible for pathogen blocking, while other studies showed that in its native host the protective effects of the endosymbiont are not detected. In this context, we aimed to analyze the effect of Wolbachia on Culex mosquito host immunity. We showed that Wolbachia enhances the survival of old mosquitoes in response to injection with gram-negative bacteria without affecting the survival of young mosquitoes. In summary, Wolbachia is present in 20% of our sampled insect population and its presence leads to an age-dependent immune modulatory role in Culex mosquito.