Résumé
During the last decade, the endosymbiont bacterium Wolbachia has emerged
as a biological tool for vector disease control. However, for long time,
it was believed that Wolbachia was absent in natural populations of
Anopheles. The recent discovery that species within the Anopheles gambiae
complex host Wolbachia in natural conditions has opened new opportunities
for malaria control research in Africa. Here, we investigated the
prevalence and diversity of Wolbachia infection in 25 African Anopheles
species in Gabon (Central Africa). Our results revealed the presence of
Wolbachia in 16 of these species, including the major malaria vectors in
this area. The infection prevalence varied greatly among species,
confirming that sample size is a key factor to detect the infection.
Moreover, our sequencing and phylogenetic analyses showed the important
diversity of Wolbachia strains that infect Anopheles. Co-evolutionary
analysis unveiled patterns of Wolbachia transmission within some Anopheles
species, suggesting that past independent acquisition events were followed
by co-cladogenesis. The large diversity of Wolbachia strains that infect
natural populations of Anopheles offers a promising opportunity to select
suitable phenotypes for suppressing Plasmodium transmission and/or
manipulating Anopheles reproduction, which in turn could be used to reduce
the malaria burden in Africa.