Natural <i>Wolbachia</i> infections are common in the major malaria vectors in Central Africa

Abstract

During the last decade, the endosymbiont bacterium <i>Wolbachia</i> has emerged as a biological tool for vector disease control. However, for long time, it was believed that <i>Wolbachia</i> was absent in natural populations of <i>Anopheles</i>. The recent discovery that species within the <i>Anopheles gambiae</i> complex host <i>Wolbachia</i> in natural conditions has opened new opportunities for malaria control research in Africa. Here, we investigated the prevalence and diversity of <i>Wolbachia</i> infection in 25 African <i>Anopheles</i> species in Gabon (Central Africa). Our results revealed the presence of <i>Wolbachia</i> 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 <i>Wolbachia</i> strains that infect <i>Anopheles</i>. Co-evolutionary analysis unveiled patterns of <i>Wolbachia</i> transmission within some <i>Anopheles</i> species, suggesting that past independent acquisition events were followed by co-cladogenesis. The large diversity of <i>Wolbachia</i> strains that infect natural populations of <i>Anopheles</i> offers a promising opportunity to select suitable phenotypes for suppressing <i>Plasmodium</i> transmission and/or manipulating <i>Anopheles</i> reproduction, which in turn could be used to reduce the malaria burden in Africa.