Natural Wolbachia infections are common in the major malaria vectors in Central Africa

Abstract

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.

Complete mitogenome sequence of Anopheles coustani from São Tomé island

“…The 622 bp long COII fragment spanning Mt:3054-3675 was 99.7% identical to the published A. coustani COII sequence from Gabon (Ayala et al. 2019 ). In addition, we sequenced the internal transcribed spacer 2 (ITS2; GenBank: MT791041) region of nuclear ribosomal DNA which was 99.64% identical to the published A. coustani from Guinea (Cansado-Utrilla et al.…”

A bioinformatics approach to identifyingWolbachiainfections in arthropods

“…The strain identified here clearly belongs to supergroup B, and is related to strains infecting Hymenoptera and Lepidoptera, rather than fleas (Siphonaptera) like the previously identified supergroup A strain. In addition, other recent surveys have found evidence of diverse Wolbachia strains, including supergroup B strains, within the A. gambiae species complex ( Ayala et al, 2018 ; Jeffries et al, 2018 ). Combined, these results suggest that the diversity of Wolbachia infections in Anopheles may be currently underappreciated.…”

Genomic and microscopic evidence of stable high density and maternally inherited Wolbachia infections in Anopheles mosquitoes

“…In addition, the inability to find Wolbachia reads using microbiome sequencing in nested-PCR positive individuals raises concerns about the validity of this assay, which has been commonly used to report detection of Wolbachia infections in Anopheles mosquitoes [16][17][18][19][20][21] . A recent study using 16S rRNA gene sequencing of nested PCR positive An.…”

“…While the standing dogma in the Wolbachia field for many years was that Anopheles mosquitoes were impervious to Wolbachia infection 13,14 , there have been numerous recent reports of natural infections in a range of Anopheles species [15][16][17][18][19][20][21][22] . However, the majority of these studies found low density, low prevalence Wolbachia infections in diverse Anopheles species.…”