Screening of natural Wolbachia infection in mosquitoes (Diptera: Culicidae) from Cape Verde Islands

Abstract

BackgroundWolbachia pipientis is an endosymbiont bacteria that induce cytoplasmic incompatibility and inhibit arboviral replication in mosquitoes. This study aimed at estimating the prevalence and genetic diversity of Wolbachia in different mosquito (Diptera: Culicidae) species from Cape Verde. MethodsMosquitoes were collected in six islands of Cape Verde using dippers/pipettes, BG-sentinel(R) traps, CDC light traps, and dorsal aspirators. Samples were identified to species using morphological keys and PCR-based molecular assays. Wolbachia was detected by amplifying a fragment of the surface protein gene (wsp). Multilocus sequence typing (MLST) was performed with five housekeeping genes (coxA, gatB, ftsZ, hcpA and fbpA) and the wsp hypervariable region (HVR) for strain identification. Identification of wPip groups (wPip-I to wPip-V) was performed using PCR-RFLP assay on the ankyrin-domain gene pk1. ResultsNine mosquito species were collected, including the major vectors Aedes aegypti, Anopheles arabiensis, Culex pipiens s.s. and Culex quinquefasciatus. Wolbachia was detected in Cx. pipiens s.s. (100% prevalence), Cx. quinquefasciatus (98.3%), Cx. pipiens/quinquefasciatus hybrids (100%) and Culex tigripes (100%). Results from MLST and wsp hypervariable region typing showed that Wolbachia from Cx. pipiens s.l. belong to Sequence Type 9, wPip clade and supergroup B Wolbachia. Phylogenetic analyses indicate that Wolbachia isolated from Cx. tigripes belongs to Supergroup B but integrates a distinct clade from wPip with no attributed MLST profile. PCR-RFLP revealed wPip-II, wPip-III and wPip-IV groups in Culex pipiens s.l. wPip-IV was the dominant group, while wPip-II and wPip-III were restricted to Maio and Fogo islands, respectively. ConclusionOur study showed a high prevalence and diversity of Wolbachia in Cx pipiens s.l. from Cape Verde islands and, to the best of our knowledge, is the first to detect Wolbachia in Cx. tigripes, being represented in this species by a previously undescribed MLST Sequence Type.