Systematic Review of Wolbachia Symbiont Detection in Mosquitoes: An Entangled Topic about Methodological Power and True Symbiosis

Abstract

Wolbachia is an endosymbiotic bacterium that naturally infects several arthropods and nematode species. Wolbachia gained particular attention due to its impact on their host fitness and the capacity of specific Wolbachia strains in reducing pathogen vector and agricultural pest populations and pathogens transmission. Despite the success of mosquito/pathogen control programs using Wolbachia-infected mosquito release, little is known about the abundance and distribution of Wolbachia in most mosquito species, a crucial knowledge for planning and deployment of mosquito control programs and that can further improve our basic biology understanding of Wolbachia and host relationships. In this systematic review, Wolbachia was detected in only 30% of the mosquito species investigated. Fourteen percent of the species were considered positive by some studies and negative by others in different geographical regions, suggesting a variable infection rate and/or limitations of the Wolbachia detection methods employed. Eighty-three percent of the studies screened Wolbachia with only one technique. Our findings highlight that the assessment of Wolbachia using a single approach limited the inference of true Wolbachia infection in most of the studied species and that researchers should carefully choose complementary methodologies and consider different Wolbachia-mosquito population dynamics that may be a source of bias to ascertain the correct infectious status of the host species.

Rediscovering the mosquito fauna (Diptera: Culicidae) of Estonia: an annotated checklist with distribution maps and DNA evidence

“…Also, Cx. pipiens specimens in Estonia were found to be infected with the intercellular symbiont Wolbachia pipientis, which agrees with the published literature (Bergman & Hesson 2021;Inácio da Silva et al 2021). No attempts were made to identify the "molestus" biotype of Cx.…”

Cytoplasmic incompatibility in the semivoltine longicorn beetle Acalolepta fraudatrix (Coleoptera: Cerambycidae) double infected with Wolbachia

“…There are many reviews summarizing the state of knowledge about Wolbachia infection groups of insects, including Heteropteran bugs [16], springtails [17], ants [18] wasps [19], butterflies [20], and mosquitoes [21]. Despite this progress in studies on Wolbachia infection in insects, knowledge about its interaction with species in the order Coleoptera is still sparse [22].…”

Wolbachia 16S rRNA haplotypes detected in wild Anopheles stephensi in eastern Ethiopia

“…This could increase the effectiveness of the PCR assays, as they would amplify actively expressed genes rather than the scenarios below. A recent systematic review discussed the different scenarios in which Wolbachia could be detected in a mosquito [ 23 ]. The authors pointed out that under scenarios such as a mosquito with an endogenized gene from Wolbachia , environmental contamination, or a mosquito infected with a nematode infected with Wolbachia , Wolbachia would be detectable by PCR assay, nested PCR assay, qPCR, and possibly MLST.…”

“…Gomes et al were only able to amplify three out of five genes, and Jeffries et al were unable to amplify any MLST genes in multiple sample groups [ 18 , 20 ]. This may indicate that environmental contamination is present or that divergence among these genes has emerged, precluding the use of the standard MLST primer set [ 18 , 22 , 23 ].…”