Diverse novel Wolbachia bacteria strains and genera-specific co-infections with Asaia bacteria in Culicine mosquitoes from ecologically diverse regions of Cameroon

Abstract

<ns4:p> <ns4:bold>Background:</ns4:bold> The endosymbiotic bacterium <ns4:italic>Wolbachia</ns4:italic> infects numerous species of insects and <ns4:italic>Wolbachia</ns4:italic> transinfection of <ns4:italic>Aedes</ns4:italic> mosquito species <ns4:italic/> is now being used for biocontrol programs as <ns4:italic>Wolbachia</ns4:italic> strains can both inhibit arboviruses and invade wild mosquito populations. The discovery of novel, resident <ns4:italic>Wolbachia</ns4:italic> strains in mosquito species warrants further investigation as potential candidate strains for biocontrol strategies. </ns4:p> <ns4:p> <ns4:bold>Methods:</ns4:bold> We obtained mosquito specimens from diverse Culicine mosquitoes from Cameroon including ecologically diverse locations in the Central and West Regions. <ns4:italic>Wolbachia</ns4:italic> prevalence rates were assessed in addition to the environmentally acquired bacterial species <ns4:italic>Asaia</ns4:italic> in major Culicine genera. PCR-based methods were also used with phylogenetic analysis to confirm identities of host mosquito species and <ns4:italic>Wolbachia</ns4:italic> strains were classified using multi-locus sequence typing (MLST). </ns4:p> <ns4:p> <ns4:bold>Results</ns4:bold> : We report high <ns4:italic>Wolbachia</ns4:italic> prevalence rates for Culicine species, including in a large cohort of <ns4:italic>Aedes africanus</ns4:italic> collected from west Cameroon in which 100% of mono-specific pools were infected. Furthermore, co-infections with <ns4:italic>Asaia</ns4:italic> bacteria were observed across multiple genera, demonstrating that these two bacteria can co-exist in wild mosquito populations. <ns4:italic>Wolbachia</ns4:italic> strain MLST and phylogenetic analysis <ns4:italic/> provided evidence for diverse <ns4:italic>Wolbachia</ns4:italic> strains in 13 different mosquito species across seven different genera. Full or partial MLST profiles were generated from resident <ns4:italic>Wolbachia</ns4:italic> strains in six <ns4:italic>Culex</ns4:italic> species ( <ns4:italic>quinquefasciatus</ns4:italic> , <ns4:italic>watti</ns4:italic> , <ns4:italic>cinerus, nigripalpus, perexiguus</ns4:italic> and <ns4:italic>rima),</ns4:italic> two <ns4:italic>Aedes</ns4:italic> species <ns4:italic>(africanus</ns4:italic> and <ns4:italic>denderensis)</ns4:italic> and in <ns4:italic>Mansonia uniformis, Catageiomyia argenteopunctata, Lutzia tigripes, Eretmapodites chrysogaster</ns4:italic> and <ns4:italic>Uranotaenia bilineata.</ns4:italic> </ns4:p> <ns4:p> <ns4:bold>Conclusions:</ns4:bold> Our study provides further evidence that <ns4:italic>Wolbachia</ns4:italic> is widespread within wild mosquito populations of diverse Culicine species and provides further candidate strains that could be investigated as future options for <ns4:italic>Wolbachia</ns4:italic> -based biocontrol to inhibit arbovirus transmission. </ns4:p>

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