Detecção de Wolbachia em mosquitos (Diptera: Culicidae) no estado do Maranhão, Brasil

Abstract

It is estimated that about 66% of all known arthropod species are infected with Wolbachia. This endosymbiont has been widely studied due to its high natural diversity and mainly due to its ability to reduce infection by pathogens that cause diseases such as Dengue, Zika, Chikungunya, Yellow Fever and Malaria, transmitted by mosquitoes. Despite this, there is little information about the dispersion of Wolbachia in natural environments in Brazil. Such knowledge is important, as it allows estimating the extent of natural infection in hosts and the use of certain strains in the biological control of vector mosquitoes. The aim of this study was to evaluate the rate of natural infection by Wolbachia in different species of Culicidae in representative areas of the State of Maranhão. Mosquitoes were collected with CDC-HP traps, ovitraps, sapucaias and Shannon's tent in the municipalities of São Luís, São José de Ribamar, Chapadinha, Vitória do Mearim, Godofredo Viana and Pastos Bons. Insect DNA was extracted and the Wsp gene amplified by Polymerase Chain Reaction. In total, 448 individuals of 18 species and 7 genera of Culicidae were analyzed. Mosquitoes in Maranhão are infected with Wolbachia, with high frequencies of infection for physiologically more permissive species such as Ae. albopictus and Cx. quinquefasciatus. Overall, the average infection rate was 17%, with variation between species ranging from 4% to 80%. Wolbachia DNA was found in 6 species: Ae. albopictus, Ae. scapulari, Cx. quinquefasciatus, Cq. juxtamansonia and Cq. Venezuelensis. In addition to mosquitoes of the Anopheles (Nys.) spp and Cx. (Mel.) spp. complexes, this is the first record of Ae. scapulari, Cx. juxtamansonia, Cq. Venezuelensis infected with Wolbachia in the World. Species Ae. albopictus and Cx. quinquefasciatus for having a high prevalence and are the most suitable for studies aiming to assess the influence of Wolbachia on the life cycle and evolutionary processes of speciation. The average positivity in the genera Aedes (27%), Anopheles (2.5%), Culex (38%) and Coquillettidia (23%) allowed us to infer that Aedes, Culex and Coquillettidia have a high capacity to maintain fixation and endosymbiosis relationships in natural environments. Despite this, the infection was not detected in mosquitoes of the species Ae. Aegypti. Despite the low rate of infection in the genus Anopheles, here we detected infection in Anophelines of the subgenus Nyssorhynchus. Like Anopheles, Cellia and Lophopodomyia, Nyssorhynchus is physiologically permissive to support Wolbachia infection.