Molecular Ecology of Endosymbiotic Bacteria in Arthropod Vectors in Saudi Arabia

Abstract

Abstract Pathogens affecting humans and other animals, including viruses, bacteria, nematodes, and protozoa, can be transmitted by rodent ectoparasites. These ectoparasites harbour various endosymbiotic microorganisms that influence their physiology and survival. Despite the known pathogenic impacts of these vectors, limited research exists in many regions on the molecular basis of vector-endosymbiont interactions, including for Wolbachia and Rickettsia species. This study investigates the ecology of symbionts and the diversity within arthropods collected from the Al-Baha and 'Asir regions of Saudi Arabia. The objective was to characterise the endosymbiotic bacteria in these arthropods using multi-locus sequence typing and phylogenetic analysis and determine the correlation between endobacterial sequence types and co-infection rates. Molecular identification on collected flea and tick samples was performed targeting the cytochrome oxidase subunit 1 (COI) gene for ectoparasite species identification, the16S rRNA gene for Wolbachia, and the sca4 and gltA genes for Rickettsia identification, respectively. Results revealed the presence of multiple Wolbachia strains and high sequence similarity to known Rickettsia species, including Rickettsia conorii, which is associated with Mediterranean spotted fever. The phylogenetic analysis of flea Wolbachia identified potentially novel strains and possibly novel supergroups. These findings contribute to a deeper understanding of the symbiotic and possible pathogenic landscape of ectoparasites in Saudi Arabia. By mapping the diversity of these microorganisms, this study underscores the complex interactions between ectoparasites and their symbionts and the need for further research in overlooked regions.