In Brazil, few people know that in the Tupi language bats are called ‘andirá’, ‘guandira’, or ‘guandiruçu’. The lack of knowledge about these animals is not restricted to these names but to the diversity of species, their biological complexity and their ecological importance. Bats (Chiroptera) are among the most diverse and geographically dispersed mammals. They are of great importance to the ecosystem, as pollinators, seed dispersers, and controllers of pests, and they are also hosts of several ectoparasites. Ectoparasites include a variety of arthropods, such as ticks (Ixodida), mites (Mesostigmata, Sarcoptiformes, and Trombidiformes), lice (Anoplura), fleas (Siphonaptera) and flies (Diptera), and their diet includes tissues and blood or other bodily fluids of bats. Bats are reservoirs of various disease-causing agents, many of them pathogenic to humans, such as bacteria of the genera Borrelia, Bartonella, Coxiella, Orientia and Rickettsia, as well as protozoa (among the most important, Leishmania spp. and Trypanosoma cruzi), viruses (the most important being rabies and Ebola) and fungi (Histoplasma and Crytococcus). This study was carried out in Monte Negro, Rondônia, and the occurrence of ectoparasites in bats was evaluated, as well as the bacteria of medical importance carried by these ectoparasites. Through a total of 69 nocturnal captures, 217 specimens of chiropterans representing 23 species and six families were sampled. A total of 592 specimens of ectoparasites were collected from the bats. Bacteria of the genus Bartonella were found in two species of bat flies (Trichobius joblingi and Strebla mirabilis). We report for the first time in Rondônia the argasid tick Ornithodoros hasei and its infection by a bacterium of the spotted fever group Candidatus Rickettsia wissemanii.
