In South America, interest in tick-borne relapsing fever begun in the early 20th century and extended almost for 50 years. After this period, research on the disease vanished, opening a gap that has prevented a current approach with contemporary tools. Recently, its etiologic agent, the spirochete Borrelia venezuelensis, was re-isolated from its vector Ornithodoros rudis, in the Maranhão State (MA), northeastern Brazil. If we are to understand the eco-epidemiology of B. venezuelensis in this country, mainstream techniques are now required to develop studies. The objectives of the present project are (1) the standardization of in vitro culture of the isolated B. venezuelensis RMA01 stocked in our laboratory, (2) the sequencing of its genome, and (3) the design of a specific immunoblot for recognizing the circulation of B. venezuelensis antibodies in canine and human sera from MA. To this end, B. venezuelensis RMA01 will be re-activated in laboratory mice and cultivated in a modified version of the Barbour-Stoenner-Kelly (mBSK) medium. DNA extracted from mBSK-grown borreliae will be submitted to Next Generation Sequencing to obtain the complete sequences of its chromosome and large plasmid. Sequences of bipA gene will be transformed and expressed to obtain recombinant BipA protein (rBipA). Immunoblots composed by whole-cell lysates obtained from cultures and rBipA will be employed for testing anti-B. venezuelensis reactiveness of canine and human sera from MA. In its conjunct, the results of this study will represent the first efforts to understand the eco-epidemiology of tick-borne relapsing fever in Brazil. Serological tests will bring unprecedented data demonstrating whether domestic animals and/or humans are exposed to B. venezuelensis infection in MA. The genome of B. venezuelensis will provide accurate insights on the phylogenetic position of this spirochete, enabling to infer the evolutionary relationships with other species in the genus.
News published in Agência FAPESP Newsletter about the scholarship: