Pequenos mamíferos não voadores no vale do rio Paranaíba, Brasil: manutenção de leptospiras patogênicas e carrapatos

Abstract

The Paranaiba’s river is located predominantly without Cerrado biome, with some spots of Atlantic Forest. Small mammals are models and no study of ticks and circulation of pathogens, even in environments with different degrees of degradation. The present study describes the different species of small non-flying mammals in the Paranaíba River valley, and their identification as renal carriers of pathogenic leptospiras. Investigates the role of small non-flying wild and synanthropic mammals in the ecology of leptospirosis in a rural property in the southeastern region of the state of Goiás. In addition, evaluates the role of these animals as hosts for ticks in Cerrado areas, in the Paranaíba river valley. Seventy-two small non-flying mammals were captured from three species of marsupials and eight rodent species. Of these 72, 24 (33.33%) were positive for lipL32 gene PCR and only one specimen, Gracilinanus agilis, was MAT reagent for serovar Australis. Among the marsupials, 14 (32.56%) were PCR positive, and 10 rodent specimens (34.48%) were diagnosed as renal carriers by the same technique. Cattle owned in the southeastern region of the state of Goiás reacted mainly to strains belonging to the serogroup Icterohaemorrhagiae, maintained by small mammals. Of the total of small mammals captured, ticks infested only 14 animals, corresponding to the genera Nectomys, Cerradomys, Oecomys, Necromys and Gracilinanus. The tick richness was at least 04 species in the Alto Paranaíba (Ixodes sp., Ornithodoros sp., Amblyomma dubitatum, Amblyomma sculptum) in addition to Amblyomma sp. 02 in the Middle Paranaíba (Ornithodoros sp. and Amblyomma dubitatum), and Amblyomma sp. and only 01 in the Low Paranaíba (Ornithodoros sp.). Small non-flying mammals play a role of pathogenic leptospires carriers in the Paranaíba river valley. This is the first report of PCR identification of Gracilinanus agilis, Calomys sp., Hylaeamys megacephala and Oecomys bicolor as renal carriers of pathogenic leptospires. Small mammals play a relevant role in the ecology of leptospirosis in rural dairy farms, favoring the infection of cattle. Ticks of the genus Ornithodoros sp. were found parasitizing only the didelid Gracilinanus sp. The Ambliomma dubitatum tick was the most frequent occurrence in small mammals in the Paranaíba river valley, and this seems to be the first record of this species in Nectomys sp. in the Cerrado biome. As well as the first, record of Ixodes loricatus parasitizing Cerradomys sp., and the first record of Ixodes loricatus in Rhipidomys sp. in Brazil.