Brazilian spotted fever in urban environments: control strategies and measures for risk reduction

Abstract Introduction Brazilian spotted fever (BSF), caused by Rickettsia rickettsii , is a disease transmitted by ticks that has a high fatality rate. The process of urbanization has been observed in recent decades. It is recommended that the management of capybaras ( Hydrochoerus hydrochaeris ) be implemented in order to reduce the risk of population contagion. In a municipal park of Divinópolis-MG, a city with autochthonous cases and deaths by BSF, the following procedures were proposed with the aim of controlling BSF: sterilization of groups of capybaras, monitoring of their home range and serological survey. Material and methods Eight areas were selected and divided into two categories: areas with human access and areas with no human access. Over the course of a year, ten collections of ticks were conducted. The species of the collected specimens were identified, and the specimens were tested for SFGR ( gltA and ompA genes ) through real-time polymerase chain reaction (qPCR). The capybaras were sterilized and monitored via the use of GPS collars. The blood and ticks from the sterilized animals were subjected to testing through the use of an indirect immunofluorescence assay (IFA) and qPCR, respectively. Results A total of 7841 ticks were collected, the majority of which were identified as Amblyomma sculptum . Areas with restricted human access exhibited a significantly higher prevalence of ticks ( P < 0.001) compared to areas with more accessible human traffic. A total of ten capybaras were divided into two groups with constant home ranges along the river and underwent sterilization. The gltA gene was identified in the three ticks collected from the environment, while the Rickettsia sp. gene was found in the ticks collected from six capybaras (two from group 1 and four from group 2). The serological analysis yielded positive results in four animals from Group 1 (IFA). Conclusion In the area under study, areas with easy human access have a lower tick population than areas without human use. The capybaras' territory is stable, irrespective of the occurrence of river floods. The samples collected from the capybaras were more effective for rickettsial detection than the ticks collected in the field. It is essential to conduct continuous monitoring of the animals for effective BSF control.