Rickettsia amblyommatis infecting Amblyomma pseudoconcolor in area of new focus of spotted fever in northeast Brazil.

In Brazil, active infections of Rickettsia spp. is confirmed in all regions, involving various species of ticks. During investigation of a new focus of Spotted Fever (SF) incidence in the state of Pernambuco, northeastern Brazil, tick species Rhipicephalus sanguineus sensu lato (Latreille), and Amblyomma pseudoconcolor were collected from one Canis familiaris and four Euphractus sexcinctus, respectively, and analized for the presence of rickettsial genes. Ten A. pseudoconcolor ticks (90.9%) were found to be infected with Rickettsia, whereas no evidence of Rickettsia spp. was found in R. sanguineus s. l. Genetic analysis based of five rickettsial genes showed that the detected strain is most closely related to Rickettsia amblyommatis (formerly Candidatus Rickettsia amblyommii). R. amblyommatis was, for the first time, detected in Amblyomma pseudoconcolor and the results pointed to this tick like a potential vector in the enzootic cycle of R. amblyommatis in a typical semiarid Brazilian savannah region. In conclusion, despite the need for further studies to confirm if R. amblyommatis was responsible for the observed case in the state of Pernambuco, the presence of this bacterium during an SF focussed investigation should be a major concern in terms of public health due the capacity of SF for rapid and extensive dispersion within Brazilian territory.

Fatal case of spotted fever in a patient from Northeastern Brazil.

Spotted fevers are diseases caused by bacterial agents belonging to the spotted-fever (SF) group of the genus Rickettsia. The first documented case of SF in Pernambuco State, Northeast Brazil, was reported here. Also, it is the first case described of fatal SF in Northeast region of Brazil. The patient was a resident of Arcoverde municipality and the probable site of infection lies in Sertania municipality, both in Pernambuco State, a semi-arid region of Brazil. The patient had not visited other areas where SF is endemic. The patient showed clinical manifestations and epidemiological exposure compatible with SF, and the infection was confirmed by molecular biology techniques.