title: Ecology of a tick-borne spotted fever in southern Brazil.
abstract: Rio Grande do Sul is the southernmost state of Brazil, bordering Uruguay. Clinical cases of spotted fever group (SFG) rickettsiosis were recently reported in Rio Grande do Sul. None of these cases was lethal, and all were confirmed by seroconversion to R. rickettsii antigens. Because serological cross-reactions are well known to occur between different SFG agents, the SFG agent responsible for the clinical cases remains unknown in Rio Grande do Sul, where no rickettsial agent is known to infect ticks. During 2013-2014, ticks and blood sera samples were collected from domestic dogs and wild small mammals, and from the vegetation in a SFG-endemic area of Rio Grande do Sul. Dogs were infested by Amblyomma ovale adult ticks, whereas small mammals were infested by immature stages of A. ovale, Ixodes loricatus, and adults of I. loricatus. Ticks collected on vegetation were adults of A. ovale, and immature stages of A. ovale, Amblyomma dubitatum, and Amblyomma longirostre. Three Rickettsia species were detected: Rickettsia bellii in I. loricatus, Rickettsia amblyommii in A. longirostre, and a Rickettsia parkeri-like agent (Rickettsia sp. strain Atlantic rainforest) in A. ovale. Seroreactivity to SFG antigens were detected in 19.7 % (27/137) canine and 37.5 % (15/40) small mammal sera, with highest titers to R. parkeri. Results indicate that the R. parkeri-like agent, strain Atlantic rainforest, is circulating between A. ovale ticks, dogs and small mammals in the study area, suggesting that this SFG pathogen could be one of the etiological agents of SFG clinical cases in Rio Grande do Sul.
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Orlando Marques de Paiva, 87, Cidade Universitária, São Paulo, SP, 05508-270, Brazil.
authors.forename: Felipe S
authors.initials: FS
authors.lastname: Krawczak
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Orlando Marques de Paiva, 87, Cidade Universitária, São Paulo, SP, 05508-270, Brazil.
authors.forename: Lina C
authors.initials: LC
authors.lastname: Binder
authors.affiliation: Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
authors.forename: Caroline S
authors.initials: CS
authors.lastname: Oliveira
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Orlando Marques de Paiva, 87, Cidade Universitária, São Paulo, SP, 05508-270, Brazil.
authors.forename: Francisco B
authors.initials: FB
authors.lastname: Costa
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Orlando Marques de Paiva, 87, Cidade Universitária, São Paulo, SP, 05508-270, Brazil.|Mestrado em Medicina Veterinária e Bem Estar Animal, Universidade de Santo Amaro, São Paulo, SP, Brazil.
authors.forename: Jonas
authors.initials: J
authors.lastname: Moraes-Filho
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Orlando Marques de Paiva, 87, Cidade Universitária, São Paulo, SP, 05508-270, Brazil.
authors.forename: Thiago F
authors.initials: TF
authors.lastname: Martins
authors.affiliation: Departamento de Biologia, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
authors.forename: Jonas
authors.initials: J
authors.lastname: Sponchiado
authors.affiliation: Departamento de Ecologia, Universidade Federal do Mato Grosso do Sul, Campo Grande, MS, Brazil.
authors.forename: Geruza L
authors.initials: GL
authors.lastname: Melo
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Orlando Marques de Paiva, 87, Cidade Universitária, São Paulo, SP, 05508-270, Brazil.
authors.forename: Fábio
authors.initials: F
authors.lastname: Gregori
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Orlando Marques de Paiva, 87, Cidade Universitária, São Paulo, SP, 05508-270, Brazil.
authors.forename: Gina
authors.initials: G
authors.lastname: Polo
authors.affiliation: Secretaria de Vigilância em Saúde, Ministério da Saúde, Brasília, DF, Brazil.
authors.forename: Stefan V
authors.initials: SV
authors.lastname: Oliveira
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Orlando Marques de Paiva, 87, Cidade Universitária, São Paulo, SP, 05508-270, Brazil. labruna@usp.br.
authors.forename: Marcelo B
authors.initials: MB
authors.lastname: Labruna
mesh_terms: D000818:Animals; D000829:Animals, Domestic; D000835:Animals, Wild; D001938:Brazil / Q000453:epidemiology; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D026863:Ixodidae / Q000254:growth & development / Q000502:physiology*; D007814:Larva / Q000254:growth & development / Q000502:physiology; D008297:Male; D009758:Nymph / Q000254:growth & development / Q000502:physiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012281:Rickettsia / Q000235:genetics / Q000302:isolation & purification*; D012282:Rickettsia Infections / Q000453:epidemiology* / Q000382:microbiology; D017422:Sequence Analysis, DNA; D013984:Tick Infestations / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: Amblyomma longirostre; Amblyomma ovale; Ixodes loricatus; Rickettsia amblyommii; Rickettsia bellii; Rickettsia sp. strain Atlantic rainforest