title: Ectoparasite Infestations and Canine Infection by Rickettsiae and Ehrlichiae in a Semi-Arid Region of Northeastern Brazil.
abstract: This study investigated the prevalence of Rickettsia spp. and Ehrlichia canis infection in dogs and their ectoparasites from rural and urban areas of two municipalities, Petrolina and Juazeiro, within a semiarid region (Caatinga biome) of northeastern Brazil, by immunofluorescence assay (IFA) and polymerase chain reaction (PCR). Overall, 12.1% (61/504) and 23.0% (116/504) of canine plasma samples had antibodies reactive to Rickettsia spp. and E. canis. E. canis DNA was detected by PCR in 8.3% (42/504) of canine blood samples, whereas no blood sample was positive for Rickettsia spp. The infection by E. canis was determined by PCR in 4.9% (14/285) Rhipicephalus sanguineus sensu lato (s.l.) ticks and by Rickettsia felis in 1.1% (3/285) and 40.6% (74/182) ticks and fleas, respectively. Multivariate regression analyses revealed that canine seropositivity to Rickettsia spp. was associated statistically with the variables "to reside in Petrolina" and "presence of ectoparasites." Our results indicate that canine infection by E. canis might be endemic in the Caatinga biome as it is in other Brazilian biomes. Although no previous serosurvey for Rickettsia spp. has been conducted on dogs from the Caatinga biome, our values are much lower than the ones reported for rural dogs from other Brazilian biomes. These differences are likely related to the semiarid climate of the aatinga biome, which minimizes the exposure of rural dogs to Amblyomma spp. ticks, the most common vectors of Rickettsia spp. in Brazil. Considering that dogs are excellent sentinels for human exposure to Rickettsia spp., we can infer that the risks of human acquiring tick-borne rickettsiosis in the Caatinga region of the present study are low. The rickettsial infection rates in fleas and ticks were not related to canine seropositivity; i.e., areas with higher Rickettsia infection rates in fleas had the lowest canine seroreactivity to Rickettsia spp.
authors.affiliation: 1 Laboratório de Doenças Parasitárias, Universidade Federal do Vale do São Francisco , Petrolina, Pernambuco, Brazil .
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Araes-Santos
authors.affiliation: 2 Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo , São Paulo, São Paulo, Brazil .
authors.forename: Jonas
authors.initials: J
authors.lastname: Moraes-Filho
authors.affiliation: 3 Laboratório de Doenças Infecciosas, Universidade Federal do Vale do São Francisco , Petrolina, Pernambuco, Brazil .
authors.forename: Renata M
authors.initials: RM
authors.lastname: Peixoto
authors.affiliation: 2 Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo , São Paulo, São Paulo, Brazil .
authors.forename: Mariana G
authors.initials: MG
authors.lastname: Spolidorio
authors.affiliation: 4 Unidade Acadêmica de Medicina Veterinária, Universidade Federal de Campina Grande , Patos, Paraíba, Brazil .
authors.forename: Sérgio S
authors.initials: SS
authors.lastname: Azevedo
authors.affiliation: 3 Laboratório de Doenças Infecciosas, Universidade Federal do Vale do São Francisco , Petrolina, Pernambuco, Brazil .
authors.forename: Mateus M
authors.initials: MM
authors.lastname: Costa
authors.affiliation: 2 Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo , São Paulo, São Paulo, Brazil .
authors.forename: Marcelo B
authors.initials: MB
authors.lastname: Labruna
authors.affiliation: 1 Laboratório de Doenças Parasitárias, Universidade Federal do Vale do São Francisco , Petrolina, Pernambuco, Brazil .
authors.forename: Mauricio C
authors.initials: MC
authors.lastname: Horta
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001179:Arthropod Vectors / Q000382:microbiology; D001938:Brazil / Q000453:epidemiology; D004283:Dog Diseases / Q000453:epidemiology* / Q000382:microbiology; D004285:Dogs; D041061:Ehrlichia canis / Q000276:immunology / Q000302:isolation & purification*; D016873:Ehrlichiosis / Q000453:epidemiology / Q000662:veterinary*; D058267:Flea Infestations / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D048508:Rhipicephalus sanguineus / Q000382:microbiology; D012281:Rickettsia / Q000276:immunology / Q000302:isolation & purification*; D012282:Rickettsia Infections / Q000453:epidemiology* / Q000382:microbiology / Q000662:veterinary; D005423:Siphonaptera / Q000382:microbiology
chemical_list: D000907:Antibodies, Bacterial
keywords: Caatinga; Dogs; Ehrlichia canis; Fleas; Rickettsia; Ticks