title: Genetic diversity of Ehrlichia canis strains from naturally infected dogs in Rio de Janeiro, Brazil.
abstract: The aim of this study was to characterize Ehrlichia canis strains from naturally infected dogs in Rio de Janeiro, Brazil. In addition, all the clinical and hematological findings observed in these dogs were reported. PCR targeting the 16S rRNA gene was used for diagnostic purposes, and the TRP19 and TRP36 genes were sequenced to evaluate the genetic diversity. Fifteen samples were positive for E. canis. The polymerase chain reaction for the TRP19 gene resulted in 11 amplicons (11/15), which were cloned into the pGEM-T easy vector for sequencing. The complete sequence of TRP19 gene was compared to those in the GenBank, revealing high identicalness. Phylogenetic analysis on the TRP36 gene sequences demonstrated two distinct strains from two dogs, named 56C and 70C. The 56C strain was grouped with the strain Cuiaba 16, which is a hybrid strain formed by Brazilian and US genogroups; and the 70C strain was grouped with other strains of the US genogroup, thus suggesting that there are at least two genogroups of E. canis in Rio de Janeiro (US and Brazilian). Those animals, in which the 70C and 56C strains were isolated, showed distinct clinical and hematological manifestations of the disease. The appearance of different genotypes may express new phenotypes, thus resulting in different forms of presentation of the disease and making its diagnosis more complex.
authors.affiliation: Departamento de Patologia e Clínica Veterinária, Faculdade de Veterinária, Universidade Federal Fluminense ? UFF, Niterói, RJ, Brasil.
authors.forename: Renata Fernandes
authors.initials: RF
authors.lastname: Ferreira
authors.affiliation: Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense ? UFF, Niterói, RJ, Brasil.
authors.forename: Aloysio de Mello Figueiredo
authors.initials: Ade M
authors.lastname: Cerqueira
authors.affiliation: Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense ? UFF, Niterói, RJ, Brasil.
authors.forename: Tatiana Xavier de
authors.initials: TX
authors.lastname: Castro
authors.affiliation: Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro ? UFRJ, Rio de Janeiro, RJ, Brasil.
authors.forename: Eliane de Oliveira
authors.initials: Ede O
authors.lastname: Ferreira
authors.affiliation: Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense ? UFF, Niterói, RJ, Brasil.
authors.forename: Felipe Piedade Gonçalves
authors.initials: FP
authors.lastname: Neves
authors.affiliation: Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense ? UFF, Niterói, RJ, Brasil.
authors.forename: André Victor
authors.initials: AV
authors.lastname: Barbosa
authors.affiliation: Departamento de Patologia e Clínica Veterinária, Faculdade de Veterinária, Universidade Federal Fluminense ? UFF, Niterói, RJ, Brasil.
authors.forename: Daniel de Barros
authors.initials: Dde B
authors.lastname: Macieira
authors.affiliation: Departamento de Patologia e Clínica Veterinária, Faculdade de Veterinária, Universidade Federal Fluminense ? UFF, Niterói, RJ, Brasil.
authors.forename: Nádia Regina Pereira
authors.initials: NR
authors.lastname: Almosny
mesh_terms: D000818:Animals; D001938:Brazil; D004285:Dogs / Q000382:microbiology*; D041061:Ehrlichia canis / Q000235:genetics* / Q000302:isolation & purification; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D008297:Male; D016133:Polymerase Chain Reaction