ABSTRACT
A 12-year old mixed breed neutered bitch from Misiones, Argentina, was presented with a history of fever and epistaxis. Blood, bone marrow, and lymph node samples were collected for hematology and cytology. Mild regenerative anemia was recorded and large, round, poorly stained piroplasms (>2.5 µm) were found within erythrocytes in blood and lymph node smears. Nested PCR-RFLP on blood and bone marrow samples was positive for piroplasm DNA. The 18S rRNA gene of piroplasms was targeted. A restriction pattern of a previously unreported piroplasm was observed. The PCR product was sequenced, and the sequence obtained had 99% identity with the Rangelia vitalii sequences from Brazil when compared by BLAST analysis. Further characterization of the detected piroplasm consisted of nearly full-length sequencing (1668 bp) of the 18S rRNA gene of this organism. Those sequences were deposited in GenBank. A phylogenetic analysis indicated that they clustered together with R. vitalii from Brazil but separately from large Babesia species of dogs such as Babesia canis, and from species of Theileria of dogs as well. This is the first report of R. vitalii infection in Argentina, and the first case of canine rangeliosis diagnosed outside Brazil.
Subject(s)
Dog Diseases/parasitology , Piroplasmida/isolation & purification , Protozoan Infections, Animal/parasitology , Animals , Argentina/epidemiology , Base Sequence , Dog Diseases/epidemiology , Dogs , Female , Molecular Sequence Data , Phylogeny , Piroplasmida/classification , Piroplasmida/genetics , Protozoan Infections, Animal/epidemiology , RNA, Ribosomal, 18S/chemistry , RNA, Ribosomal, 18S/genetics , RNA, Ribosomal, 18S/metabolismABSTRACT
Bacteria belonging to the Anaplasmataceae family are vector transmitted agents that affect a variety of vertebrate hosts including the tick-borne pathogens Ehrlichia canis and Anaplasma platys, which cause canine monocytic ehrlichiosis and cyclic thrombocytopenia, respectively. These two infections, typically reported from tropical and sub-tropical regions, have not been previously reported in dogs from Argentina. A total of 86 blood samples from dogs with suspected rickettsial disease and 28 non-suspected dogs were studied. Analysis included evaluation of hematological findings, PCR for Ehrlichia and Anaplasma species and sequencing of the positive PCR products. E. canis was detected in the blood of six dogs and A. platys in eighteen. All the dogs categorized as non-suspected were negative by PCR. Co-infection with Hepatozoon canis and Babesia vogeli was documented. This first report of E. canis and A. platys infections in dogs from Argentina indicates that these tick-borne infections have a considerably broader range than previously recognized in South America.
