Rangelia vitalii in naturally infected dogs in southern Brazil: clinical classification of the disease into acute and subacute phases.

Canine rangeliosis, caused by Rangelia vitalii, is an extravascular hemolytic disease. This study aimed to establish a clinical classification of the disease into acute and subacute phases and to describe the clinical, hematological, and pathological findings in naturally infected dogs. Eighteen dogs were included and submitted a complete blood count, serum biochemistry, ear margin blood smear, abdominal ultrasonography, polymerase chain reaction for R. vitalii and Babesia spp., and three dogs were necropsied. All animals were positive for R. vitalii and negative for Babesia spp. The most consistent findings in the acute phase included thrombocytopenia, macrocytosis, Howell-Jolly bodies, coarse hypoechoic splenomegaly, hyperthermia, and tachycardia. In the subacute phase, findings included moderate thrombocytopenia, macrothrombocytes, anisocytosis, and polychromasia, anemia, coarse hypoechoic splenomegaly, hypoproteinemia and hypoalbuminemia, increased urinary gamma-glutamyl transferase levels, lethargy, and anorexia. Thrombocytopenia and splenomegaly were the most frequent alterations, present in all cases. In blood smears, the protozoan was in its free form in 61.1 % of cases. The pathological findings were characteristic of extravascular hemolytic disease, with the most severe tissue parasitism was observed in the intestine, heart, pancreas, and bladder. This study to describe the clinical features of rangeliosis, emphasizing a clinical classification of the disease into to acute and subacute phases.