Rangelia vitalii, a tick-borne piroplasm that infects dogs, has been recently molecularly characterized in Brazil, Uruguay and Argentina. Studies on molecular characterization of these piroplasms in different Brazilian regions are scarce. The aim of this study was to evaluate clinical and hematological changes in dogs caused by R. vitalii in the mountainous region of the state of Rio de Janeiro. Blood samples from 36 dogs were evaluated for piroplasms and hematological disorders using light microscopy and molecular analysis. Blood samples from all the animals included in this study were confirmed to be positive for R. vitalii through genetic sequencing. Clinical signspresented by 24 of the 36 dogs of the study were evaluated during appointments or hospitalization within private practice. The most frequent clinical disorders in these dogs that were naturally infected with R. vitalii were fever, spontaneous cutaneous bleeding and diarrhea. Normochromic non-regenerative anemia and thrombocytopenia were the most common hematological disorders in these R. vitalii-positive dogs and therefore should be considered in hematological evaluations on suspected cases.Keywords: Piroplasm, Rangelia vitalii, dogs, PCR, hematological evaluation.
ResumoRangelia vitalii, um piroplasma transmitido por carrapatos que infecta cães, foi sendo recentemente caracterizado molecularmente no Brasil, Uruguai e Argentina. Nas diferentes regiões brasileiras são escassos os estudos acerca da caracterização molecular destes piroplasmídeos. O objetivo deste estudo foi avaliar as alterações clínicas e hematológicas em cães causadas por R. vitalii na região serrana do Rio de Janeiro. Amostras de sangue total de 36 cães foram examinadas quanto à presença de piroplasmas pela microscopia de luz, alterações hematológicas e análise molecular. Todos os cães do presente estudo foram positivos para R. vitalii através do sequenciamento genético. Dos 36 animais positivos para R. vitalii, 24 foram avaliados clinicamente. As alterações mais frequentemente observadas foram febre, sangramento cutâneo espontâneo e diarréia. Anemia normocítica normocrômica arregenerativa e trombocitopenia foram as alterações hematológicas mais observadas em cães positivos para R. vitalii, devendo ser consideradas na avaliação hematológica de cães suspeitos.