Clinical and hematological evaluation of Rangelia vitalii-naturally infected dogs in southeastern Brazil

Abstract 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.

摘要 Rangelia vitalii是一种经蜱传播、可感染犬只的梨形虫，近期已在巴西、乌拉圭及阿根廷完成其分子生物学鉴定。目前针对巴西不同地区此类梨形虫的分子生物学鉴定研究仍较为匮乏。本研究旨在评估里约热内卢州山区犬只感染R. vitalii后出现的临床与血液学变化。本研究通过光学显微镜检测与分子生物学分析，对36只犬的血液样本进行梨形虫感染及血液学异常情况评估。经基因测序确认，本研究纳入的所有受试动物血液样本均呈R. vitalii阳性。本研究纳入的36只犬中，有24只的临床症状均在私人诊所的就诊或住院期间得到评估记录。自然感染R. vitalii的受试犬中，最常见的临床症状为发热、自发性皮肤出血及腹泻。正色素性非再生性贫血与血小板减少症是此类R. vitalii阳性犬最常见的血液学异常，因此在疑似感染病例的血液学评估中应将其纳入考量范畴。