Molecular evaluation of piroplasms and hematological changes in canine blood stored in a clinical laboratory in Niterói, Rio de Janeiro

Abstract Piroplasm species were analyzed by molecular tools in total 31 blood samples from positive dogs, previously checked by stained slides, stored until DNA extraction between 2016 to 2018 in the laboratory Clinical Analyzes in Niterói, Rio de Janeiro. The piroplasms were identified by PCR, targeting the 18S rRNA gene and sequencing. From the total number of samples only 24 (77.4%) were positive and show adequate nucleotide sequences for interpretation with identity between 93%-100% with Babesia vogeli in compared to the sequences isolated of infected dogs from other states in Brazil deposited on GenBank. Most of dogs infected with B. vogeli had anemia (62.5%) and thrombocytopenia (95.8%). The findings of this study are compatible with previous reports in the literature and highlight B. vogeli as the most incriminated species in canine piroplasmosis in Brazil, and thrombocytopenia the hematological alteration most frequently identified in this infection. It is important to note that this is the first study involving the molecular characterization of piroplasms in the metropolitan region of Rio de Janeiro, based on PCR followed by sequencing.

摘要：本研究采用分子生物学检测手段，对31份经染色血涂片镜检确诊的犬只血液样本开展梨形虫（Piroplasm）物种鉴定。所有样本于2016至2018年间保存于巴西里约热内卢尼泰罗伊市临床分析实验室，直至进行DNA提取。本研究以18S rRNA基因为扩增靶标，通过聚合酶链式反应（PCR）结合测序技术完成梨形虫鉴定。所有样本中仅24份（77.4%）检测结果为阳性，且获得了可供分析的合格核苷酸序列；经与GenBank中提交的巴西其他州感染犬只分离的沃氏巴贝斯虫（Babesia vogeli）序列比对，其同源性达93%~100%。感染沃氏巴贝斯虫的犬只中，多数表现为贫血（62.5%）与血小板减少症（95.8%）。本研究结果与既往文献报道相符，明确沃氏巴贝斯虫为巴西犬梨形虫病的主要致病物种，且血小板减少症是该感染中最常见的血液学异常。值得注意的是，本研究是首个基于PCR结合测序技术，对里约热内卢大都市区犬梨形虫进行分子鉴定的研究。