1例人感染巴贝虫的诊断与病原体鉴定

目的对首诊为疟原虫感染的巴贝虫感染者进行确诊及临床诊治情况分析。方法收集患者的临床发病资料,并对患者及其居住环境进行流行病学调查;采集骨髓样和血样,吉氏染色涂片后镜检;并以巴贝虫(Babesia)18s核糖体RNA属和种特异性引物分别扩增患者血样基因组DNA,扩增产物测序后进行BLAST分析。结果该患者反复发热20余天,出现贫血(红细胞2.59×1012和血红蛋白5.5 g/L),CT示肝脾肿大。骨髓涂片和外周血涂片吉氏染色后镜检,发现有疑似恶性疟原虫或巴贝虫感染。经流行病学调查,该患者无外出史,但有输血史和被蜱叮咬史。患者血样经巴贝虫属和种特异性引物扩增,分别出现约400 bp和1 600 bp条带。测序的序列经BLAST分析,与田鼠巴贝虫(Babesia microti)的同源性为99%,登录号分别为JQ609305和JQ609304。结论结合患者的临床发病资料、流行病学史、病原学和分子生物学检测结果,确诊为田鼠巴贝虫感染。

Pathogen identification and clinical diagnosis for one case infected with Babesia

Objective To identify the pathogen and make diagnosis on a case who was misdiagnosed as malaria.Methods Clinical and epidemiological information of the suspected case was collected.Blood samples during hospitalization were collected and examined microscopically.Genomic DNA from the blood samples was amplified by Babesia 18S RNA genus-and species-specific primers,respectively,and the amplified products were used in sequencing and BLAST sequence analysis.Results The case had a fever over 20 days repeatedly with anaemia(RBC 2.59×1012,HB 5.5 g/L) and hepatosplenomegaly.The unidentified parasites were found in the bone marrow and blood smear after Giemsa staining.Epidemiological information revealed that this case had a history of blood transfusion and tick bites.1 625 bp and 449 bp band generated by PCR amplification from blood sample using Babesia genus-and species-specific primers,and the sequence homology was 99% in comparison to Babesia microti(AB241632) with BLAST analysis.Conclusion The clinical information,epidemiological history,and the PCR identification confirm the diagnosis of Babesia microti infection.