目的 探讨河南省信阳市发热伴血小板减少患者中巴贝虫感染分子流行特征,为信阳市及河南省巴贝虫病的防治提供依据。方法 采集信阳市2012年有发热伴血小板减少症状患者的血样和基本信息。提取血样DNA,用两对引物（Bab5/Bab8 + Bab6/Bab7和 RIB-19/RIB-20 + BAB-rumF/BAB-rumR）巢式PCR扩增巴贝虫18S rRNA基因,测序后与GenBank中田鼠巴贝虫的相应序列进行比对。对血样检测阳性的病例进行地区、发病时间、人群、蜱虫叮咬和布尼亚病毒检测情况的分析。结果 共收集600例有发热伴血小板减少症状的患者血样,59例（9.8%）血样两对引物巢式PCR均扩增出约430 bp的18S rRNA基因片段。序列比对结果显示,59条扩增序列与田鼠巴贝虫（GenBank登录号：LC314655.1）的一致性均高于97%。59例血样扩增阳性中,51例来自信阳市（86.4%）,其中商城县16例（27.1%）,光山县12例（20.3%）;发病时间集中在5月（23.7%,14/59）、6月（39.0%,23/59）和7月（17.0%,10/59）;患者以中老年人为主,40岁以上者48例（81.4%,48/59）。59例阳性病例中14例（23.7%）曾被蜱虫叮咬,31例（2.5%）布尼亚病毒检测阳性。结论 河南省信阳市发热伴血小板减少患者中巴贝虫感染率较高,尤其中老年患者。

Objective To study the molecular epidemiology of babesiosis in cases of fever with thrombocytopenia in Xinyang City and provide basis for the control of babesiosis. Methods Blood samples and epidemiological information were collected from 600 patients who had fever and thrombocytopenia in Xinyang City in 2012. The DNA was extracted from the blood samples and Babesia 18S rRNA was amplified by nested-PCR with two sets of primers Bab5/Bab8 + Bab6/Bab7 and RIB-19/RIB-20 + BAB-rumF/BAB-rumR. The PCR products were sequenced and aligned with Babesia mocroti sequences in genome database. The PCR positive cases were further analyzed for their epidemiological characteristics, history of tick bite and bunyavirus infection. Results Totally 600 blood samples were collected from patients who had fever and thrombocytopenia, 59 (9.8%) of them were PCR positive with a fragment of 430 bp amplified by both sets of primers. The amplified 18S rRNA sequences shared more than 97% identity to LC314655.1 of B. mocroti. Among the 59 positive cases, 51 (86.4%) were from Xinyang City, 16 from Shangcheng County (27.1%) and 12 from Guangshan County (20.3%). The fever onset mostly happened in summer including 14 in May (23.7%), 23 in June (39.0%) and 10 in July (17.0%). Most of cases were middle-aged or elderly and 48 cases (81.4%) were over 40 years old. Among the 59 positive cases 14 (23.7%) had history to be bitten by ticks and 31 (52.5%) were positive for bunyavirus. Conclusion The morbidity of babesiosis is high in the cases with fever and thrombocytopenia in Xinyang City, Henan Province. People with middle-age and elderly are the most vulnerable population to be infected by Babesia during summer.