Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, Pretoria, South Africa; Department for Companion Animals and Horses, University of Veterinary Medicine, Vienna, Veterinärplatz 1, 1210, Vienna, Austria.
Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, Medical School Hannover (MHH) - Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Strasse 7, 30625, Hannover, Germany.
Vet Microbiol. 2018 Sep;223:51-58. doi: 10.1016/j.vetmic.2018.07.015. Epub 2018 Jul 21.
Since the discovery of equine hepacivirus (EqHV) in 2011, the virus has been detected in horse populations from more than twelve countries across five continents. EqHV seroprevalence has been reported to be as high as 61.8% and EqHV ribonucleic acid (RNA) prevalence to range between 0.9% and 34.1%. Molecular and serological indications of EqHV infection have never been reported in equids on the African continent. Therefore, investigation of EqHV prevalence in South African horses and subsequent viral genetic characterization contribute to a better understanding of the global epidemiology of this virus. In a cross-sectional study, serum samples from 454 Thoroughbred foals (aged 58-183 days) were analysed for anti-EqHV non-structural protein 3 (NS3)-specific antibodies (abs) with a luciferase immunoprecipitation system (LIPS) and for EqHV RNA by quantitative real-time polymerase chain reaction (qRT-PCR). Farms of origin (n = 26) were situated in South Africa's Western Cape Province. The associations between EqHV infection state and farm of origin, foal gender and foal age were subsequently described. Furthermore, nested PCRs were performed on parts of the 5'UTR, NS3 and NS5B genes of 17 samples. Samples were sequenced and phylogenetic analyses were conducted. The population's seroprevalence was 83.70% and RNA was detected in 7.93% of samples. Increasing foal age was associated with decreasing ab prevalence and increasing prevalence of EqHV RNA. Sequences from South African EqHV strains did not show in-depth clustering with published sequences of EqHV isolates from particular continents. In conclusion, EqHV is present in the South African Thoroughbred population and appears more prevalent than reported in other horse populations worldwide.
自 2011 年发现马属动物乙型肝炎病毒（EqHV）以来，该病毒已在来自五大洲的 12 个以上国家的马群中被检测到。报道称，EqHV 的血清阳性率高达 61.8%，EqHV 核糖核酸（RNA）的阳性率在 0.9%至 34.1%之间。在非洲大陆的马属动物中从未报告过 EqHV 感染的分子和血清学迹象。因此，调查南非马属动物中 EqHV 的流行情况以及随后对病毒遗传特征的分析有助于更好地了解该病毒的全球流行病学。在一项横断面研究中，使用荧光素酶免疫沉淀系统（LIPS）分析了来自 454 匹纯血马驹（58-183 日龄）的血清样本，以检测抗 EqHV 非结构蛋白 3（NS3）特异性抗体（Abs），并使用定量实时聚合酶链反应（qRT-PCR）检测 EqHV RNA。原籍农场（n=26）位于南非西开普省。随后描述了 EqHV 感染状态与原籍农场、驹性别和驹龄之间的关系。此外，对 17 个样本的 5'UTR、NS3 和 NS5B 基因的部分区域进行了巢式 PCR。对样本进行测序，并进行系统发育分析。该人群的血清阳性率为 83.70%，有 7.93%的样本检测到 RNA。驹龄的增加与抗体阳性率的降低和 EqHV RNA 阳性率的增加有关。来自南非 EqHV 株的序列与特定大陆公布的 EqHV 分离株的序列没有深入聚类。总之，EqHV 存在于南非纯血马群中，其流行率高于全球其他马群报道的流行率。
