马源人乳头瘤病毒115型E6基因的遗传变异分析

Genetic analysis of horse-origin human papillomavirus type 115 E6 gene

乳头瘤病毒(PV)是人类和动物的一种重要病原体,具有严格的宿主特异性。已报道14种PV可以感染马,其中在我国新疆地区发现马携带马乳头瘤病毒1型(EcPV-1)、人乳头瘤病毒18型(HPV-18)和HPV-23。为进一步调查新疆地区马匹携带PV的类型,本研究利用高通量测序和病毒宏基因组学技术检测伊犁、昌吉3个规模化马场和乌鲁木齐1个马术俱乐部395份样品(205份鼻拭子、140份粪便样品及50份马流产胎儿肺组织样品)携带PV的类型。病毒组学分析显示,马可能携带HPV-115。根据注释到的HPV-115 E6基因序列,设计特异性引物,对所有马及人鼻拭子样品进行E6基因的PCR检测,结果显示,伊犁地区B场马鼻拭子样品中的HPV-115阳性率为7.3%(6/82),其他马场及马术俱乐部的纯血马和汗血马均为阴性,表明HPV-115可以跨种感染马。另外该病毒在B场马流产胎儿肺组织样品中的阳性率为46%(23/50),表明马感染HPV-115可能导致流产。进一步调查显示,HPV-115在马场工人和有阳性马场接触史的人群鼻拭子样品中的阳性率为59.5%(25/42),而无马匹接触史人员鼻拭子样品则呈阴性(0/20),表明该马源HPV-115有经马感染人的风险。同源性分析结果显示本研究测序获得的11株HPV-115 E6基因核苷酸和氨基酸序列同源性分别为99.0%~100%、98.1%~100%;与人源HPV-115参考株GC02 E6基因核苷酸和氨基酸序列同源性分别为98.4%~99.0%、97.1%~99.0%;与EcPV E6基因核苷酸和氨基酸序列同源性分别为32.4%~43.8%、34.6%~45.4%。E6基因的遗传进化分析显示本研究鉴定的11株马源和人源HPV-115形成独立进化分支。本研究首次报道HPV-115可能导致马流产,且其具备经马感染人的风险,该结果为马源HPV感染的防制提供了参考依据。

Papillomavirus(PV) is an important pathogen infecting both human and animal, but the virus has strict host specificity. 14 species of papillomaviruses have been reported to infect horses to date. Of these, horse-origin PV, HPV-18, HPV-23and EcPV-1 had been detected in horses of North Xinjiang, China. In order to understand the types of PV circulating in horses in North Xinjiang, 395 samples(205 nasal swabs, 140 fecal samples and 50 aborted fetal lung tissue) are collected from three largescale breeding farms in Yili and Changji, and one equestrian club in Urumqi, and the viral metagenomic sequencing was applied to detect the types of PVs in horses. The resulting metagenomic data showed that HPV-115 was present in samples. According to the HPV-115 reference strain GC02, specific primers against E6 gene were designed to verify the results of viral metagenomics. PCR results showed that six nasal swabs of farm B in Yili were positive for HPV-115, with a positive rate was 7.3%(6/82), In addition,the positive rate of the virus in aborted fetal lung tissue of Yili horses collected from farm B was 46%(23/50), thereby indicating that HPV-115 might be a new pathogen causing of abortions in horse, Further investigation revealed that the horse-origin HPV-115might spill over to workers in HPV-115-positive farm in Yili. Sequences analysis indicated that the homology of nucleotides and amino acid among our detected HPV-115 E6 was 99.0%-100%, 98.1%-100% respectively. It shared 98.4%-99.0% nucleotide sequence identity and 97.1%-99.0% amino acid sequence identity with E6 gene of human origin HPV-115 reference strain GC02,but shared 32.4%-43.8% nucleotide sequence identity and 34.6%-45.4% amino acid sequence identity with E6 gene of EcPVs. The phylo-genetic tree based on the sequences of E6 gene showed that 11 horse-origin and human-origin HPV-115 detected in this study were clustered in an independence lineage. These results provide new evidence that HPV-115 can infect horses, may act as a causative agent for abortions in Yili horses, and infect humans laboring in Yili mare stables.