马源人乳头瘤病毒18型的鉴定及遗传进化分析

Identification and genetic analysis of equine-origin human papillomavirus 18

为了解新疆地区马携带病毒的多样性,本研究采集新疆昌吉市和伊宁市30匹纯血马,147匹本土马粪便、鼻拭子和血清样品,采用高通量测序检测马携带病毒多样性。结果显示马粪便携带人乳头瘤病毒18型(HPV18)。根据GenBank中HPV18参考株E6基因序列,设计特异性引物,对样品进行PCR检测。结果显示20%(6/30)纯血马粪便样品携带HPV18,与其同场饲养的本土马粪便样品HPV18阳性率为12.7%(7/55),非同场饲养的本土马粪便样品HPV18阴性(0/92),表明马源HPV18可能是由纯血马携带的病毒。此外,马鼻拭子和血清样品中未检测到HPV18,表明该病毒可能仅存在于马肠道中,这也是本研究首次在动物肠道中检测到HPV18。马源HPV18 E6基因核苷酸和氨基酸序列与国外HPV18 E6基因与氨基酸序列同源性为99.6%~100%、100%,与我国HPV18 E6基因与氨基酸序列同源性为94.6%~97.3%、91.8%~96.8%,与马乳头瘤病毒E6基因与氨基酸序列同源性为35.8%~40.1%、14.6%~24.6%。遗传进化分析显示马源HPV18与国外HPV18亲缘关系较近,而与马乳头瘤病毒处于不同分支,表明马源HPV18可能是由纯血马携带的外来病毒。本研究首次鉴定了马源HPV18并对其E6氨基酸进行遗传进化分析,为HPV18的流行病学研究提供了参考依据。

To investigate the diversity of viruses carried by horses in Xinjiang,this study collected 30 thoroughbred horses samples and 147 indigenous horses samples of equine feces,sera and nasal swabs from Changji City and Yining City of Xinjiang,and high-throughput sequencing was performed to detect viral diversity carried by horses.Virome analysis revealed that equine feces had human papillomavirus type 18(HPV18).In order to understand the genetic evolution of equine-origin HPV18,specific primers were designed based on the E6 gene sequence of HPV18 reference strain in GenBank,and the samples were tested by PCR.The results showed that 20%(6/30)thoroughbred horses feces were HPV18 positive,and 12.7%(7/55)for indigenous horses co-feeding with thoroughbred horses.However,feces of indigenous horses feeding separate from thoroughbred horses were negative for HPV18(0/92).This indicated that equine-origin HPV18 might be carried by thoroughbred horses.In addition,HPV18 was not detected in horse nasal swabs and sera,suggesting that the virus might exist only in the horse’s intestine.It was the first time that HPV18 was identified in the intestine of animals.The E6 gene nucleotide and amino acid homology of equine-origin HPV18 with foreign HPV18 was 99.6%-100%and 100%,with HPV18 in China was 94.6%-97.3%and 91.8%-96.8%,and with equine papillomaviruses was35.8%-40.1%and 14.6%-24.6%.Genetic evolution analysis showed that equine-origin HPV18 was closely related to foreign HPV18,but it was in different branches from equine papillomaviruses,indicating that equine-origin HPV18 may be imported by thoroughbred horses.This study identified equine-origin HPV18 and took genetic evolution analysis on its E6 gene.These findings provide fundamental data for the prevention,control and epidemiological study of HPV18.