牦牛源正呼肠孤病毒2型的检测和分离鉴定

旨在调查川西北牦牛哺乳动物正呼肠孤病毒（MRV）的感染情况并分离病毒。采用RT-PCR方法，对采自川西北15个牧场的72份牦牛腹泻粪便样本和其中5个牧场的15份腹泻牦牛血清样本进行MRV检测，阳性样本进一步用分型PCR确定其血清型。结果显示，粪便样本中MRV检出率为20.83%（15/72），血清2型的比例为60%（9/15）；血清样本中MRV检出率为40%（6/15），血清2型的比例为83.33%（5/6）；未检测到其他血清型。成功地从腹泻粪便中分离到1株MRV血清2型毒株（TCID₅₀为4×10^-8.56·mL^-1），并获得长度为23 587 bp的分离株全基因组，该分离株与中国猪源毒株的遗传关系最近；与GenBank中所有的MRV S1基因相比，该分离株有4个独特的氨基酸突变。本研究从牦牛中检测到MRV，并分离到1株牛源MRV血清2型毒株，为进一步研究MRV血清2型生物学特性奠定了基础。

Detection,Isolation and Identification of Mammalian Orthoreovirus Serotype 2 in Yaks

This study aimed to investigate the infection of mammalian orthoreovirus (MRV) in Northwest Sichuan yaks and isolate MRV from positive samples. 72 fecal samples of diarrhea yaks from 15 pastures in northwest Sichuan and 15 serum samples of diarrhea yaks from 5 pastures were collected for detecting MRV by PT-PCR, and the positive samples were further serotyped by PCR assay. The results showed that the detection rates of MRV in diarrhea samples and serum samples were 20.83% (15/72) and 40% (6/15), respectively; and MRV2 was 60% (9/15) in MRV-positive diarrhea samples and 83.33% (5/6) in MRV-positive serum samples, respectively; other serotypes were not detected. One strain of MRV2 (TCID₅₀ is 4×10^-8.56·mL^-1) was isolated from a fecal sample, and its complete genome was successfully sequenced with 23 587 bp in length. In phylogenetic analysis of MRV genomes, the strain yak/AB14/2018 is closely related to China swine strains. Compared with all S1 sequences availble in GenBank, this strain shared 4 amino acids variations. In conclusion, MRV was detected from yaks, and one MRV2 strain was successfully isolated, contributing to further research the biological characteristics of MRV2.