脊髓灰白质炎病毒为一种裸露的细小病毒,在球形的衣壳内包蔽着一分子的单链RNA.基因组RNA为正极性链,衣壳由多肽VP_1与VP_3各60个拷贝,多肽VP_2与VP_4各58～59个拷贝以及VP_2与VP_4的前体VP_01～2个拷贝等所组成.病毒粒 The myelo-parvovirus is a naked parvovirus that encloses a single-stranded RNA within a spherical envelope.The genomic RNA is a positive-polarity strand and the capsid consists of 60 copies of each of the VP_1 and VP_3 polypeptides. The VP2 and 58 ~ 59 copies of VP_4 and VP_01 ~ 2 copies of VP_2 and VP_4, etc. The virion