An infectious eiav clone was recovered by transfecting fatal donkey dermal ( fdd ) cell cultures and donkey leukocyte ( dl ) culture in vitro with the full - length gene clone of dv . the virus ( designed pd70344v ) derived from the third passage in dl culture was observed by electron microscope and the reverse transcriptase ( rt ) activity was determined 将包含全基因片段的三个基因克隆以限制性内切酶消化后顺次连接克隆到载体ptz18r上，构建了4个全长基因的分子克隆，分别命名为pd30343 、 pd70333 、 pd70343 、 pd70344 ，其中两个转移到低拷贝载体plg338上，命名为plgd30343 、 plgd70344 。
