１９９５年作者从湖北濒死鹦鹉体内分离到一株新病毒，经鹦鹉胚成纤维细胞盲传四代过渡到鸡胚成纤维细胞，再传至第五代出现细胞病变。适应细胞的病毒纯化后，经ＳＤＳＰＡＧＥ分析，发现病毒粒子结构蛋白由８条多肽组成，分子量范围在１４．５～６０ｋＤ之间。病毒的酸碱氨基酸之比为２．５１，富含Ａｓｐ、Ｃｌｕ和Ｌｅｕ，而Ａｒｇ和Ｍｅｔ含量较少。病毒核酸为双链ＤＮＡ，存在超螺旋型、环型和线型三种形态，Ｇ＋Ｃ的含量为４５％。经限制性内切酶分析，核酸的分子量为３．３１０６Ｄ。根据病毒分类的标准确认为澳州长尾小鹦鹉幼雏病病毒，应归属于乳多空病毒科多瘤病毒属。

A strain of new virus was isolated from fledgling budgerigars by authors in 1995 Cytopathic effect became visible after the isolate was passaged 4 generations on budgerigar embryo fibroblast and 5 generations on Chicken embryo fibroblast．The SDS-PAGE proved that viral capsidxgas composed of eight polypeptides with molecular w |gbt from 60 000 tO 14 500 D．The protein WBtS rich in Asp，Glu and Leu，but comparatively poorer in Arg and M et．The ratio of acidicamino acid to basic amino acid WBS l：2．5 l T nudeic acid Was dsDNA and exi~ed as supercoiled circular．relaxed ciseulatand Iinear molecules G 十C of viral DNA was 45％ The molecu 1ar weight oE DNA WBtS 3．3 106D restriction endonuclease analysis According to standards of virus classification．it is proved that the isolate was budgerigar fledgling disease virus which had placed into the Polyomavirus genus of Papovaviridae．