Ignjatovic J, Ashton D F, Reece R, Scott P, Hooper P
CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria 3220, Australia.
J Comp Pathol. 2002 Feb-Apr;126(2-3):115-23. doi: 10.1053/jcpa.2001.0528.
The pathogenicity of 25 strains of infectious bronchitis virus (IBV) isolated in Australia between 1961 and 1994 was compared in white leghorn specific pathogen-free chicks. Twelve strains were nephropathogenic and 10 respiratory, the other three being of mixed pathogenicity. The IBV strains identified as nephropathogenic induced clinical nephritis, gross and histological kidney lesions, and mortality of 5-90%. According to the severity of these features, the nephropathogenic strains could be further subdivided into strains of high, moderate or low pathogenicity. The three strains of mixed pathogenicity induced tracheitis, mild clinical nephritis and kidney lesions but no mortality. The 10 respiratory strains caused histological lesions in the trachea but not in the kidney, and did not induce clinical nephritis or mortality. Of 12 IBV strains isolated between 1961 and 1976, nine were nephropathogenic, inducing mortality of 15-90%. In contrast, of 13 strains isolated between 1981 and 1994, only three were nephropathogenic, inducing mortality of 5-37%, whereas nine were respiratory. Seven of these nine strains, unlike other respiratory strains, failed completely to replicate in the kidney. The results indicated a change in the prevalent IBV strains from highly nephropathogenic (1960s to 1970s) to respiratory (1980s to early 1990s); moreover, the late 1980s saw the emergence of respiratory strains with altered tissue tropism.
对1961年至1994年间在澳大利亚分离出的25株传染性支气管炎病毒（IBV）在白来航无特定病原体雏鸡中进行了致病性比较。12株为肾致病性，10株为呼吸道致病性，另外3株具有混合致病性。被鉴定为肾致病性的IBV毒株可引发临床肾炎、肾脏大体病变和组织学病变，死亡率为5%至90%。根据这些特征的严重程度，肾致病性毒株可进一步细分为高致病性、中度致病性或低致病性毒株。3株具有混合致病性毒株引发气管炎、轻度临床肾炎和肾脏病变，但无死亡。10株呼吸道致病性毒株在气管中引发组织学病变，但在肾脏中未引发病变，也未诱发临床肾炎或死亡。在1961年至1976年间分离出的12株IBV毒株中，9株为肾致病性，死亡率为15%至90%。相比之下，在1981年至1994年间分离出的13株毒株中，只有3株为肾致病性，死亡率为5%至37%，而9株为呼吸道致病性。这9株中的7株与其他呼吸道致病性毒株不同，在肾脏中完全无法复制。结果表明，流行的IBV毒株发生了变化，从高肾致病性（20世纪60年代至70年代）转变为呼吸道致病性（20世纪80年代至90年代初）；此外，20世纪80年代末出现了组织嗜性改变的呼吸道致病性毒株。
