Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164-7040, USA.
Vet Microbiol. 2013 Feb 22;162(1):166-72. doi: 10.1016/j.vetmic.2012.08.029. Epub 2012 Sep 7.
Pneumonic bighorn sheep (BHS) have been found to be culture- and/or sero-positive for Bibersteinia trehalosi, respiratory syncytial virus (RSV), and parainfluenza-3 virus (PI-3). The objective of this study was to determine whether these pathogens can cause fatal pneumonia in BHS. In the first study, two groups of four BHS each were intra-tracheally administered with leukotoxin-positive (Group I) or leukotoxin-negative (Group II) B. trehalosi. All four animals in Group I developed severe pneumonia, and two of them died within 3 days. The other two animals showed severe pneumonic lesions on euthanasia and necropsy. Animals in Group II neither died nor showed gross pneumonic lesions on necropsy, suggesting that leukotoxin-positive, but not leukotoxin-negative, B. trehalosi can cause fatal pneumonia in BHS. In the second study, two other groups of four BHS (Groups III and IV) were intra-nasally administered with a mixture of RSV and PI-3. Four days later, RSV/PI-3-inoculated Group IV and another group of four BHS (Group V, positive control) were intra-nasally administered with Mannheimia haemolytica, the pathogen that consistently causes fatal pneumonia in BHS. All four animals in group III developed pneumonia, but did not die during the study period. However all four animals in Group IV, and three animals in Group V developed severe pneumonia and died within two days of M. haemolytica inoculation. The fourth animal in Group V showed severe pneumonic lesions on euthanasia and necropsy. These findings suggest that RSV/PI-3 can cause non-fatal pneumonia, but are not necessary predisposing agents for M. haemolytica-caused pneumonia of BHS.
已发现患肺炎的大角羊（BHS）对毕赤氏菌属海藻糖、呼吸道合胞病毒（RSV）和副流感病毒-3（PI-3）呈文化和/或血清阳性。本研究的目的是确定这些病原体是否会导致 BHS 发生致命性肺炎。在第一项研究中，每组 4 只 BHS 分别通过气管内给予白细胞毒素阳性（I 组）或白细胞毒素阴性（II 组）的 B. trehalosi。I 组的所有 4 只动物均发展为严重肺炎，其中 2 只在 3 天内死亡。另外 2 只动物在安乐死和剖检时表现出严重的肺炎病变。II 组动物既未死亡，剖检时也未出现明显的肺炎病变，这表明白细胞毒素阳性而非白细胞毒素阴性的 B. trehalosi 可导致 BHS 发生致命性肺炎。在第二项研究中，另外两组 4 只 BHS（III 组和 IV 组）通过鼻腔内给予 RSV 和 PI-3 的混合物。4 天后，IV 组和另一组 4 只 BHS（V 组，阳性对照）通过鼻腔内给予可引起 BHS 致命性肺炎的病原体曼海姆菌。III 组的所有 4 只动物均发展为肺炎，但在研究期间未死亡。然而，IV 组的所有 4 只动物和 V 组的 3 只动物均发展为严重肺炎，并在接种 M. haemolytica 后的两天内死亡。V 组的第 4 只动物在安乐死和剖检时表现出严重的肺炎病变。这些发现表明 RSV/PI-3 可引起非致命性肺炎，但不是曼海姆菌引起 BHS 肺炎的必要诱发因素。
