Groom S C, Little P B, Rosendal S
Department of Pathology, Ontario Veterinary College, University of Guelph.
Can J Vet Res. 1988 Jul;52(3):349-54.
Pneumonia was induced in four month old Holstein calves by intratracheal inoculation of 1 x 10(9) colony forming units of Haemophilus somnus. Twenty calves were divided into four groups of five and challenged with a pneumonic strain (Group 1), an encephalitic strain (Group 2), a preputial strain (Group 3), or a placebo (Group 4). The clinical score, neutrophil count, respiratory rate, and temperature were significantly increased in group 1 by day 1 postinoculation (P less than 0.05) and maintained until day 6 postinoculation (P less than 0.05). The macroscopic pathological changes were significantly greater in group 1 (P less than 0.05). Haemophilus somnus was consistently isolated from pneumonic tissue of group 1 only. Groups 2 and 3 had mild transient increases in all parameters measured and macroscopically only small focal lesions were present. It is concluded that virulence differences exist between H. somnus strains following intratracheal challenge of bovine lungs.
通过气管内接种1×10⁹ 菌落形成单位的睡眠嗜血杆菌，在4月龄的荷斯坦犊牛中诱发肺炎。将20头犊牛分为4组，每组5头，分别用肺炎菌株（第1组）、脑炎菌株（第2组）、包皮菌株（第3组）或安慰剂（第4组）进行攻毒。接种后第1天，第1组的临床评分、中性粒细胞计数、呼吸频率和体温显著升高（P<0.05），并持续至接种后第6天（P<0.05）。第1组的宏观病理变化显著更大（P<0.05）。仅在第1组的肺炎组织中持续分离到睡眠嗜血杆菌。第2组和第3组所测的所有参数均有轻度短暂升高，宏观上仅存在小的局灶性病变。得出的结论是，气管内攻毒牛肺后，睡眠嗜血杆菌菌株之间存在毒力差异。
