Vahle J L, Haynes J S, Andrews J J
Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames 50011-1250, USA.
J Vet Diagn Invest. 1995 Oct;7(4):476-80. doi: 10.1177/104063879500700409.
Haemophilus parasuis is a common cause of polyserositis and polyarthritis in swine. Little is known about the mucosal and systemic sites of replication and lesions which follow an aerosol exposure to H. parasuis. In this experiment 5-week-old cesarean-derived, colostrum-deprived (CDCD) pigs were inoculated intranasally with an inoculum containing 2 x 10(9) colony-forming units of H. parasuis. Two principals and one control pig were necropsied at 12, 36, 84, and 108 hours postinoculation (PI) and samples obtained for bacteriologic culture and microscopic examination. Inoculated pigs developed clinical signs of inappetence, reluctance to move, lameness, and a serous nasal discharge. Macroscopic findings included a fibrinous polyserositis and polyarthritis 36 hours PI which became progressively more severe at 84 and 108 hours PI. No lung lesions were grossly visible. Microscopic lesions included a mild purulent rhinitis at each post inoculation interval and fibrinous to fibrinopurulent synovitis and serositis at 36, 84, and 108 hours PI. A focal suppurative bronchopneumonia was observed in one pig examined at 36 hours PI. The nasal cavity and trachea were the only mucosal sites from which H. parasuis was reisolated. Haemophilus parasuis was isolated from the blood and systemic sites at 36, 84, and 108 hours PI. Findings presented indicated that intranasal inoculation of 5-week-old CDCD pigs with H. parasuis results in clinical signs and lesions of polyserositis and polyarthritis typical of field cases and is a useful model for the study of H. parasuis pathogenesis. The results also suggest that H. parasuis initially colonizes the nasal mucosa.
副猪嗜血杆菌是猪多浆膜炎和多关节炎的常见病因。关于经气溶胶暴露于副猪嗜血杆菌后其在黏膜和全身的复制部位以及病变情况，人们了解甚少。在本实验中，对5周龄剖腹产、未吮初乳（CDCD）的仔猪经鼻接种含2×10⁹菌落形成单位副猪嗜血杆菌的接种物。在接种后（PI）12、36、84和108小时，对2头主要实验猪和1头对照猪进行剖检，并采集样本进行细菌培养和显微镜检查。接种后的猪出现食欲不振、不愿活动、跛行和浆液性鼻液等临床症状。宏观检查结果包括接种后36小时出现纤维素性多浆膜炎和多关节炎，在接种后84和108小时病情逐渐加重。肉眼未见肺部病变。显微镜下病变包括在每个接种后时间间隔均有轻度脓性鼻炎，在接种后36、84和108小时有纤维素性至纤维蛋白脓性滑膜炎和浆膜炎。在接种后36小时检查的1头猪中观察到局灶性化脓性支气管肺炎。鼻腔和气管是唯一能再次分离出副猪嗜血杆菌的黏膜部位。在接种后36、84和108小时从血液和全身部位分离出副猪嗜血杆菌。呈现的结果表明，对5周龄CDCD仔猪经鼻接种副猪嗜血杆菌会导致出现多浆膜炎和多关节炎的临床症状及病变，这是典型的田间病例表现，也是研究副猪嗜血杆菌发病机制的有用模型。结果还表明，副猪嗜血杆菌最初定殖于鼻黏膜。
