血清4型和5型副猪嗜血杆菌易感仔猪发病模型的建立

Establishment of a Disease Model for Piglets Susceptible to Haemophilus parasuis Serotypes 4 and 5

为建立副猪嗜血杆菌(HPS)的仔猪发病模型,本试验使用HPS血清4型(SD-05、ZC-7)、血清5型(HB-08、PZ-26)菌株对仔猪进行毒力测定,然后以2种血清型最适菌株的最适剂量通过腹腔注射,对21~28日龄健康易感断奶仔猪开展攻毒试验,观察其临床症状和剖检变化,并对死亡仔猪进行细菌分离及PCR鉴定。结果显示:血清4型SD-05株、血清5型HB-08株毒力较强,对仔猪的最适接种剂量分别为4.8×10^(9)、4.7×10^(9) CFU。攻毒后仔猪出现精神沉郁、呼吸困难、咳嗽、消瘦、跛行、可视黏膜发绀等临床症状,剖检可见胸腹腔内和脏器表面有纤维素性渗出物,心脏出现“绒毛心”等病理变化。在仔猪组织器官中成功分离到HPS血清4型SD-05株和血清5型HB-08株。结果表明,本研究初步建立了血清4型和5型HPS感染的仔猪发病模型,为其致病机制、诊断和免疫研究奠定了基础。

In order to establish a piglet disease model of Haemophilus parasuis(HPS),the virulence on piglets was determined by the strains of HPS serotypes 4(SD-05 and ZC-7)and 5(HB-08 and PZ-26),then the optimal strains of the two serotypes were injected respectively and intraperitoneally into healthy and susceptible weaned piglets aged 21 to 28 days old at the optimal dose to observe their clinical symptoms and pathological changes,followed by bacterial isolation and identifi cation by PCR on dead piglets.The results showed that the strains of serotypes 4(SD-05)and 5(HB-08)were with strongest virulence at the optimal doses of 4.8×10^(9) CFU and 4.7×10^(9) CFU respectively.Clinical symptoms such as depression,dyspnea,cough,emaciation,claudication,visible mucosal cyanosis,etc.,were observed in the challenged piglets,and pathological changes such as fi brinous exudates from surface of visceral organs and within pleuroperitoneal cavities,“trichocardia”appeared in hearts were observed through autopsy.The strains of HPS serotypes 4(SD-05)and 5(HB-08)were successfully isolated from tissues and organs of piglets.It was concluded that a disease model for piglets infected with HPS serotypes 4 and 5 was established in the study,which laid a foundation for future study on the pathogenesis,diagnosis and immunity against HPS.