链球菌2型对恩施黑猪和美系纯种长白猪的致病性研究

STUDY ON PATHOGENIC MECHANISM OF STREPTOCOCCUS SUIS SEROTYPE 2 TO BLACK PIGS IN ENSHI AND AMERICAN LANDRACE

猪链球菌(Streptococcus suis,S.suis)病是一种能够引起人和多种动物发病的重要人畜共患病,其中以2型(SS2)流行最广,致病力最强,不仅可引起猪脑膜炎、关节炎、心内膜炎、败血症、肺炎和突然死亡,还可以感染人并致其死亡,严重地威胁着人类的公共卫生安全。本研究对恩施黑猪和美系长白猪进行猪链球菌2型的攻毒试验,观察其病理损害,进而探讨其致病机制。20头猪分A、B、C、D四个组,A组为5头恩施黑猪,B组为5头美系长白猪,C、D两组作为空白对照组。A、B组感染猪链球菌2型菌株,攻毒后都出现出现体温升高、跛行和神经症状,但A组恩施黑猪更加明显,出现3头死亡,解剖后各组织器官病变也比美系长白猪明显。通过对病理器官组织切片、细菌学检验、细菌计数等结果,恩施黑猪对链球菌2型的易感性比美系长白猪更强,从而证实了猪链球菌2型对鄂西黑猪的致病性比美系长白猪更强。

Streptococcus suis disease is an important zoonotic disease in humans and animals. Serotype 2 is the most prevalent and virulent, causing meningitis, arthritis, inflammation, sepsis, pneumonia and sudden death in pigs. In the present study, the pathogenicity of S. suis Serotype 2 was investigated in the Enshi black pigs native to western Hubei province and American Landrace. Twenty pigs were divided into four groups, 5 pigs each. Five Enshi black pigs and other 5 American Landrace pigs were infected with S. suis Sero type 2 strain. Non-infected controls included 5 Enshi black pigs and 5 American Landrace pigs. All infected pigs developed high body temperature, lameness and neurological signs. The Enshi black pigs showed more severe disease and pathological changes than American Landrace pigs. Three Enshi black pigs died. Examinations for clinical signs, histopathology and bacteriological isolation indicated that the Enshi black pigs were less susceptibility to S. suis Sero type 2 infection than American Landrace pigs.