摘要
为建立稳定的猪链球菌2型(Streptococcus suis type 2,SS2)人工发病模型,本试验以天津某发病猪场分离的SS2 Y15293株为研究对象,经腹腔注射感染昆明小鼠,测定其LD_(50),确定造模感染剂量,通过观察感染后小鼠的临床症状和病理变化,测定试验期间各组小鼠体重和采食量的变化及细菌回归等试验对模型进行评估。结果显示,SS2 Y15293株致昆明小鼠的LD_(50)为6.7×10~7 CFU/mL。以1个LD_(50)的剂量攻毒,与对照组相比,试验小鼠主要发病表现为攻菌后24 h出现精神沉郁、被毛逆立、眼睛有分泌物,72～96 h出现头颈歪斜、翻滚、震颤等神经症状,死亡高峰在48～72 h。3次重复试验中,试验组小鼠的发病率均为100%,死亡率为50%～70%,神经症状小鼠出现比率20%～30%。与对照组相比,试验组小鼠采食量和体重显著下降(P<0.05),临床症状分值显著升高(P<0.05)。组织病理检查发现,试验组小鼠心脏、肺脏组织均有不同程度出血、炎性细胞浸润;脑膜炎,脑室出血,充满炎性细胞。细菌回归试验结果表明,试验组死亡小鼠脑、心脏、肝脏、脾脏、肺脏、肾脏均有细菌定植,且形态、染色和分子生物学特性与攻毒菌一致。以上结果证实,SS2 Y15293株能感染昆明小鼠并致其发病,感染动物发病规律性强,重复性好,临床症状典型,说明SS2 Y15293株感染昆明小鼠可作为SS2的候选人工感染模型。
In order to establish a stable model of Streptococcus suis type 2 (SS2) artificial disease model,the Kunming mice were infected with the SS2 Y15293 strain which was isolated from a swine farm in Tianjin by intraperitoneal injection,and the model were evaluated by clinical symptoms observation,histopathological detection and bacterial isolation and identification test.The results showed that the LD50 of the SS2 Y15293 strain was 6.7×10^7 CFU/mL for the Kunming mice.The Kunming mice were attacked with one dose of LD50 of SS2 Y15293 strain,and the mice of the test group showed the spirit was depressed,the hair was inverted,and the eyes had secretions in 24 h post infection,and then showed head and neck tilt,tumbling,tremor and other neurological symptoms at 72 to 96 h post infection.The peak of death appeared at 48 to 72 h post infection.In the three repeated tests,the morbidity and mortality of mice in the experimental group were 100%,50% to 70%,and the occurrence rate of neurological symptoms was 20% to 30%.Compared with control group,the intake and body weight of the mice in test group were significantly decreased (P<0.05),and the score of clinical symptoms obviously increased (P<0.05).Histopathological examination showed that heart and lung tissues of mice in test group had different degrees of hemorrhage and inflammatory cell infiltration,and meningitis,intraventricular hemorrhage,and brain tissue were filled with inflammatory cells.Bacterial regression test results showed the bacterial colonization was found in brain,heart,liver,spleen,lung and kidney of dead mice in test group,and the morphological,staining and molecular biological characteristics of the isolates from mice of test group were consistent with the SS2 Y15293 strain.It was confirmed that the SS2 Y15293 strain could infect Kunming mice and cause the clinical symptoms.The results of this study suggested that the SS2 Y15293 strain infected Kunming mice could be used as a candidate artificial infection model for SS2.
作者
李秀丽
董志民
燕晓翠
田向学
杨春蕾
池晶晶
任卫科
李富强
谭世旭
鄢明华
LI Xiuli;DONG Zhimin;YAN Xiaocui;TIAN Xiangxue;YANG Chunlei;CHI Jingjing;REN Weike;LI Fuqiang;TAN Shixu;YAN Minghua(Tianjin Animal Husbandry and Veterinary Research Institute,Tianjin 300381,China;Tianjin Scientific Observation Experiment Station for Veterinary Medicine and Diagnosis Technology,Ministry of Agriculture and Rural Affairs,Tianjin 300381,China;Tianjin Engineering Research Center for Livestock and Poultry Health Breeding,Tianjin 300381,China)
出处
《中国畜牧兽医》
CAS
北大核心
2019年第3期840-848,共9页
China Animal Husbandry & Veterinary Medicine
基金
天津市生猪产业技术体系病毒病防控岗位项目(ITTPRS2017003)
天津市农业科技成果转化与推广项目(201301030)
天津市农业科学院基金项目(16003)
