›› 2019, Vol. 46 ›› Issue (3): 840-848.doi: 10.16431/j.cnki.1671-7236.2019.03.024

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Establishment and Evaluation of the Artificial Infection Model of Streptococcus suis Type 2 in Kunming Mice

LI Xiuli1,2,3, DONG Zhimin1,2,3, YAN Xiaocui1,2,3, TIAN Xiangxue1,2,3, YANG Chunlei1,2,3, CHI Jingjing1,2,3, REN Weike1,2, LI Fuqiang1,2,3, TAN Shixu1,2, YAN Minghua1,2,3   

  1. 1. Tianjin Animal Husbandry and Veterinary Research Institute, Tianjin 300381, China;
    2. Tianjin Scientific Observation Experiment Station for Veterinary Medicine and Diagnosis Technology, Ministry of Agriculture and Rural Affairs, Tianjin 300381, China;
    3. Tianjin Engineering Research Center for Livestock and Poultry Health Breeding, Tianjin 300381, China
  • Received:2018-09-29 Online:2019-03-20 Published:2019-03-20

PDF (PC)

191

Abstract:

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 6.7×107 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.

Key words: Streptococcus suis type 2 (SS2); Kunming mice; artificial infection model

CLC Number: