Isolation And Identification Of Bovine Enterovirus And Development Of Bivalent Inactivated Vaccine

Bovine Enteroviruses(BEV)can cause diseases of digestive system and respiratory system in cattle,Even affect the reproductive function of cattle.After the first report in the late 1960s,the disease has spread around the world,which has brought great impact on cattle industry in various countries,and the economic losses caused by it are even more inestimable.At present,countries around the world are actively studying the detection and prevention of the disease.In this experiment,cattle nose swabs and fecal swabs with diseases of digestive system and respiratory system were collected from a farm in Inner Mongolia and inoculated into MDBK cells.After PCR detection,plaque cloning and purification,three strains of BEV were successfully isolated.The phylogenetic tree was constructed by sequence determination and the type of the isolated virus was finally determined.2 strains belonged to type E and 1 strain belonged to type F.All the samples were taken from the same pasture,indicating that there may be BEV-E and BEV-F enterovirus infection in the same farm.The results of this experiment provide an important basis for the immune prevention of BEV in the farm in the future.In this study,the isolated BEV strains were used to explore different mouse strains and different infection routes,and finally an infection model of ICR mice was established by intragastric administration as the challenge method,and the infected mice showed different clinical symptoms.The liver,small intestine,lung and spleen showed different pathological changes after dissection.PCR detection of these tissues can detect BEV specific bands,and successfully establish BEV animal infection model,which provides a lot of basis for the establishment of animal model of BEV in the future.In this experiment,the virus content of 1×10^8.3TCID₅₀/m L was prepared by using the isolated BEV-E and BEV-F strains,and the immunological test was carried out on ICR mice with the immunological dose of 200?L/mouse.After immunization with bovine enterovirus bivalent inactivated vaccine,the neutralizing antibody against E strain reached 1:2^6.6,and the neutralizing antibody against F strain reached 1:2^6.8.After 28 days of immunization,the mice in the immune group and the control group were attacked.The results of virus isolation in the immune group were negative,while the results of virus isolation in the control group were positive,indicating that the bovine enterovirus bivalent inactivated vaccine has a good immune protection effect on ICR mice,which lays a certain foundation for the development of BEV vaccine in the future.