| Classical swine fever (Hog Cholera,HC or Classical Swine Fever,CSF) is a highly contagious disease in pigs caused by the Classical Swine Fever virus. The main characteristics of CSF is bleeding and hemorrhagic, and it caused abortion of pregnant sows, fetal aberration, chronic nutritional consumption, immune system injury, such as reduction of lymphocytes and thrombocytopenia, clinical manifestations secondary or concurrent such as bacterial infection or other virus infection, acute or chronic, and is a great danger of infectious diseases to pigs, the disease must be reported by the Office International des Epizooties (OIE).China has been the use of classical swine fever vaccine to prevent and control classical swine fever, and it achieves good results in reducing Classical swine fever incidence and infection. However, classical swine fever still occurs from time to time in recent years in the actual production, especially atypical Classical swine fever in piglets.In addition to the inappropriate first immune time of classical swine fever vaccine and interference of maternal antibodies of occurrence of classical swine fever in piglets,the practical effect of immunization is very important as a factor. At the same time, the assessment of the quality of classical swine fever vaccine is also an important prerequisite for classical swine fever immunization.This research consists of three parts as follows:Partâ… : Blocking ELISA test methods is adopted to check out different day-old piglets of classical swine fever maternal antibodies. The result showed that the titers of the maternal antibodies in piglets were zero before suckle, arrived the highest level in the first day, and then slowly declined. The average 30-day-old antibodies level is still above the level of protection, Therefore the first immune time which commonly used in the past 20-day-old should be free to postpone. According to antibody titers of 20-day-old piglets weaned and antibody titers of 30-day-old piglets, half-life of Hog cholera maternal antibody in piglets is 6.8d.Partâ…¡: Blocking ELISA test methods is adopted to check out immune effects of three different classical swine fever immunization procedure on piglets. Immune procedure are (0,35,60),(0,60) and (35,60) respectively.The results of CSF antibodies by different vaccines immunization show that the average rate of piglets in differences blocking antibody are extremely significant (P < 0.01),so the development of appropriate immunization procedures should be based on the effect of classical swine fever vaccine.Partâ…¢: Fluorescence quantitative RT-PCR and Blocking ELISA testing methods are adopted to detect the content of virus and exogenous virus (BVDV) for classical swine fever respectively. The evaluation results of titer of classical swine fever vaccine by fluorescence quantitative RT-PCR show that Virus content of 15 kinds of classical swine fever vaccine are very different, from 0.87×106 to 38.45×106 virus particles/mL. This method is simple,fast,accurate quantitative,good reproducibility, and a large number of samples can be quantitatively detected in a short time. Thus, it is feasible as titer assessment of classical swine fever vaccine. However, it demands operator proficiency strictly; The test results of BVDV antigen in Classical swine fever vaccine show that three kinds of spleen and lymph vaccine do not contain BVDV antigen, and there are six kinds of testing positive for BVDV antigen in twelve kinds of cell vaccine, contamination rate was 50%. Therefore, the detection of BVDV antigen in classical swine fever vaccine is an important indicator of vaccine whether qualified or not. In short, the quality of the assessment of classical swine fever vaccine is an important prerequisite for classical swine fever immunization. |
