Research And Generalization Of Prevention And Control Technology Of Swine "High Fever" In Taizhou

The prevention and control of swine "high fever" have become a tremendous task for the animal epidemic prevention in our city. Due to the complexity of causes of swine "high fever", as well as the regional diversity, the pathogeny in our city is different from others. This research is in the interest of pertinently work so as to improve the prevention and control of swine "high fever", effectively reduce the case fatality rate, and ensure the development of swine productions. The purpose of this study is to investigate the causes and epidemiology characteristics of swine "high fever", which will contribute to improve the pertinency and the maneuverability of the prevention and control of swine "high fever".1Preliminary Study on the Cause of swine "high fever"To investigate the causes of swine "high fever",30cases of swine "high fever" were detected by PCR, bacterial culture, and blood smearing. The results showed that, in spleen and lymphaden, the positive rate of Pasteurella is9.7%(7/72, positive numbers/sample numbers, similarly hereinafter), and the positive rate of Streptococcus suis is16.7%(12/72). The positive rate of Eperythrozoon and Toxoplasma were25%(9/36) and6.3%(2/32), respectively. The positive rate of PCV-2, PRRSV and CSFV were47.2%(34/72),43.1%(31/72) and29.2%(21/72). The data indicated that, swine "high fever" was caused by mixed or secondary infection, and the major pathogens are PCV-2, PRRSV and CSFV.2Immunity Research of Foot-and-Mouth Disease, CSF and PRRS (Inactivated Vaccine)To study the influences of immune programmes on immune efficacy of inactivated vaccines, thirty post-weaning piglets were randomly divided into six groups (n=5). Group1-5are the test groups, and the sixth group is control group injected with physiological saline. All the5test groups were treated with different immune programmes. This experiment last for16weeks, and the blood samples were gathered, at0,14,21,28,35,42,56,63,70,77,84,98and112day, respectively, for the antibody detection. The results showed that, the immunization of CSF should be doubled due to high level of maternal antibody, and the immunity dose should be properly intensified. Therefore, the level of maternal antibody should be detected before the immunization, and inject the vaccines when the level of antibody approximates to the ritical value. The immune efficacy of the FMD type O synthesized peptide vaccine is better than that of the FMD type O vaccine (OS/99). No notable differences were observed between inject PRRS vaccine alone and inject PRRS, CSF and FMD vaccines at point of division, simultaneously. According to the results, as the age of first immunization has a certain influence to the immune efficacy, the first immunization of PRRS should be taken at age of28-35days.3Immunity Research of Foot-and-Mouth Disease, CSF and PRRS (Attenuated Vaccine)To investigate the impacts of immune programmes on immune efficacy of attenuated vaccines, forty post-weaning piglets were randomly divided into four groups (n=10). Group1-3are the test groups, and the fourth group is control group injected with physiological saline. Piglets in the first test group were injected with PRRS, CSF and FMD vaccines at point of division, simultaneously. The second group was injected with PRRS vaccine at21days-old, and injected with CSF and FMD vaccines7days later. In the third group, CSF vaccine was injected when piglets were21days-old, then PRRS and FMD vaccines were injected after one week. This experiment last for14weeks, and the blood samples were gathered, when the piglets were21,35,42,49,56,63,70,77,84,91,98and119days-old, respectively, for the antibody detection. The results showed that, the level of CSF and PRRS antibodies were significantly decreased at63and70days-old, respectively; whenas the level of FMD antibody has no notable difference. In the second group, CSF antibody reached to the positive level one week after immunization; FMD antibody had comparatively large variation; meanwhile PRRS vaccine had preferable protective effects. In the third group, PRRS antibody attain the positive level one week after immunization. These results suggest that, the immune programme adopted in the first group is not recommended in actual production. The injection of PRRS and CSF, with an interval of7days, can provide a solid protection for piglets.4Investigation of Immune Efficacy of Swine VaccinesTo appraise the immune efficacy of several major infectious diseases, the antibody of FMD, CSF and PRRS were detected. The samples, useing for analysis of global level of antibody protection, were gathered form pig keepers and hoggery with different scale. The results shown that, the eligible rate of FMD type O antibody is95%. The eligible rate of CSF vaccine is irregular, and its variation amplitude of hoggeries was large. The immune efficacy of PRRS is solid.5Integration of Synthetic Prevention and Control TechnologyThe integration of synthetic prevention and control technology is beneficial to reduce the lost of pig keepers. Along with the spread of the synthetic technology, the incidence and mortality of swine diseases were decreased significantly. The direct economic loss reduced about200millions yuan. Furthermore, the implementation of synthetic technology eliminated the fear of pig keepers, and promoted development of swine productions.