The Research And Application Of General Control Measures Of Atypical CSF For Large Scale Pig Farms

Hog Cholera(HC), or Classical Swine Fever (CSF), is a highly contact infectious disease, caused by Swine Fever Virus (CSFV). CSF was concerned by all countries in the world because it caused huge economic losses. In China the prevalence and development of CSF showed new change because of various aspects of affect. Atypical CSF emerged and showed the trend of the spread and proliferation in some regions. Atypical CSF means the pathogen is CSFV, but the epidemiology, clinical symptoms, pathological changes differ large with Classical Swine Fever. This research detected the CSF antigen and antibody of part of large scale pig farms in Henan. The general control measures of atypical CSF were formulated and applied in some farms according to the test results.1. Investigation of atypical CSF in HenanThe prevalence strate, vccine, immune programme, morbidity and mortality rate, treatment and result were mastered via site investigating, blooding random the pigs of different growth stage and detecting the CSF antigen with ELISA. The results showed that the positive ratio of sow and boar was 15.58%, 13.75% of cradling piglets, 13.51% of finishing pigs and 11.11% of nursing piglets. The average positive ratio of the groups was 13.33%.2. Detection of CSF antiboy level of different stage groupsThe antibody level was detected with indirect hemagglutination (IHA) assay. The results showed that the CSF antibody of large scale pig farms in henan was relatively high. The antibody of sow and boar group was highest and the positive ratio was 91.54%, That of cradling piglets 87.95%, 79.69% of finishing pigs and 76.67% of nursing piglets. The average positive ratio of the groups was 80.96%.3. Resaerch of the dynamics of CSF maternal antibody of pigletsThe dynamics of CSF maternal antibody of piglets was studied by IHA assay. was high at 1-28 day after birth. The antibody was highest at 7-14 day and the protection ratio was 100%. The antibody begain to reduce since 14 day and reduced to 55% at 42 day.4. Affect of piglets antibody by ultra-pre immunityThe affect of piglets antibody by ultra-pre immunity was studied by blocking ELISA assay.The results showed that the antibody of ultra-pre immunity group and non-ultra-pre immunity group was close at 20 day-old. The antibody of ultra-pre immunity group rised faster obviously than the non-ultra-pre immunity group. The ultra-pre immunity could stimulate production of CSF anthbody better.5. Affect of piglets antibody by different immune programmeThe affect of to piglets antibody by different immune programme was studied by blocking ELISA assay. The results showed that the effect of 0-40-100 programme was better than that of 20-60 day-old.6. Formulation and applicaton of general control measures of atypical CSFThe general control measures of atypical CSF were formulated and applied in 5 farms according to the detected results and the local conditions. The results showed that the positive ratio reduced 5% nearly , the protection rate of antibody raised 11% and the morbidity rate of piglets reduced 4.2%,compare before and after purifucation. These measures was very good and provided theoretical basis and guidance for prevention and control of atypical CSF in pig production.