Effect Of Application Of ELISA In The Prevention And Control Of Classical Swine Fever In Intensive Pig Farm

Abstract:Hog Cholera(HC),or Classical Swine Fever(CSF), is a highly contact infectious disease, caused by classical swine fever virus by classical swine fever virus of the Flaviviridae. It can cause fever and a highly contagious and fatal contagious infectious diseases. In recent years, under the influence of various factors, the characteristics of Chinese classical swine fever epidemic shows new changes, showing and spreading the trend in many regions. CSF emerged and showed the trend of the spread and proliferation in some regions.This study tested the CSF antigen and antibody level of several large scale pig farms applied by ELISA assay in Fujian. According to the test results,we formulated the comprehensive control measures of CSF and popularize in some farms.1. Determination of CSF antigen in part of the large-scale pig farm in Fujian.In April to December2011, Collected different stages of swine whole blood samples of628copies in45large-scale pig farms around the city in Fujian,135copies of the production of sows, nursing piglets152,166cradling piglets,175finishing pigs. Classical swine fever virus antigen (CSFV-Ag) ELISA test kit to detect swine fever antigen. The results showed that the positive ratio of breeding pigs was18.52%,15.66%of cradling piglets,13.71%of fattening pigs and11.84%of nursing piglets. The average positive ratio of the groups was14.81%.2. Detection of CSF antibody level of breeding pigs in part of the large-scale pig farm in Fujian.In June2011to January2012,4297blood samples of breeding pigs and replacement pigs were collected from122large-scale pig farms and the serum was separated from blood. Classical swine fever virus antibody (CSFV-Ab) ELISA test kit to detect swine fever antibody. The results showed that the positive ratio for antibody of breeding pigs was48.6%;the positive ratio for antibody of replacement pigs was52.6%.3. Detection of the dynamics of CSF maternal antibody of piglets10female breeding pigs qualified by swine fever antibody detection were chosen from a large-scale pig farms in Nanping. Randomly selected total of20piglets born of per sow weaning25day, no injection swine fever vaccine, respectively in1-day-old,5-day-old,10-day-old,15-day-old,20-day-old,25-day-old,30-day-old,35-day-old,40-day-old with (CSFV-Ab) ELISA test kit for detection of classical swine fever antibody levels to observe the growth and decline of maternal antibodies law. The results show that:5to10-day-old suckling piglets serum antibody positive rate of100%for the highest. Antibody levels began to decrease after15days of age, and to protect critical value (80%positive rate) to about25days of age, and40days of age has been reduced to5%.4. Affect of piglets antibody by different CSF vaccine immune programme12sows were randomly divided into Ⅰ,Ⅱ two groups chosen from a large-scale pig farms in Fuqing. Each group was6sows. Piglets of group Ⅰ ultra-pre inject the hog cholera rabbit spleen lymph node vaccine at0day-old,40days and100days booster immunization with the same vaccine and collected blood samples at the age of20days,40days,70days,100days,130days; piglets of group Ⅱ inject the hog cholera rabbit spleen lymph node vaccine at25days of age for first immunization booster immunization with the same vaccine at60day and collected blood samples at the age of25days,60days,80days,100days,130days. The results showed that the two immunization program test farms can meet the requirements for the prevention of classical swine fever virus.5. Applicaton and formulation of comprehensive control measures of CSFBased on the above studies, combined with the actual local situation, we formulated a comprehensive control measures of CSF applied in pig farms we selected. It shows that swine fever antigen positive ratio dropped4.4%, the antibody protection rate increased to9.4%, mortality of piglets reduced3.2%after the control measures works.