Monitoring Of Serum Antibody Against CSFV,PRRSV,PRV,PCV2 In Some Regions Of Hunan Province

In recent years,the epidemic situations of various swine virus-associated diseases are becoming more complex in China.Several major diseases causing by classical swine fever virus(CSFV),porcine reproductive and respiratory syndrome virus(PRRSV),porcine pseudorabies virus(PRV)and porcine circovirus type 2(PCV2)are threatening the health,stable and rapid development of China's pig industry.In order to investigate the epidemics of these four virus-associated diseases above in Hunan province and the efficacies of vaccine immunizations,serological investigations on these four viruses were performed in eight cities of Hunan province from September 2017 to September 2018.Furthermore,to provide a basis for further development of more scientific preventions and control measures.This study conducted a serological investigation on these four major infectious diseases among various growth stages of pigs.In order to understand the serological infection situation of CSFV,PRRSV and PRV in Hunan province,the samples of piglets and fattening pigs without CSFV vaccination in Hunan province are detected with ELISA.The result shows that maternal antibody in piglets decreases gradually with increase of piglets' age.And there is no CSFV infection on fattening pigs.636 serum samples without PRRSV vaccine are detected with ELISA,and the average positive rate is 48.1%.It shows that PRRS may appear in various growth stages in these regions of Hunan province and highest positive rate is 94.3% in Yiyang and the lowest is 37.4% in Changde.The highest positive rate in different growth stages is 80% for boars,and the lowest is 31.1% for fattening pigs.The positive rates of PRV gE antibody is 22.3% by detecting 1523 serum samples.The area with the most serious infection is in Shaoyang(positive rate 48.8%)and the lowest rate is 0% in Yiyang.The highest positive rate of PRV gE among various growth stages is 27.4% for piglets,and the lowest is 4.3% for fattening pigs.All the above three viruses caused clinic infections to some extents in Hunan province.Vaccination efficacies against CSFV,PRRSV,PRV and PCV2 have also been studied in Hunan province,the positive rates of CSFV antibody is 82.2% by detecting 1320 serum samples in Hunan province,and the dispersion is 32%.The immune effect in Yongzhou was best with the positive rate is 96.6%.The immune efficacy was not uniform at different growth stages,the highest positive rate is 92.6% in boars,and the lowest is 50.3% in nursery pigs.The positive rates of PRRSV antibody is 84.4% by detecting 935 serum samples.The highest positive rate is 95.8% in Yiyang with the best vaccination efficacy,and the lowest is 74% in Hengyang.Among various growth stages,the positive rate of sows is highest(88.1%)and the immune efficacy reached the standard.The lowest rate is 28.6% in piglets,which indicate the poor vaccination efficacy.The positive rate of PRV gB antibody is 88.5% by detecting 1057 serum samples.The highest positive rate is 100% in Yongzhou with the best vaccination efficacy,and the lowest is 75.9% in Chenzhou.At various growth stages,the positive rate of piglets is 99.3% with the best vaccination efficacy.The positive rate of fattening pigs is the lowest(65.8%).The positive rates of PCV2 antibody is 94.2% by detecting 753 serum samples.The vaccination efficacies in Yueyang,Yongzhou,Changsha and Yiyang are the best among these areas.Among various growth stages,the positive rate of piglets is 99% with the best vaccination efficacy.The positive rate of fattening pigs is 57.1% with poor vaccination efficacy.