Detection Of PCV-2by PCR In Eleven Pig Farms In Guangzhong Region Of Shaanxi Province And Evaluation Of Csf Immune Antibody Level

With the development of modern animal husbandry,the scale andintensification level of swine husbandry become higher in China. The diseasesalso show increasing and complexes in swine population, causing more seriousproblem in disease prevention and control, this situation also is a major problemin swine husbandry all of the world. The pathogen causing immunosuppressivein infected swine is the main reason, which could cause no antibody or low levelantibody in immunized swine and more difficulties in disease prevention andcontrol. The immunosuppressive pathogen not only cause the primary diseasesleading to onset disease in swine population, but also damage the immunesystem leading to no or low immune reaction in vaccinated swine, more seriousis the secondary infection and mixed infection will increase in swine causingdisease outbreaks. The main immunosuppressive pathogen include porcinecircovirus type2(PCV-2), porcine reproductive and respiratory syndrome virus (PRRSV), pseudorabies virus (PRV), porcine parvovirus (PPV) and classicalswine fever virus (CSFV).The PCV-2,PRRSV,PRV and PPV were detected in320blood samplescollected in40-50day-old piglets of6counties scale swine farms of Shaanxiprovince by established polymease chain reaction (PCR)and (Reversetranscription polymease chain reaction). The PCV-2were checked in all6counties swine farms. PRV,PPV and PCV-2were detecred in a same swine andPPV,PCV-2were detected in3swines at the same time. No PRRSV wasdetected in all blood samples.A detective rate of PCV-2was25.00%~93.33%in different counties andswine farms, the positive rate of PCV-2was53.81%. The higher PCV-2averagepositive rate was66.67%(40/60) in swine sample of Xingping county, the lowerPCV-2avrage positive rate was25.00%(10/40) in Yangling county. A differentPCV-2positive was found in samples collected in a same county, the lowestpositive was25.00%(5/20), but the highest positive rate was93.33%(28/30).In order to further analyse the influence in antibody titre of classical swinefever (CSF)in vaccinated swine infected with PCV-2. The CSF antibody titrewas tested in169serum samples infected with PCV-2and151serum sampleswith PCV-2-free by enzyme linked immunosorbent assay(ELISA). The resultsshowed that the antibody qualified rate of CSF was48.52%(82/169) in PCV-2-infected swine sera and77.48%(117/151)，significantly higher than thePCV-2-positive pigs（P＜0.05） The results showed that the antibody qualifiedrate of CSF was significantly effected in PCV-2swine.