Evaluation Of Porcine Circovirus Type2Vaccine Immune Effect

Porcine Circovirus Disease (PCVD) is general term of a number of diseases caused by Porcine Circovirus type2(PCV2).PCVD, including Postweaning multisystemic wasting syndrome (PMWS), Porcine dermatitis and nephrophathy syndrome(PDNS), Porcine respiratory disease complex(PRDC), Congenital tremor(CT) and Proliferative and necrotizing pneumonia(PNP), can mainly cause the lymph node enlargement, lymphoid depletion, which can make the function of lymph immune system depressed.In our study, to investigate the immune effect of PCV2vaccine from the different growing stages of swine of the PCV2level of antibody and positive ratio of DNA. We detected specific antibody (IgG and IgM) and DNA of PCV2of sera from different stages pigs in6pig farms (2non-vaccinated and4vaccinated) via ELIS A and PCR respectively.From the level of antibody IgG and positive ratio of PCV2, a law pattern which with the shape like a inverted parabola was observed of the data of sera from vaccinated and non-vaccinated pigs. With the age increasing, the level of antibody of IgG and positive ratio was declined to a lowest level first and then increased. The maternallylyderived antibody (MDA) of vaccinated pig herd can long to10weeks, with a low level antibody for2weeks and the time for seroconvesion of PCV2IgG is in14-18weeks; while he maternallylyderived antibody (MDA) of vaccinated pig herd can long to7weeks, with a low level antibody for1week. The time for seroconvesion of PCV2IgG is in the12-16weeks.From the aspect of the level of PCV2IgM and positive ratio, the two were all with a low value nomatter vaccinated and non-vaccinated pig herd (S/P valueand the positive ratio is under0.4and40%respectively). The level of PCV2IgM antibody and positive ratio of growing pig herd is higher than the nursy pig herd. The time of PCV2IgM antibody and positive ratio increasing is different between vaccinated (12th weeks old) and non-vaccinated (10th weeks) pig herd.From the point of PCR positive ratio of PCV2DNA, there existed some relationship between antibody and DNA, considering the production of every single farm. There is no obviously difference of detection ratio of PCV2DNA in sera between vaccinated and non-vaccinated pig herd. The possibly reason is the difference of pig healthy and number of specimen in various farm.To sum up,the rate of descent of MDA can be reduced after sows was vaccinated and the infectious time of PCV2was put off.Since the chance to spread the virus of herd was lessen and the density of PCV2in pig herd and enviroment was depressed. So the PCVD was prevented in some extend.