Epidemiological Investigation Of Pseudorabies Virus In Parts Of China From 2015 To 2017 And Study On PRV Immune Enhancement

To investigate the prevalence of pseudorabies virus infection in parts region of China from 2015 to 2017,9 447 pig serum samples were collected from 19 provinces in China for pseudorabies virus gE antibody detection.Finally,5 699 positive samples were detected,and the positive rate was 60.33%.To investigate the correlationship between pseudorabies virus gE antibody and the quarter,the detection results were categorized according to different quarters.The results showed that from the first quarter of 2015 to the fourth quarter of 2017,the positive rate of pseudorabies wild-type gE antibody was gradually increasing.The positive rate of gE antibody at the first quarter of 2015 was 49.86%.By the last quarter of 2017,it had risen to 81.43%.The increase trend is very significant.To investigate the correlationship between pseudorabies virus gE antibodies and different age groups of pigs,the detection results were categorized according to the age of the pigs.The results showed that the highest gE antibody positive rate was 73.19%in newbron piglets,and the lowest was 50.27%in fattening pigs.These data indicate that high-age pigs have higher tolerance to PRV infection compared to low-age pigs.To investigate the correlationship between pseudorabies virus gE antibodies and different regions,the detection results were categorized according to the area of sample source.The results showed that the highest positive rate of gE antibody was found in Henan Province,which was 75.78%,and the positive rate of gE antibody in Shaanxi Province was the lowest,which was 54.31%.In order to study whether the transfer factor and microecological agent can enhance the immune response to the vaccine,we added the transfer factor or microecological preparation before and after immunization with PRV Bartha K61 attenuated vaccine,and determined the PRV GB antibody in pigs.The contents of CD4~+and CD8~+T cells and the concentrations of cytokines such as IL-2,TNF-?and IFN-?in blood.Only transfer factor could significantly increase the level of PRV gB antibody in pigs after immunization.The effect of two kinds of immunopotentiators on the of CD4~+cells,CD8~+cells,IL-2,TNF-?,IFN-?were not significant.In order to evaluate the immune effect of an inactivated vaccine against a mutant pseudorabies virus strain,the vaccine was subjected to a number of immunization test,comparison with attenuated vaccine immunization test,Comparison with inactivated vaccine immunization test and clinical application test.Comparison of the number immunization experiments showed that two immunizations performed better than one immunization.The comparison with attenuated vaccine immunization test showed that the group immunized twice inactivated vaccine had better gB antibody dispersion and a lower rate of wild virus conversion.The comparison test of pseudorabies inactivated vaccine of different strains showed that the inactivated vaccine was better than the gB antibody level,the gB antibody dispersion and the average titer of gB antibody after immunization,which were better than those of the pseudorabies inactivated vaccine group and the pseudorabies inactivated vaccine group of the E A strain of Min A,and the level of gE antibody was significantly lower than that of the other two groups.Clinical trials showed that the gB antibody was steadily increased after the pigs immunized the inactivated vaccine.The gE antibody rapidly decreased with increasing age and turned completely negative at the late stage of fattening.These tests show that the vaccine evaluated has a nice immune effect and superior clinical application value.