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Infectious bursal disease caused by infectious bursal disease virus and is a highly contagious immosuppression . In recent years,the disease had been brought under control to some extent because of people’s gradual understanding of IBD.However,in the late of 1980s, the more virulent IBDV have emerged, which makes it very difficult to vaccineation.So far,vvIBDV has broken out in many regions of china that result of vaccine failure to IBD,so, it is an imperative thing to find a more rational and effdctive way of the prevention and treatment of IBD.At present,the disease of virual infection have no effective drug to treat, to control it, the primary means is to use vaccines.Therefore,the immune prevention key is to find popular IBD strains. This experiment based on the prevalence condition of IBDV in Shandong province,some field strains of IBDV were isolated from many regions in Shandong province,the immune effect prove that the field strain has good immunogenicity and has the protection of chickens against vaccine stain virulent. This test comprises three parts:Part I:Isolation and identification of field IBDVIn the experiment,we obtained 829 suspected material from the clinical symptoms of chickens in Shandong province ,according to the epidemiology and clinic symptom of infected chickens,AGID and reversion susceptible chickens.Firstly, select the 118 positive disease material, secondly select pure IBD material Exogenous virus detection then determine their purity and named it CPVThe strain of clinical symptoms、typical pathological anatomy changes, fast onset, short course, a high fatality rate, are very-virulent strain. PartⅡ:The field IBDV subculturedThere are two main means to culture IBDV: embryo and CEF,the result of CP subculture indicated that CP can not be adapted to CEF ,it take a long time to obtain a cell-addpted virus.So this study still focus on cultivating embryo for CP subcultured in order to optimize embryo culturing, so that the method is more suitable for the cultivation of IBDV.The literature shows that the titer of IBDV is higher in CAM and liver than in AF,in the course of the experiment found that embryo heaptomegaly, lung、kidney and yolk sac bleeding severely,then the embryos and the yolk in the viral titer is not less than CAM?The experimental compareison show that the virus titer of the mixture of CAM、embryo、egg yolk and AF was not lower than the CAM,,during the course of the chick embryo culture,the cell passage of CPV and appeared the CPE at the eighth as CCP.PartⅢ: The IBDV strain from Shandong vaccine,inactiveated preparation and applicationIn this study ,the CP and the BJQ902 vaccine immune 21-day-old SPF chickens, through detection of anybody titers and poisn attach protection provedthat the antibody titer of CP vaccine is higher than the BJQ902 vaccine in the second week, the anybody titers of CP vaccine is tidy, the CP vaccine can attack of the CP and the BJQ902 infectious and has a higher rate of protection. It showed that immunization of CP vaccine not only produces high and tidy antibody, but also has good cross-strain protective effect.
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