Study Of Combined Attenuated Vaccine Against Newcastle Disease, Infectious Bronchitis Disease And Infectious Bursal Disease

Newcastle Disease(ND) Virus Lasota strain and Infectious Bronchitis(IB) Virus H₁₂₀(or H₅₂) strain were inoculated into chicken embryos and the allantoic fluid was collected. Infectious Bursal Disease(IBD) Virus BJ₈₃₆ strain was inoculated into chicken embryo cells and the cultivate fluid was collected. Mixed the allantoic fluid and the cultivate fluid in appropriate proportion. The attempted triplex vaccine against ND,IB and IBD was prepared. The tests of 3 continuous batches of the triplex vaccine showed: It is reliable safety, exact immune effect ,simple and convenient administration. 15day old chickens showed no bad effect past inoculation with fifteen times normal dose. The chickens had immunity 7 days past inoculation at a normal dose by injection under skin in neck. The chickens obtained 100% protection rate against ND,IB and IBD, when they were challenged with the standard virulent. 15 days past inoculation. The immune protection period of the triplex was 30 days at least. The store period of the triplex vaccine was one year at -25℃.