الفهرس | Only 14 pages are availabe for public view |
Abstract Propagation of the BYD virus ( Iman strain ) genotype I in madine derby bovine kidny cell culture ( MDBK) and used BAI for inactivation of BYD virus at 0.02% concentration for 6 hours at 37°c . Add 20 % alhydrogel as adjuvant and evaluated according to code Federal regula tion (1997) as follow : 1- Pu rity tests: Ind icated the purity of vacci nes from extraneous pathogens. 2- Safety test: Safety tests occur in 25 mice, 4 Guinea pigs and 2 calves proved that the vaccine the vaccine is safe. 3- Potency and challenge exposu re tests : Eight calves divided into two groups Grou p 1: Each calf was immunized twice with intra muscular 5 ml of prepared vaccine 2 week a parts . This group was divided into two sub group 2 calves each as follows subgroup A. This group used for determination of antibody response against prepared vaccine. The humoral immune response against prepared vaccine more than the permissible limit of Judgement of vaccine, in laboratory according to the code of federal regulation 1997 minimum protective titer 1: 8 using SNT. Subgrou p B: The other two calves were challenged at 28 days post injection of the second dose of vaccination with pathogenic virulent Imain strain of BVD. No clinical finding through out the challenged period and the immune response capable for protecti ng calves against experimental infection using virulent BVD strain. group 2: This group also 4 calves left as control (not vaccinated) and divided also into 2 subgroups: i) Positive infected control calves was infected by l O ml of virulent virus, appear clinical signs which are rise of body temperature 40.4 dullness , off food , serous nasal discharge and faeces became moisten , thesis symptoms lasted up to the 1oth days after which complete recovery occurred . ii) The other two calves were left as non-infected and non-vaccinated control calves. III- Evaluation of prepared vaccine under field condition: The test was done on pregnant cows at last third of gestation in Amine Mobarak farm at Kafr El- Sheikh govemorate . Twenty apparently healthy pregnant cow dams were vaccinated by intramuscular injection of 5 ml of prepared vaccine, 2 weeks a part at late stage of pregnancy (1-3 months before delivery) and five pregnant cows were left as unvaccinated control. The antibody levels were estimated by using SNT and ELISA techniques for both dams and off- springs . Dams gave off springs immunized with BYD antibody withi n the protecti ve level up to 5 and 7 months of age. Accordi ng to the time of delivery post vacci nation. |