Preservation And Control Of Infectious Bronchitis Virusesisolated From Sichuan Province

Infectious bronchitis that caused by Infectious bronchitis virus, is an acute, highly contagious, virus disease in respiratory tract and genital tract. It lead to the decrease of egg production or the declined quality of these eggs.It also causes that commercial broiler’s weight gain and the forage’s remuneration decreases, and that case fatality rate of the poultry increases. So Infectious bronchitis causes great economic losses. It makes the immunoprophylaxis complex and the prevention cost rises that the highly contagious character of IB and the complexity of IBV’s serotype.Thus how to control IB counts much economic significance.In this study,37strain of IBV S1gene strains were isolated from Sichuan district were sequenced. and molecular epidemiology relation were analyzed. Further Studies on the application of live vaccine combined with inactivated vaccine is in progress, research on the Detecting under the immunologic procedures antibody titer of different ages breeding bird and maternal antibody level of different at laying period in order to establish an effective vaccine screening and assessment method.(1)37field IBV strains acquisition during2009to2010were isolated and identified. Epidemiological analysis shows that avian infectious bronchitis is more easier attack in spring and winter, among20days of age, respiratory strain is more easier happen and after40days of age, mainly kidney type.(2)37strain of IBV S1gene strains were sequenced. the result of sequences alignment of S1gene occurred base mutation、insertion、deletion, the performance is that different nucleotides and coded amino acid number of S1gene.Of the37isolates strains have three cracking site base sequence.(3) Phylogenetic analysising37isolates and33reference strains S1gene with MEGA4.0analysis software, Cluster from the six major genotypes (genotypes Ⅰ-Ⅵ),14IBV strains clustering for CHI in the37isolates,2IBV strains clustering for CHⅡ,6IBV strains clustering for CHIⅡ,1IBV strains clustering for CHIV,14IBV strains clustering for CHV. The similarity of all separation between plant nucleotide and amino acids were77.6-99.6%and74.4-99.4%.(4) After the pre-branch twice immunization by IB attenuated in two weeks,the antibody of chicken has a certain rised(1200-1500). Combine with two oil seeps immunization in back-up stage(5weeks to15weeks), antibody titers can be increased to5000. Vaccine immuned in laying period in cycles, Strengthen immuned oil seepage around38weeks enable the level of chicken antibody maintain in5000-12000titer. Chicks’maternal antibody levels can be maintained in the range of2000-5000titer.(5) There remains no specific treatment to infectious bronchitis up till now. Establishing perfect comprehensive measure,such as biological systems is necessary.