Researches On Molecular Epidemiology Of The Infectious Bronchitis Virus (IBV) Isolated In China

In this paper, the pathogen and molecular epidemiology relationships between IBV strains isolated in china were researched based on their gene and protein sequence difference. This study includes: 1. Isolation and identification of IBV local strains of china: 48 IBV isolates from 20 provinces of China have been done, including Shanghai, Tianjing, Hebei, Inner mongolia, Jilin,, Heilongjiang, jiangsu, zhejiang, Fujian, Jiangxi, Shandong, Henan, Guangdong, Guangxi, Sichuan, Gansu, Xinjiang, Anhui, Guizhou and Shanxi 2. A series of identification methods for IBV were established, including chicken embryo dwarf test, Dot-ELISA and Dot-blot. 3. The RT-PCR method of IBV was established for amplifying the whole S 1 gene. The method is stable and repeatable in amplifying RNA from IBV strains and virus from other source. 4. The complete Si gene of 10 IBV isolates were amplified, 7 of them had been cloned and sequenced, 6 sequenced Si genes were registered in GenBank. 3 N genes were amplified from 3 IBV isolates, One of them had been sequenced. 5. According to the analyzed result of gene and amino acid sequences of IBV isolates in China, the isolates were divided into 3 groups that probably indicate the different origins of IBV in china. The strains in- group I, have the nearest relationships with the traditional IBV vaccine strain, 11120 and M41, they might be the varieties of vaccine strain. Strains in group II are separate, they have little sequences identity with those in group I and other reference strains, they might be the field strains in China or come from other countries in recent years. Strains in group III have close relationships with vaccine strain too, but their identities are not as near as those in group I, they might be the recombinant of field strains with vaccine strains. 4 There are no evident relationships among geography, time spending and strain ecologies, there are no evident relationships with identity and cell ingratiating either, A little variations in key region of proteins might arouse phenotype variation of the disease...