Establish A Differential Diagnostic Method For PRRSV And Construction And Analyzed The Genome Library Of Sichuan Strain

Porcine Reproductive and Respiratory Syndrome is caused by Porcine reproductive and respiratory syndrome virus (PRRSV).The infectious diseases is spreading rapidly in global swine-raising countries since it was reported in 1987. In 1991, the virus was cultured successfully by using Porcine alveolar macrophages.At the same time, the disease was first reported in Tai Wan, and it was also reported in mainland of China in 1995;in 1996, the pathogen was separated and diagnosed as American type PRRSV. In part ares of China,swines appeared with "high fever syndrome" whose characteristic is high morbidity, high mortality, and it was discovered that the syndrome is caused by PRRSV mutant by pathogeny survey and analysis and cause significant economic losses to our swine industry.In this study,the effective differential diagnosis method separating PRRSV from PRRSV mutant has been established for the prevention and control of the disease. Meanwhile,the genomic library of PRRSV CH-1R strain has been contructed and analysed by bioinformatics, laying foundation for the study of relationship between genetic variation and irulence. Some research results of the study obtained has been listed:1. Compared NSP2 squence of PRRSV mutant with PRRSV by DNAstar. RT-PCR method has been established successfully and has the ability to simultaneously detect PRRSV and PRRSV mutant with three specific primers for detection according to the different conservative areas. And the established method has been used for detecting 100 samples,in results,26 PRRSV mutant and 8 PRRSV were detected, positie was 26% and 8% respectively.2. PRRSV separated from different areas have been seqenced for constructing genomic library which is important to explore the relationship bewteen viral mutation rules and structure and function of viruses. Viral structure change often cuases differences of biological characteristics and pathogenic, and viral structure change is decided with genome differences.5 pair primers designed at conservative areas of PRRSV complete genome (Accession Number:NC₀06151) reference to GenBank by sequence alignment method was used for cloning genome sequence of PRRSV SCS strains, and cDNA ends rapid amplification method was used for amplificating 5'and 3'sequence, in results,PRRSV SCS strains complete genome sequence has been obtained.It is builted the foundation for analysis genetic characteristics of PRRSV among different areas in China.3. Genetic evolution relationship among PRRSV SCS strain separated from Sichuan province and PRRSV of other different areas downloaded from NCBI was analyzed by bioinformatics methods comparatively,and genome mutation rules were also analyzed with the usage of anticodon.The results showed that PRRSV SCS strains genome sequence was obtained,whose nucleotide homology is among 49.1%-98.5% compared with the 11 PRRSV downloaded from NCBI. From the genetic evolution tree, it was showed that 12 PRRSV are divided into two group, AY366525, DQ864705. DQ489311 are a group, others are anothor.The nucleotide homology of PRRSV SCS strain genome sequence,EF641008 and GQ499196 is highest, and EF641008 and GQ499196 both are jiangxi strain,it was explained that sichuan popular PRRSV strain and jiangxi strain has closer genetic relationship.The mutation rules has been found by using correspondence analysis method to analyze PRRSV genetic anticodon.It has also been found that the same subtypes of PRRSV genes have similar synonymous anticodon by anticodon clustering analysis.