FMDV Serological Survey And FMDV VP1 Gene Analysis Parts Of Guangdong

Foot-and-mouth Disease(FMD) is composed of foot-and-mouth Disease Virus(FMDV) caused by the height of the main assault artiodactyl contact people and animals suffering from infectious diseases, the Disease continued popular all over the world for aquaculture caused enormous economic loss.In order to understand the epidemiological characters of foot-and mouth disease in Guangdong province in the last two years, we tested the FMD-ab of swine serum collected from guangdong in 2013-2014, result: the positive rate of FMD-ab in 2013 is 81.61%(2662/3262,95% CI:80.23%-82.92%); the positive rate of FMD-ab in 2014 is 91.88%(2704/2943,95% CI:90.83%-92.84%) the result reflect a increasing tendency of FMD positive rate, so, it should cause the attention of relevant departments, strengthen the foot-and-mouth disease detection, prevention and control.We did RT-PCR detection and VP1 gene sequence analysis of 17 FMD suspected strains of swine collected from guangdong province, the result indicates that all the 17 samples are O type FMD. The 17 strains have a highest homology to O/BY/CHA 2010 strain( homology rates are between 94.2%-97.2%). Genetic evolution tree of VP1 nucleotide sequences were analyzed, and the result showed that same as the O/BY/CHA/2010 strain witch is the main epidemic type in Guangdong area now, all the 17 sample are on the ES-SA branch, and all belong to the Gengma pedigree. We analysised the variability of VP1 amino acid sites, the result showed that the VP1 gene mutation hot pots are in 23 ~ 27, 45 ~ 58, 135 ~ 145, and 149 ~ 159 lucases. Through the theoretical study of FMDV Z curve, the result shows that each subtype virus has its own unique Z curve. Through analyzing strain Ka/Ks molecular evolution, the results show that the separation experiment of 17 strains have purification selection effect. Of FMDV codon use relative probability analysis, the results show that as the choice of evolutionary pressures, Gly, Arg, Ser optimal codon changes. Through correlation analysis of synonymous codon position different GC content, results show that the GC1 and GC2, GC3, GC12, Gcall and significantly correlation between ENC; GC2 and Gcall extremely significant correlation, and GC3 and GC12 significant correlation, and ENC irrelevant; GC3 and GC12, Gcall and significantly correlation between ENC; ENC and GC12 show significant correlation. Through the analysis of the correlation between ENC and GC3, the results show that SGDHZ-03-2014 strains only affected by choice; S-GDDW-2013 seedlings, S-HD-2012-Yangdong-2013 seedlings, S-Bole-2012, S-GDGZ-12-2014 is only affected by mutation. Study of FMDV VP1 help for us to predict the virus genetic evolution,Based on VP1 gene molecular evolution analysis and codon biased analysis, provide us help for our forecast on virus genetic evolution, also for the epidemiological study of FMD, the track of epidemic source, the strain poisonous type and subtype analysis, and reasonable selection of vaccine at the same time, even for the preparation of diagnostic antigen and the development of new vaccines provide theoretical guidance.