Epide Miogical Investigation Of Swine FMDV In Parts Of Guangdong In 2015-2016 Year And FMDV And FMDV VP1 And 3A Gene Analysis

To analyze the genetic variation and the a ntibody level of FMDV in Guangdong from 2015 to 2016,the PRRSV antibody and antigen in serum and pathological samples were collected for detected.The results showed that the FMDV antibody positive samples was 2344 from 2763 serum samples in 2015,the pos itive rate was 84.84%,with 95% confidence interval being 78.43%-86.78%.In 2016 year,the positive samples was 2932 from 3298 serum samples,the positive rate was 88.90%,with 95% confidence interval being 86.83%-94.54%.Compared with 2015,the positive rate of antibody decreased while the positive rate of antigen increased in 2016.The experiment of FMDV VP1 and 3A gene sequence analysis was conducted,and the results showed that the 11 strains of O type FMDV strains belonged to the social spectrum type strains.7 strains of A type FMDV were Asia type strains.Compared with pandemic strains,GD-MM-3 strain and O/BY/CHA/2010 strain had the highest nucleotide homology from the 11 strains of O type FMDV strains VP1 gene,which was 95.3%;GD-1,GD-MM-1 and GD-MM-3 had the highest homology with O/MYA/1/98,which was 90.8%.Compared with pandemic strain,A/GDMM/2013 and GD-CH-3 have the highest nucleotide homology on VP1 gene,which was 99.8%.The nucleotide homology between A/GDMM/2013 and GD-CH-3 was the lowest,being 96.4%.A/Hu BWH/2009 and GD-CH-3 had the highest nucleotide homology,being 91.4%;A/Hu BWH/2009 and GD-CH-3 had the lowest nucleotide homology,being 88.4%.Compared with pandemic strain,there are 9 strains belonging to the social spectrum strain among the 11 O type FMDV 3A gene,2 strains belonging to strain pan-asian spectrum strain.7 A type FMDV 3A genes lacked some amino acids.Through the analysis of VP1 gene from simple sequences,the results showed that the five base SSR of GD-MM-2 strain had the highest relative abundance;The four bases SSR of GD-MM-1,GD-MM-2,and GD-MM-5 had the highest relative abundance;The three bases SSR of GD-ZS-1 strains had the highest relative abundance.By comparing the relative density of VP1 gene,as a result,one base SSR of GD-ZS-1 strain had the highest relative density;The two bases SSR of GD-2 had the highest relative density;The three bases SSR of GD-ZS-1 strain had the highest relative density;The four bases SSR of GD-MM-1 strain,GD-MM-2 strain and GD-MM-5 strain had the highest relative density;The five bases SSR of GD-MM-2 strain had the highest relative density.By the prediction function for O type FMDV VP1 protein structure,the highest possible section existing B cell antigen sites are 23~30,100~104,179~183,179~183.The results provided data support for the understanding of China's FMDV epidemic.Based on the above results,the pig farm achieved a good effect by using high-quality foot-and-mouth vaccine for immunization,combined with biosecurity and other measures to control foot and mouth disease.