Investigation and analysis on molecular epidemiology of porcine epidemic diarrhea virus in south China

In order to know the epidemic, variation and evolution of porcine epidemic diarrhea virus (PEDV) in south China, 2159 samples were collected from different herds in south China. In this study, partial spike (S), ORF3, and membrane (M) genes amplified from these samples were sequenced and analyzed. While, the morbidity and mortality rate of herds mentioned above was counted. The results showed that all of the herds were positive for PEDV, the average positive rate of PEDV was 53.0%. However, the mean positive rate of PEDV in suckling piglets, nursing piglets, finishing pigs and sows were 67.6%，42.8%，12.8% and 47.2%, respectively. The phylogenetic trees that were constructed by MEGA based on partial S, M and ORF3 genes, showed that all the PEDV analyzed fell into two groups, which were consisted by present fields strains and reference strains. These results indicated that PEDV was prevalent in the field herds in south China and variant in PEDV genes.