Isolation and identification of GD-A strain of porcine epidemic diarrhea virus and phylogenetic tree analyses based on S gene

Objective The fecal samples were collected from a pig farm with similar clinical symptoms of porcine epidemic diarrhea in Guangdong Province.In order to isolate a virus strain, the samples with positive RT-PCR for porcine epidemic diarrhea virus (PEDV) were inoculated in Vero cell lines.

Method The isolated virus strain was serially passaged until it was proliferated stably in Vero cells. During the process, observation of the typical cytopathic effect (CPE) at different time points, indirect fluorescent antibody (IFA) assay detected for M protein of virus, and RT-PCR method applied for specif ic gene detection of PEDV were used to isolate and identify the PEDV proliferated in Vero cells.

Result and conclusion The typical CPE was observed at the 5th bind passage, and the isolated virus strains pro liferated stably in Vero cells at the 20th passage.According to the results of RT-PCR, CPE and IFA, the isolated virus strain is determined to be PEDV, which is named GD-A strain.