关键词: 猪流行性腹泻病毒, N基因, 克隆, 序列分析

Abstract: In order to understand the genetic variation of porcine epidemic diarrhea virus（PEDV） in Anhui Province, the fecal samples from pigs with suspected epidemic diarrhea in Anhui province were collected from 2013 to 2017 and were screened for the presence of PEDV antigen by using colloidal gold strip; the PEDV antigen positive samples were subjected to amplification of N gene of PEDV with RT-PCR assay; the obtained sequences were subsequently bioinformatically analyzed. The results showed that the prevalence of porcine epidemic diarrhea was identified in 6 pig farms by colloidal gold strip. RT-PCR amplification and sequencing of the clinical samples or virus passages from the 6 pig farms were carried out, and the N gene sequences of 6 epidemic strains of PEDV were obtained. All of the sequences had a length of 1 326 bp and were designated as N12, N22, N32, N42, N52 and N62, respectively. Nucleotide homology analysis showed that the sequence homology of the N genes among the 6 PEDV isolates ranged from 94.8% to 99.8%. Among them, 5 PEDV isolates （N12, N22, N32, N52 and N62） had low （94.1%~96.3%) homology and non-close genetic relationship with the PEDV vaccine strains, classical strains and Chinese isolates （LZC and CHS） before 2011, whereas had high （96.9%~99.2%） sequence homology and close genetic relationship with the domestic and foreign PEDV strains isolated after 2011. The opposite results were observed in N42. It was indicated that the new variant strains of PEDV were prevalent in pig farms in Anhui province in recent years.

Key words: porcine epidemic diarrhea virus, N gene, cloning, sequence analysis