Since early 2011, diarrhea was rather common among pig herds in China and the causative agent was proven to be virulent porcine epidemic diarrhea virus (PEDV). From the small intestine of a piglet showing mild diarrhea, we isolated an attenuated cell-adapted PEDV strain in a Vero cell line. The virus was designated as PEDV AH-M. The virus was recognized in infected cells by a monoclonal antibody against PEDV spike protein. After 10 passages in Vero cells, the virus grew stably to 10^6.5 TCID₅₀/ml. Typical coronavirus particles were observed by electron microscopy. The complete genome sequence of PEDV AH strain was shown to be 27, 953 nucleotides in length. On the whole genome level, this virus strain shared highly nucleotide sequence identities with attenuated Korean DR13 (99%) and China SD-M strain (99%). These data implied that a cell-adapted attenuated PEDV was isolated. We infer that AH-M could be developed as a vaccine strain while immunogenicity and pathogenicity of this strain needs further confirmation.

Key words: Complete genome sequence, Phylogenetic analyses, Porcine epidemic diarrhea virus, Vaccine