Recombinant porcine norovirus identified from piglet with diarrhea

Result showed that 2 of the 12 evaluated fecal samples were positive for PoNoVs, one of which was positive for PoNoV alone, and the other was coinfected with porcine circovirus and PoNoV. Phylogenetic and recombination analysis showed that the PoNoV positive alone strain was a recombinant new genotype strain. Experimental infection of miniature pigs with fecal suspensions confirmed that this strain can cause gastroenteritis in piglets.This is the first report that recombinant new genotype PoNoV exised in pig herd of China, which cause diarrhea in pigs in nature condition. This find raised questions about the putative epidemiologic role of PoNoV.Noroviruses (NoVs) are members of the family Caliciviridae and are emerging enteric pathogens of humans and animals [1,2]. They are small, non-enveloped viruses of 27–38？nm in diameter and possess a single-stranded, positive-sense genomic RNA. NoVs genome is 7.3-7.7？kb in length and contains 3 open reading frames (ORFs) [3]. ORF1 encodes a polyprotein that is autocatalytically cleaved to produce several proteins, including RNA-dependent RNA-polymerase (RdRp) and other non-structural proteins [4]. ORF2 encodes the major capsid protein, and ORF3 encodes for a minor structural protein [5]. NoVs have been isolated from humans and several species of animals, including swine, canine, bovine, murine and lion [6-8]. Based on sequence analyses comprising conserved regions within the RdRp and the capsid genes, NoVs are divided into 5 genogroups (GI-GV) and further subdivided into 27 genotypes [9]. Human NoVs are located in GI, GII and GIV. GII contains 19 genotypes, and porcine strains are found in GII-11, -18 and -19 [10]. Some porcine NoVs are genetically related to human strains and are classified into GII, which contains most epidemic strains of NoVs in human. Some potential NoVs recombinant strains have been identified [10,11], which raises public health concerns regarding their potential for zoonotic transmission. To date, PoNoV