First isolation and genetic characteristics of porcine sapeloviruses in Hunan, China

Abstract

Outbreaks of diarrhea in piglets cause serious economic consequences in China. Diarrhetic fecal samples from 20 Hunan farm piglets were tested and found to be positive for porcine epidemic diarrhea virus (PEDV) by RT-PCR, although incubation with porcine kidney (PK-15) cells failed to produce infectious PEDV. Four porcine sapelovirus (PSV) strains (designated as PSV-HuNs) were isolated from four of the samples. Genomic sequence analysis revealed open reading frames encoding polyproteins of 2,331 (HuN1, 2 and 3) and 2,332 (HuN4) amino acids. Homology comparisons of the VP1 gene of the four Hunan strains with previously reported PSV strains revealed nucleotide sequence identities ranging from 74.2 to 98.6%, and deduced amino acid sequence identities from 79.5 to 98%. Phylogenetic analyses based on full-length and partial VP1 gene sequences showed that 3 of the PSV-HuN strains (HuN2, 3 and 4) clustered within a clade distinct from HuN1 as well as from all PSVs previously isolated in China, thereby showing that genetic diversity exists within Chinese PSVs. In addition, recombination analysis among PSVs indicates that a recombinant (HuN2 strain) exist in China.

High prevalence, genetic diversity and a potentially novel genotype of Sapelovirus A (Picornaviridae) in enteric and respiratory samples in Hungarian swine farms

“…Serotyping of historic porcine 'enteroviruses' including sapelovirus strains has traditionally been largely based on neutralization or indirect immunofluorescence assays using multiple sets of serotype-specific monoclonal antibodies applied on cultured viruses [35,36]. Although most PSVs are able to replicate in cell lines of swine-origin including PK-15 [5][6][7] all the cultivation attempts of PSV strain SZ1M-F/PSV/HUN/2013 in PK-15 cell cultures failed despite the relatively high initial viral copy number (2.90E+06 copies/ml) of the virus in the sample used for inoculation. It is currently not known whether SZ1M-F/ PSV/HUN/2013 is unable to grow in PK-15 cell line or the sample did not contain replication competent PSV viruses, but the classical serotyping of SZ1M-F/PSV/HUN/2013 using antibody-based serological assay could therefore not be conducted.…”

“…The first strains of PSVs (formerly called PEV-8) as members of the historic group of porcine 'enteroviruses' were isolated more than 50 years ago from faecal samples of swine using cell cultures with various swine-derived cell lines [2][3][4]. Since then porcine kidney cell lines such as LLC-PK or PK-15 are widely used for isolation and typing of PSVs [5][6][7].…”

“…Porcine sapeloviruses have been associated with a wide variety of diseases including diarrhea, pneumonia and reproductive disorders like SMEDI (stillbirth, mummification, embryonic death and infertility) syndrome [4,8,9] of pigs, although due to the relatively high prevalence of PSVs detected in asymptomatic animals the exact role of natural PSV infections in such diseases are not yet definitely established [7,10]. Nevertheless certain neurotropic PSV strains are increasingly associated with various CNS-related symptoms of swine including paralysis and paraplegia of various severity [11,12].…”

“…Although PSVs are known to be a genetically highly diverse group of viruses, with recombination potential, only a single genotype of PSV has been identified based largely on VP1 sequence analyses [10,16,20]. Beside the recently published large-scale epidemiological studies on PSV conducted mostly in Far East countries such as China and Japan [7,10,20] little information is available about the prevalence and genetic diversity of PSVs circulating in Europe particularly in Hungary. Mostly single PSV strains or partial PSV sequences have been described from European countries including Spain, France and Italy [21][22][23].…”

Genetic and Biological Diversity of Porcine Sapeloviruses Prevailing in Zambia

“…Since the first detection of PSV in the UK in 1958 [5], it has been identified in many countries, including the USA, Brazil, Australia, Japan, China, South Korea, India, Germany, France, Italy, the Czech Republic, and the UK [4,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. In Kenya and Uganda, a genomic fragment of PSV was detected from pig feces by metagenomic analysis [24], but the prevalence and genetic diversity of PSVs in Africa are totally unknown.…”