Sequencing of a porcine enterovirus strain prevalent in swine groups in China and recombination analysis

摘要

The porcine enteroviruses (PEV) belong to the family Picornaviridae, a family including at present 12 genera Enterovirus, Cardiovirus, Aphthovirus, Hepatovirus, Parechovirus, Erbovirus, Kobuvirus, Teschovirus, Sapelovirus, Senecavirus, Tremovirus and Avihepatovirus (Knowles et al., 2011). PEVs are the causative agents of neurological disorders, fertility disorders, and dermal lesions of swine (Krumbholz et al., 2002). Based on the cytopathic effect (CPE), replication properties in different host cell lines, and serological assays, the PEVs were divided into three groups: CPE group I comprises serotypes 1–7 and 11–13, CPE group II serotype 8 and CPE group III serotypes 9 and 10 (Kaku et al., 2001). Based on genomic analysis, CPE group I was categorized into a novel genus Teschovirus (species Porcine teschovirus, PTV) and ater divided in at least11distinct serotypes (PTV1–11) (Kaku et al., 2001); CPE group II was renamed as Porcine sapelovirus and reclassified into a new picornavirus genus Sapelovirus (Krumbholz et al., 2002); the members of CPE group III belong to the Enterovirus genus, based on the same genomic organization as for example human enteroviruses and rhinoviruses. Therefore, the term “porcine enteroviruses (PEVs)” was used for the identification of the members in CPE group III. (Krumbholz et al., 2002). During our studies to detect human enterovirus in water specimens using reverse transcription-PCR (RT-PCR) as previously described (Nix et al., 2006), we obtained some unexpected sequences which showed sequence homology with PEVs in CPE group III genome when we performed BLAST search in GenBank. In order to investigate whether this virus is prevalent in swine and human populations, we tested this virus in 447 swine and 220 human fecal specimens which were collected from Fuyang City, Huaibei City, and Suzhou City in central, and Fengxian District and Nanhui District in Shanghai City of eastern China from April 2009 to April 2010, using RT-PCR method. The primers used here were described previously (Zell et al., 2000), which were designed to amplify a 313 nucleotide (nt) segment from the 5′-UTR, a highly conserved region of the genome, and were capable of detecting PEV-9 and PEV-10. Results indicated that 8.3% (37/447, 95% CI 5.6–10.0) of the swine but none of the human showed positive for this virus, and the 37 nucleotide sequence fragments showed more than 98% identities (data not shown).