Swine influenza A virus（swine IAV） circulates worldwide in pigs and poses a serious public health threat, as evidenced by the 2009 H1N1 influenza pandemic. Among multiple subtypes/lineages of swine influenza A virus...Swine influenza A virus（swine IAV） circulates worldwide in pigs and poses a serious public health threat, as evidenced by the 2009 H1N1 influenza pandemic. Among multiple subtypes/lineages of swine influenza A viruses, European avian-like（EA） H1N1 swine IAV has been dominant since 2005 in China and caused infections in humans in 2010. Highly sensitive and specific methods of detection are required to differentiate EA H1N1 swine IAVs from viruses belonging to other lineages and subtypes. In this study, a nested reverse transcription（RT）-PCR assay was developed to detect EA H1 swine IAVs. Two primer sets（outer and inner） were designed specifically to target the viral hemagglutinin genes. Specific PCR products were obtained from all tested EA H1N1 swine IAV isolates, but not from other lineages of H1 swine IAVs, other subtypes of swine IAVs, or other infectious swine viruses. The sensitivity of the nested RT-PCR was improved to 1 plaque forming unit（PFU） m L^（-1） which was over 10~4 PFU m L^（-1） for a previously established multiplex RT-PCR method. The nested RT-PCR results obtained from screening 365 clinical samples were consistent with those obtained using conventional virus isolation methods combined with sequencing. Thus, the nested RT-PCR assay reported herein is more sensitive and suitable for the diagnosis of clinical infections and surveillance of EA H1 swine IAVs in pigs and humans.展开更多
Eurasian avian-like H1 N1(EA H1 N1)swine influenza virus(SIV)outside European countries was first detected in Hong Kong Special Administrative Region(Hong Kong,SAR)of China in 2001.Afterwards,EA H1 N1 SIVs have become...Eurasian avian-like H1 N1(EA H1 N1)swine influenza virus(SIV)outside European countries was first detected in Hong Kong Special Administrative Region(Hong Kong,SAR)of China in 2001.Afterwards,EA H1 N1 SIVs have become predominant in pig population in this country.However,the epidemiology and genotypic diversity of EA H1 N1 SIVs in China are still unknown.Here,we collected the EA H1 N1 SIVs sequences from China between 2001 and 2018 and analyzed the epidemic and phylogenic features,and key molecular markers of these EA H1 N1 SIVs.Our results showed that EA H1 N1 SIVs distributed in nineteen provinces/municipalities of China.After a long-time evolution and transmission,EA H1 N1 SIVs were continuously reassorted with other co-circulated influenza viruses,including 2009 pandemic H1 N1(A(H1 N1)pdm09),and triple reassortment H1 N2(TR H1 N2)influenza viruses,generated 11 genotypes.Genotype 3 and 5,both of which were the reassortments among EA H1 N1,A(H1 N1)pdm09 and TR H1 N2 viruses with different origins of M genes,have become predominant in pig population.Furthermore,key molecular signatures were identified in EA H1 N1 SIVs.Our study has drawn a genotypic diversity image of EA H1 N1 viruses,and could help to evaluate the potential risk of EA H1 N1 for pandemic preparedness and response.展开更多
基金supported by the National High-Tech R&D Program of China (2012AA101303)
文摘Swine influenza A virus（swine IAV） circulates worldwide in pigs and poses a serious public health threat, as evidenced by the 2009 H1N1 influenza pandemic. Among multiple subtypes/lineages of swine influenza A viruses, European avian-like（EA） H1N1 swine IAV has been dominant since 2005 in China and caused infections in humans in 2010. Highly sensitive and specific methods of detection are required to differentiate EA H1N1 swine IAVs from viruses belonging to other lineages and subtypes. In this study, a nested reverse transcription（RT）-PCR assay was developed to detect EA H1 swine IAVs. Two primer sets（outer and inner） were designed specifically to target the viral hemagglutinin genes. Specific PCR products were obtained from all tested EA H1N1 swine IAV isolates, but not from other lineages of H1 swine IAVs, other subtypes of swine IAVs, or other infectious swine viruses. The sensitivity of the nested RT-PCR was improved to 1 plaque forming unit（PFU） m L^（-1） which was over 10~4 PFU m L^（-1） for a previously established multiplex RT-PCR method. The nested RT-PCR results obtained from screening 365 clinical samples were consistent with those obtained using conventional virus isolation methods combined with sequencing. Thus, the nested RT-PCR assay reported herein is more sensitive and suitable for the diagnosis of clinical infections and surveillance of EA H1 swine IAVs in pigs and humans.
基金supported by the National Nature Science Foundation of China(81961128002,81971941,and 31761133003)
文摘Eurasian avian-like H1 N1(EA H1 N1)swine influenza virus(SIV)outside European countries was first detected in Hong Kong Special Administrative Region(Hong Kong,SAR)of China in 2001.Afterwards,EA H1 N1 SIVs have become predominant in pig population in this country.However,the epidemiology and genotypic diversity of EA H1 N1 SIVs in China are still unknown.Here,we collected the EA H1 N1 SIVs sequences from China between 2001 and 2018 and analyzed the epidemic and phylogenic features,and key molecular markers of these EA H1 N1 SIVs.Our results showed that EA H1 N1 SIVs distributed in nineteen provinces/municipalities of China.After a long-time evolution and transmission,EA H1 N1 SIVs were continuously reassorted with other co-circulated influenza viruses,including 2009 pandemic H1 N1(A(H1 N1)pdm09),and triple reassortment H1 N2(TR H1 N2)influenza viruses,generated 11 genotypes.Genotype 3 and 5,both of which were the reassortments among EA H1 N1,A(H1 N1)pdm09 and TR H1 N2 viruses with different origins of M genes,have become predominant in pig population.Furthermore,key molecular signatures were identified in EA H1 N1 SIVs.Our study has drawn a genotypic diversity image of EA H1 N1 viruses,and could help to evaluate the potential risk of EA H1 N1 for pandemic preparedness and response.
