RESUMO
The antigenicity of the influenza A virus hemagglutinin is responsible for vaccine efficacy in protecting pigs against swine influenza virus (SIV) infection. However, the antigenicity of SIV strains currently circulating in Japan and Vietnam has not been well characterized. We examined the antigenicity of classical H1 SIVs, pandemic A(H1N1)2009 (A(H1N1)pdm09) viruses, and seasonal human-lineage SIVs isolated in Japan and Vietnam. A hemagglutination inhibition (HI) assay was used to determine antigenic differences that differentiate the recent Japanese H1N2 and H3N2 SIVs from the H1N1 and H3N2 domestic vaccine strains. Minor antigenic variation between pig A(H1N1)pdm09 viruses was evident by HI assay using 13 mAbs raised against homologous virus. A Vietnamese H1N2 SIV, whose H1 gene originated from a human strain in the mid-2000s, reacted poorly with post-infection ferret serum against human vaccine strains from 2000-2010. These results provide useful information for selection of optimal strains for SIV vaccine production.
Assuntos
Variação Antigênica , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H1N2/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Infecções por Orthomyxoviridae/veterinária , Doenças dos Suínos/virologia , Animais , Anticorpos Monoclonais , Variação Antigênica/genética , Antígenos Virais/genética , Embrião de Galinha , Galinhas , Cães , Furões , Variação Genética , Cobaias , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N2/genética , Vírus da Influenza A Subtipo H3N2/genética , Japão/epidemiologia , Células Madin Darby de Rim Canino , Camundongos , Infecções por Orthomyxoviridae/epidemiologia , Infecções por Orthomyxoviridae/virologia , Filogenia , Ovinos , Suínos , Doenças dos Suínos/epidemiologia , Vietnã/epidemiologiaAssuntos
Surtos de Doenças , Infecções por Enterovirus/epidemiologia , Enterovirus/classificação , Enterovirus/isolamento & purificação , Doença de Mão, Pé e Boca/epidemiologia , Herpangina/epidemiologia , Animais , Linhagem Celular , Chlorocebus aethiops , Infecções por Enterovirus/virologia , Doença de Mão, Pé e Boca/virologia , Herpangina/virologia , Humanos , Japão/epidemiologia , Prevalência , Células VeroRESUMO
BACKGROUND: Sapovirus (SaV) is a pathogen of acute gastroenteritis, and contains a positive-sense single-stranded 7.5 kb RNA genome. Characterization of SaV has been mainly performed with short nucleotide sequences, and the viral load has not been widely determined. OBJECTIVES: To characterize SaV strains from two outbreaks in Nagano Prefecture, Japan, using long nucleotide sequences and to measure the viral load in feces. STUDY DESIGN: Approximately 2.3 kb of the 3' terminus of the genome corresponding to the entire capsid gene, ORF2 gene, and 3' untranslated region were amplified with semi-nested RT-PCR followed by sequencing analysis. The copy numbers of the SaV genome were determined with real-time RT-PCR. RESULTS: In Outbreak 1, SaV strains belonging to genogroup I (GI) were detected from seven symptomatic nursery children, in which six SaV isolates had identical nucleotide sequences while one had a single synonymous nucleotide substitution. In Outbreak 2, two similar GIV SaV sequences were detected, in which three nucleotide differences accompanying two non-synonymous substitutions were observed between symptomatic high school students and asymptomatic food handlers at a hotel. The cDNA copies were 1.36 x 10(7) to 1.05 x 10(11) (n=7), and 5.05 x 10(6) to 1.27 x 10(10) (n=6) per gram of stool specimens in the two outbreaks. CONCLUSIONS: The nucleotide sequence covering the 3' terminal 2.3 kb of the genome is useful for better characterization of the SaV strains. In addition, we found for the first time adults who secreted SaV with high viral loads without gastroenteritis symptoms.