No abstract

No abstract

HighlightsPhylogeographic analyses of H5N8, including 49 new sequences from South Korea.H5N8 movement was mostly among areas dense in wild and domestic ducks.New viral introductions to South Korea occurred at time of wild bird migration.H5N8 epidemiology is shaped by wild waterfowl migration and domestic duck density.H5N8 may have entered Europe at least twice, and Asia at least three times.

Inoculated wild ducks showed few symptoms but transmitted H5N8 viruses to other ducks.

Current influenza vaccines do not provide good protection against antigenically different influenza A viruses. As an approach to overcome strain specificity of protection, this study demonstrates significantly improved long-term cross protection by supplementing split vaccines with a conserved molecular target, a repeat of the influenza M2 ectodomain (M2e) expressed on virus-like particles (M2e5x VLPs) in a membrane-anchored form. Intramuscular immunization with H1N1 split vaccine (A/California/07/2009) supplemented with M2e5x VLPs induced M2e-specific humoral and cellular immune responses, and shaped the host responses to the vaccine in the direction of T-helper type 1 responses inducing dominant IgG2a isotype antibodies as well as interferon-γ (IFN-γ) producing cells in systemic and mucosal sites. Upon lethal challenge, M2e5x VLP-supplemented vaccination lowered lung viral loads and induced long-term cross protection against H3N2 or H5N1 subtype influenza viruses over 12 months. M2e antibodies, CD4 T cells, and CD8 T cells were found to contribute to improving heterosubtypic cross protection. In addition, improved cross protection by supplemented vaccination with M2e5x VLPs was mediated via Fc receptors. The results support evidence that supplementation with M2e5x VLPs is a promising approach for overcoming the limitation of strain-specific protection by current influenza vaccination.

The objective of this study was to assess trends in the prevalence and distribution of gram-negative bacteria isolated from bovine mastitis and their antimicrobial susceptibilities during a 6-yr period between 2003 and 2008 in Korea. Escherichia coli, Pseudomonas fluorescens, Klebsiella pneumoniae, Enterobacter cloacae, Acinetobacter lwoffi/junii, Pseudomonas aeruginosa, and Serratia marcescens were the most commonly observed pathogens during this period. Generally, gram-negative bacteria showed low susceptibilities to most of the antimicrobials tested in this study, except amikacin and gentamicin. Although these 2 aminoglycosides were broadly active against gram-negative bacteria, less than half of those bacteria showed susceptibilities to streptomycin. The beta-lactams, except piperacillin, had the lowest activity among antimicrobials tested in this study. Susceptibilities to chloramphenicol and trimethoprim were fairy high in all genera of gram-negative bacteria, except Acinetobacter spp. and Pseudomonas spp., whereas relatively high resistance to tetracycline was observed uniformly among gram-negative bacteria. There was no significant change in the prevalence of bacterial and the proportion of antimicrobial resistance among gram-negative bacteria isolates during a 6-yr period.

Highly pathogenic avian influenza (H5N1) among wild birds emerged simultaneously with outbreaks in domestic poultry in South Korea during November 2010–May 2011. Phylogenetic analysis showed that these viruses belonged to clade 2.3.2, as did viruses found in Mongolia, the People’s Republic of China, and Russia in 2009 and 2010.

Avian influenza virus (AIV) circulates among free-ranging, wild birds. We optimized and validated a DNA barcoding technique for AIV isolation and host-species identification using fecal samples from wild birds. DNA barcoding was optimized using tissue and fecal samples from known bird species, and the method was shown to distinguish 26 bird species. Subsequently, fecal samples (n=743) collected from wild waterfowl habitats confirmed the findings from the laboratory tests. All identified AIV-positive hosts (n=35) were members of the order Anseriformes. We successfully applied the DNA barcoding technique to AIV surveillance and examined AIV epidemiology and host ecology in these wild waterfowl populations. This methodology may be useful in the design of AIV surveillance strategies.