Conservation of T cell epitopes between seasonal inlfuenza viruses and the novel inlfuenza A H7N9 virus / 中国病毒学·英文版

A novel avian influenza A (H7N9) virus recently emerged in the Yangtze River delta and caused diseases, often severe, in over 130 people. This H7N9 virus appeared to infect humans with greater ease than previous avian inlfuenza virus subtypes such as H5N1 and H9N2. While there are other potential explanations for this large number of human infections with an avian influenza virus, we investigated whether a lack of conserved T-cell epitopes between endemic H1N1 and H3N2 inlfuenza viruses and the novel H7N9 virus contributes to this observation. Here we demonstrate that a number of T cell epitopes are conserved between endemic H1N1 and H3N2 viruses and H7N9 virus. Most of these conserved epitopes are from viral internal proteins. The extent of conservation between endemic human seasonal inlfuenza and avian inlfuenza H7N9 was comparable to that with the highly pathogenic avian inlfuenza H5N1. Thus, the ease of inter-species transmission of H7N9 viruses (compared with avian H5N1 viruses) cannot be attributed to the lack of conservation of such T cell epitopes. On the contrary, our ifndings predict signiifcant T-cell based cross-reactions in the human population to the novel H7N9 virus. Our findings also have implications for H7N9 virus vaccine design.

Evidence for avian H9N2 influenza virus infections among rural villagers in Cambodia

Southeast Asia remains a critical region for the emergence of novel and/or zoonotic influenza, underscoring the importance of extensive sampling in rural areas where early transmission is most likely to occur. In 2008, 800 adult participants from eight sites were enrolled in a prospective population-based study of avian influenza [AI] virus transmission where highly pathogenic avian influenza [HPAI] H5N1 virus had been reported in humans and poultry from 2006 to 2008. From their enrollment sera and questionnaires, we report risk factor findings for serologic evidence of previous infection with 18 AI virus strains. Serologic assays revealed no evidence of previous infection with 13 different low-pathogenic AI viruses or with HPAI avian-like A/Cambodia/R0404050/2007[H5N1]. However, 21 participants had elevated antibodies against avian-like A/Hong Kong/1073/1999[H9N2], validated with a monoclonal antibody blocking ELISA assay specific for avian H9. Although cross-reaction from antibodies against human influenza viruses cannot be completely excluded, the study data suggest that a number of participants were previously infected with the avian-like A/Hong Kong/1073/1999[H9N2] virus, likely due to as yet unidentified environmental exposures. Prospective data from this cohort will help us better understand the serology of zoonotic influenza infection in a rural cohort in SE Asia

Novel Coronaviruses and Astroviruses in Bats / 中国病毒学·英文版

Zoonotic transmissions of emerging pathogens from wildlife to human have shaped the history of mankind. These events have also highlighted our poor understanding of microorganisms circulated in wild animals. Coronaviruses and astroviruses, which can be found from a wide range of mammals, were recently detected in bats. Strikingly, these bat viruses are genetically highly diverse and these interesting findings might help to better understand the evolution and ecology of these viruses. The discoveries of these novel bats viruses not only suggested that bats are important hosts for these virus families, but also reiterated the role of bats as a reservoir of viruses that might pose a zoonotic threat to human health.