title: Avian influenza A H5N1 virus: a continuous threat to humans.
abstract: We report the first case of severe pneumonia due to co-infection with the emerging avian influenza A (H5N1) virus subclade 2.3.2.1 and Mycoplasma pneumoniae. The patient was a returning traveller who had visited a poultry market in South China. We then review the epidemiology, virology, interspecies barrier limiting poultry-to-human transmission, clinical manifestation, laboratory diagnosis, treatment and control measures of H5N1 clades that can be transmitted to humans. The recent controversy regarding the experiments involving aerosol transmission of recombinant H5N1 virus between ferrets is discussed. We also review the relative contribution of the poor response to antiviral treatment and the virus-induced hyperinflammatory damage to the pathogenesis and the high mortality of this infection. The factors related to the host, virus or medical intervention leading to the difference in disease mortality of different countries remain unknown. Because most developing countries have difficulty in instituting effective biosecurity measures, poultry vaccination becomes an important control measure. The rapid evolution of the virus would adversely affect the efficacy of poultry vaccination unless a correctly matched vaccine was chosen, manufactured and administered in a timely manner. Vigilant surveillance must continue to allow better preparedness for another poultry or human pandemic due to new viral mutants.
authors.affiliation: State Key Laboratory for Emerging Infectious Diseases, The University of Hong Kong , Hong Kong Special Administrative Region, China ; Research Centre of Infection and Immunology, The University of Hong Kong , Hong Kong Special Administrative Region, China ; Department of Microbiology, The University of Hong Kong , Hong Kong Special Administrative Region, China.
authors.forename: Kelvin Kw
authors.initials: KK
authors.lastname: To
authors.affiliation: Department of Pathology, Tuen Mun Hospital , Hong Kong Special Administrative Region, China.
authors.forename: Kenneth Hl
authors.initials: KH
authors.lastname: Ng
authors.affiliation: Department of Pathology, Tuen Mun Hospital , Hong Kong Special Administrative Region, China.
authors.forename: Tak-Lun
authors.initials: TL
authors.lastname: Que
authors.affiliation: Department of Medicine and Geriatrics, Princess Margaret Hospital , Hong Kong Special Administrative Region, China.
authors.forename: Jacky Mc
authors.initials: JM
authors.lastname: Chan
authors.affiliation: Department of Medicine and Geriatrics, Princess Margaret Hospital , Hong Kong Special Administrative Region, China.
authors.forename: Kay-Yan
authors.initials: KY
authors.lastname: Tsang
authors.affiliation: Research Centre of Infection and Immunology, The University of Hong Kong , Hong Kong Special Administrative Region, China ; Department of Microbiology, The University of Hong Kong , Hong Kong Special Administrative Region, China.
authors.forename: Alan Kl
authors.initials: AK
authors.lastname: Tsang
authors.affiliation: State Key Laboratory for Emerging Infectious Diseases, The University of Hong Kong , Hong Kong Special Administrative Region, China ; Research Centre of Infection and Immunology, The University of Hong Kong , Hong Kong Special Administrative Region, China ; Department of Microbiology, The University of Hong Kong , Hong Kong Special Administrative Region, China.
authors.forename: Honglin
authors.initials: H
authors.lastname: Chen
authors.affiliation: State Key Laboratory for Emerging Infectious Diseases, The University of Hong Kong , Hong Kong Special Administrative Region, China ; Research Centre of Infection and Immunology, The University of Hong Kong , Hong Kong Special Administrative Region, China ; Department of Microbiology, The University of Hong Kong , Hong Kong Special Administrative Region, China.
authors.forename: Kwok-Yung
authors.initials: KY
authors.lastname: Yuen
keywords: H5N1; avian; influenza virus; mycoplasma