title: Viral lung infections: epidemiology, virology, clinical features, and management of avian influenza A(H7N9).
abstract: OBJECTIVE
  The avian influenza A(H7N9) virus has jumped species barrier and caused severe human infections. Here, we present the virological features relevant to clinical practice, and summarize the epidemiology, clinical findings, diagnosis, treatment, and preventive strategies of A(H7N9) infection.
  
  
  RESULTS
  As of 18 February 2014, A(H7N9) virus has caused 354 infections in mainland China, Taiwan, and Hong Kong with a case-fatality rate of 32%. Elderly men were most affected. Most patients acquired the infection from direct contact with poultry or from a contaminated environment, although person-to-person transmission has likely occurred. A(H7N9) infection has usually presented with severe pneumonia, often complicated by acute respiratory distress syndrome and multiorgan failure. Mild infections have been reported in children and young adults. Nasopharyngeal aspirate and sputum samples should be collected for diagnosis, preferably using reverse transcriptase-PCR. Early treatment with neuraminidase inhibitors improved survival, but the efficacy of antivirals was hampered by resistant mutants. The closure of live poultry markets in affected areas has significantly contributed to the decline in the incidence of human cases.
  
  
  CONCLUSIONS
  The emergence of A(H7N9) virus represents a significant health threat. High vigilance is necessary so that appropriate treatment can be instituted for the patient and preventive measures can be implemented.
authors.affiliation: State Key Laboratory for Emerging Infectious Diseases, Carol Yu Centre for Infection, Research Centre of Infection and Immunology, Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region, China.
authors.forename: Kelvin K-W
authors.initials: KK
authors.lastname: To
authors.forename: Jasper F-W
authors.initials: JF
authors.lastname: Chan
authors.forename: Kwok-Yung
authors.initials: KY
authors.lastname: Yuen
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000008:administration & dosage; D002681:China / Q000453:epidemiology; D003132:Commerce; D003140:Communicable Disease Control / Q000379:methods*; D021821:Communicable Diseases, Emerging / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission / Q000821:virology; D004196:Disease Outbreaks / Q000517:prevention & control*; D024921:Drug Resistance, Multiple, Viral; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D005523:Food Supply; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D064766:Influenza A Virus, H7N9 Subtype / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission / Q000821:virology; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission / Q000821:virology; D009439:Neuraminidase / Q000037:antagonists & inhibitors; D011200:Poultry / Q000821:virology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013624:Taiwan / Q000453:epidemiology; D053243:Zanamivir / Q000008:administration & dosage; D015047:Zoonoses
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D009439:Neuraminidase; D053243:Zanamivir