Epidemiology of human infections with avian influenza A(H7N9) virus in China.

BACKGROUND The first identified cases of avian influenza A(H7N9) virus infection in humans occurred in China during February and March 2013. We analyzed data obtained from field investigations to describe the epidemiologic characteristics of H7N9 cases in China identified as of December 1, 2013. METHODS Field investigations were conducted for each confirmed case of H7N9 virus infection. A patient was considered to have a confirmed case if the presence of the H7N9 virus was verified by means of real-time reverse-transcriptase-polymerase-chain-reaction assay (RT-PCR), viral isolation, or serologic testing. Information on demographic characteristics, exposure history, and illness timelines was obtained from patients with confirmed cases. Close contacts were monitored for 7 days for symptoms of illness. Throat swabs were obtained from contacts in whom symptoms developed and were tested for the presence of the H7N9 virus by means of real-time RT-PCR. RESULTS Among 139 persons with confirmed H7N9 virus infection, the median age was 61 years (range, 2 to 91), 71% were male, and 73% were urban residents. Confirmed cases occurred in 12 areas of China. Nine persons were poultry workers, and of 131 persons with available data, 82% had a history of exposure to live animals, including chickens (82%). A total of 137 persons (99%) were hospitalized, 125 (90%) had pneumonia or respiratory failure, and 65 of 103 with available data (63%) were admitted to an intensive care unit. A total of 47 persons (34%) died in the hospital after a median duration of illness of 21 days, 88 were discharged from the hospital, and 2 remain hospitalized in critical condition; 2 patients were not admitted to a hospital. In four family clusters, human-to-human transmission of H7N9 virus could not be ruled out. Excluding secondary cases in clusters, 2675 close contacts of case patients completed the monitoring period; respiratory symptoms developed in 28 of them (1%); all tested negative for H7N9 virus. CONCLUSIONS Most persons with confirmed H7N9 virus infection had severe lower respiratory tract illness, were epidemiologically unrelated, and had a history of recent exposure to poultry. However, limited, nonsustained human-to-human H7N9 virus transmission could not be ruled out in four families.

[1]  C. Bridges,et al.  Case-control study of risk factors for avian influenza A (H5N1) disease, Hong Kong, 1997. , 1999, The Journal of infectious diseases.

[2]  A. Osterhaus,et al.  For Personal Use. Only Reproduce with Permission from the Lancet , 2022 .

[3]  Martin Hirst,et al.  Human Illness from Avian Influenza H7N3, British Columbia , 2004, Emerging infectious diseases.

[4]  Marion Koopmans,et al.  Avian influenza A virus (H7N7) associated with human conjunctivitis and a fatal case of acute respiratory distress syndrome. , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[5]  Prasert Auewarakul,et al.  Probable person-to-person transmission of avian influenza A (H5N1). , 2005, The New England journal of medicine.

[6]  Weizhong Yang,et al.  The first confirmed human case of avian influenza A (H5N1) in Mainland China , 2006, The Lancet.

[7]  Yi Guan,et al.  Three Indonesian clusters of H5N1 virus infection in 2005. , 2006, The New England journal of medicine.

[8]  Collective Editorial team.  Avian influenza A/(H7N2) outbreak in the United Kingdom. , 2007, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[9]  Weizhong Yang,et al.  Human Influenza A (H5N1) Cases, Urban Areas of People’s Republic of China, 2005–2006 , 2007, Emerging infectious diseases.

[10]  A. Kumar,et al.  Three Indonesian Clusters of H5N1 Virus Infection in 2005 , 2008 .

[11]  Timothy M. Uyeki,et al.  Incubation Period for Human Cases of Avian Influenza A (H5N1) Infection, China , 2008, Emerging infectious diseases.

[12]  Zhongjie Li,et al.  Clinical Characteristics of 26 Human Cases of Highly Pathogenic Avian Influenza A (H5N1) Virus Infection in China , 2008, PLoS ONE.

[13]  Yu Wang,et al.  Probable limited person-to-person transmission of highly pathogenic avian influenza A (H5N1) virus in China , 2008, The Lancet.

[14]  N. Cox,et al.  Prevention and control of seasonal influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP), 2009. , 2009 .

[15]  C. Bridges,et al.  Past, Present, and Possible Future Human Infection with Influenza Virus A Subtype H7 , 2009, Emerging infectious diseases.

[16]  Weizhong Yang,et al.  Risk factors for human illness with avian influenza A (H5N1) virus infection in China. , 2009, The Journal of infectious diseases.

[17]  N. Dreyer,et al.  Effectiveness of antiviral treatment in human influenza A(H5N1) infections: analysis of a Global Patient Registry. , 2010, The Journal of infectious diseases.

[18]  J. Kaldor,et al.  Prevention and control of influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP), 2010. , 2010, MMWR. Recommendations and reports : Morbidity and mortality weekly report. Recommendations and reports.

[19]  Weizhong Yang,et al.  Risk factors for severe illness with 2009 pandemic influenza A (H1N1) virus infection in China. , 2011, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[20]  Robert Schechter,et al.  Treatment with neuraminidase inhibitors for critically ill patients with influenza A (H1N1)pdm09. , 2012, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[21]  Christl A. Donnelly,et al.  Transmission Dynamics, Border Entry Screening, and School Holidays during the 2009 Influenza A (H1N1) Pandemic, China , 2012, Emerging infectious diseases.

[22]  S. Lindstrom,et al.  Low Pathogenic Avian Influenza A (H7N2) Virus Infection in Immunocompromised Adult, New York, USA, 2003 , 2012, Emerging infectious diseases.

[23]  P. Zhang,et al.  Mild Illness in Avian Influenza A(H7N9) Virus–Infected Poultry Worker, Huzhou, China, April 2013 , 2013, Emerging infectious diseases.

[24]  Y. Shu,et al.  Serologic study for influenza A (H7N9) among high-risk groups in China. , 2013, The New England journal of medicine.

[25]  G. Gao,et al.  Live-animal markets and influenza A (H7N9) virus infection. , 2013, The New England journal of medicine.

[26]  Noriko Kishida,et al.  Characterization of H7N9 influenza A viruses isolated from humans , 2013, Nature.

[27]  D. Burke,et al.  Limited airborne transmission of influenza A/H7N9 virus between ferrets , 2013, Nature.

[28]  B. Shao,et al.  Epidemiological link between exposure to poultry and all influenza A(H7N9) confirmed cases in Huzhou city, China, March to May 2013. , 2013, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[29]  G. Shi,et al.  Case-control study of risk factors for human infection with influenza A(H7N9) virus in Jiangsu Province, China, 2013. , 2013, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[30]  W. Xu,et al.  Serological Investigation of Subclinical Influenza A(H7H9) Infection Among Healthcare and Non–Healthcare Workers in Zhejiang Province, China , 2013, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[31]  Bin Cao,et al.  Human infection with avian influenza A H7N9 virus: an assessment of clinical severity , 2013, The Lancet.

[32]  Guohua Deng,et al.  H7N9 Influenza Viruses Are Transmissible in Ferrets by Respiratory Droplet , 2013, Science.

[33]  Jie Dong,et al.  Human Infection with a Novel Avian-Origin Influenza A (H7N9) Virus. , 2018 .

[34]  M. Peiris,et al.  Association between adverse clinical outcome in human disease caused by novel influenza A H7N9 virus and sustained viral shedding and emergence of antiviral resistance , 2013, The Lancet.

[35]  T. Tumpey,et al.  Pathogenesis and transmission of avian influenza A (H7N9) virus in ferrets and mice , 2013, Nature.

[36]  Qun Li,et al.  Use of National Pneumonia Surveillance to Describe Influenza A(H7N9) Virus Epidemiology, China, 2004–2013 , 2013, Emerging infectious diseases.

[37]  Hui Jiang,et al.  Comparative epidemiology of human infections with avian influenza A H7N9 and H5N1 viruses in China: a population-based study of laboratory-confirmed cases , 2013, The Lancet.

[38]  T. Kuiken,et al.  Novel avian-origin influenza A (H7N9) virus attaches to epithelium in both upper and lower respiratory tract of humans. , 2013, The American journal of pathology.

[39]  Lu Lu,et al.  healthcare and non-healthcare workers in Zhejiang Province of China , 2013 .

[40]  Jian He,et al.  Clinical findings in 111 cases of influenza A (H7N9) virus infection. , 2013, The New England journal of medicine.

[41]  Jo Leonardi-Bee,et al.  Impact of Neuraminidase Inhibitor Treatment on Outcomes of Public Health Importance During the 2009–2010 Influenza A(H1N1) Pandemic: A Systematic Review and Meta-Analysis in Hospitalized Patients , 2012, The Journal of infectious diseases.

[42]  Weizhong Yang,et al.  Biological features of novel avian influenza A (H7N9) virus , 2013, Nature.

[43]  Pi-Han Lin,et al.  The first case of H7N9 influenza in Taiwan , 2013, The Lancet.

[44]  Weizhong Yang,et al.  Detection of mild to moderate influenza A/H7N9 infection by China’s national sentinel surveillance system for influenza-like illness: case series , 2013, BMJ.

[45]  Wenjun Song,et al.  Human infections with the emerging avian influenza A H7N9 virus from wet market poultry: clinical analysis and characterisation of viral genome , 2013, The Lancet.

[46]  Dayan Wang,et al.  Monitoring Avian Influenza A(H7N9) Virus through National Influenza-like Illness Surveillance, China , 2013, Emerging infectious diseases.

[47]  Jing Luo,et al.  Relationship between domestic and wild birds in live poultry market and a novel human H7N9 virus in China. , 2014, The Journal of infectious diseases.

[48]  Benjamin J Cowling,et al.  Effect of closure of live poultry markets on poultry-to-person transmission of avian influenza A H7N9 virus: an ecological study , 2014, The Lancet.

[49]  Honglin Chen,et al.  Novel avian-origin human influenza A(H7N9) can be transmitted between ferrets via respiratory droplets. , 2014, The Journal of infectious diseases.