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Nosocomial transmission of avian influenza A (H7N9) virus in China: epidemiological investigation

BMJ 2015; 351 doi: https://doi.org/10.1136/bmj.h5765 (Published 19 November 2015) Cite this as: BMJ 2015;351:h5765
  1. Chun-Fu Fang, director1,
  2. Mai-Juan Ma, epidemiologist2,
  3. Bing-Dong Zhan, epidemiologist1,
  4. Shi-Ming Lai, deputy director1,
  5. Yi Hu, virologist2,
  6. Xiao-Xian Yang, molecular biologist2,
  7. Jing Li, virologist2,
  8. Guo-Ping Cao, epidemiologist1,
  9. Jing-Jing Zhou, molecular biologist2,
  10. Jian-Min Zhang, public health officer1,
  11. Shuang-Qing Wang, public health officer1,
  12. Xiao-Long Hu, public health officer1,
  13. Yin-Jun Li, public health officer2,
  14. Xiao-Xiao Wang, epidemiologist3,
  15. Wei Cheng, epidemiologist3,
  16. Hong-Wu Yao, molecular biologist2,
  17. Xin-Lou Li, molecular biologist2,
  18. Huai-Ming Yi, epidemiologist4,
  19. Wei-Dong Xu, doctor5,
  20. Jia-Fu Jiang, epidemiologist2,
  21. Gregory C Gray, professor6,
  22. Li-Qun Fang, epidemiologist2,
  23. En-Fu Chen, epidemiologist3,
  24. Wu-Chun Cao, professor2
  1. 1Quzhou Center for Disease Control and Prevention, Quzhou, China
  2. 2State Key Laboratory of Pathogen and Security, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
  3. 3Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
  4. 4Changshan County Center for Disease Control and Prevention, Changshan, China
  5. 5Kecheng District People’s Hospital, Quzhou
  6. 6Division of Infectious Diseases, Global Health Institute, & Nicholas School of the Environment, Duke University, Duke University Medical Center, Durham, NC, USA
  1. Correspondence to: W-C Cao caowc{at}bmi.ac.cn
  • Accepted 13 October 2015

Abstract

Study question Can avian influenza A (H7N9) virus be transmitted between unrelated individuals in a hospital setting?

Methods An epidemiological investigation looked at two patients who shared a hospital ward in February 2015, in Quzhou, Zhejiang Province, China. Samples from the patients, close contacts, and local environments were examined by real time reverse transcriptase (rRT) polymerase chain reaction (PCR) and viral culture. Haemagglutination inhibition and microneutralisation assays were used to detect specific antibodies to the viruses. Primary outcomes were clinical data, infection source tracing, phylogenetic tree analysis, and serological results.

Study answer and limitations A 49 year old man (index patient) became ill seven days after visiting a live poultry market. A 57 year old man (second patient), with a history of chronic obstructive pulmonary disease, developed influenza-like symptoms after sharing the same hospital ward as the index patient for five days. The second patient had not visited any poultry markets nor had any contact with poultry or birds within 15 days before the onset of illness. H7N9 virus was identified in the two patients, who both later died. Genome sequences of the virus isolated from both patients were nearly identical, and genetically similar to the virus isolated from the live poultry market. No specific antibodies were detected among 38 close contacts. Transmission between the patients remains unclear, owing to the lack of samples collected from their shared hospital ward. Although several environmental swabs were positive for H7N9 by rRT-PCR, no virus was cultured. Owing to delayed diagnosis and frequent hospital transfers, no serum samples were collected from the patients, and antibodies to H7N9 viruses could not be tested.

What this study adds Nosocomial H7N9 transmission might be possible between two unrelated individuals. Surveillance on patients with influenza-like illness in hospitals as well as chickens in live poultry markets should be enhanced to monitor transmissibility and pathogenicity of the virus.

Funding, competing interests, data sharing Funding support from the Program of International Science and Technology Cooperation of China (2013DFA30800), Basic Work on Special Program for Science and Technology Research (2013FY114600), National Natural Science Foundation of China (81402730), Special Program for Prevention and Control of Infectious Diseases in China (2013ZX10004218), US National Institutes of Health (1R01-AI108993), Zhejiang Province Major Science and Technology Program (2014C03039), and Quzhou Science and Technology Program (20111084). The authors declare no other interests and have no additional data.

Footnotes

  • We thank all the healthcare workers who helped us in this work, and all the participants for their cooperation.

  • Contributors: M-JM, GCG, L-QF, and W-CC designed the study. C-FF, M-JM, B-DZ, L-QF, GCG, E-FC, and W-CC drafted the manuscript. C-FF, B-DZ, S-ML, G-PC, J-MZ, S-QW, X-LH, E-FC, Y-JL, X-XW, WC, J-FJ, H-MY, and W-DX conducted the epidemiological investigation and collected samples. M-JM, YH, X-XY, JL, J-JZ, H-WY, and X-LL performed laboratory assays. All authors contributed to the development of the manuscript and approved the final draft. C-FF, M-JM, and B-DZ contributed equally to this study. L-QF, E-FC, and W-CC have equal contribution. L-QF and W-CC are guarantors.

  • Funding: This study was supported by the Program of International Science and Technology Cooperation of China (2013DFA30800), Basic Work on Special Program for Science and Technology Research (2013FY114600), National Natural Science Foundation of China (81402730), Special Program for Prevention and Control of Infectious Diseases in China (2013ZX10004218), US National Institutes of Health (1R01-AI108993), Zhejiang Province Major Science and Technology Program (2014C03039), and Quzhou Science and Technology Program (20111084). The funding bodies had no role in study design, data collection and analysis, preparation of the manuscript, or the decision to publish.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: support from the Program of International Science and Technology Cooperation of China, Basic Work on Special Program for Science and Technology Research, National Natural Science Foundation of China, Special Program for Prevention and Control of Infectious Diseases in China, US National Institutes of Health, Zhejiang Province Major Science and Technology Program, and Quzhou Science and Technology Program for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: An ethics waiver was granted and authorised under the National Emergent Public Health Events Act. According to this Act, collection of data related to H7N9 cases was an important part in epidemic analyses and subsequent control measures. Therefore, the investigation was exempt from institutional board assessment.

  • Patient consent: The family members of the two patients signed consent forms approving the investigation and its publication.

  • Data sharing: No additional data available.

  • C-FF, E-FC, L-QF, and W-CC affirm that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

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