miércoles, 29 de abril de 2015

Transmission Potential of Influenza A(H7N9) Virus, China, 2013–2014 - Volume 21, Number 5—May 2015 - Emerging Infectious Disease journal - CDC

full-text ►

Transmission Potential of Influenza A(H7N9) Virus, China, 2013–2014 - Volume 21, Number 5—May 2015 - Emerging Infectious Disease journal - CDC





Volume 21, Number 5—May 2015

Dispatch

Transmission Potential of Influenza A(H7N9) Virus, China, 2013–2014

Adam J. Kucharski1Comments to Author , Harriet L. Mills1, Christl A. Donnelly, and Steven Riley
Author affiliations: London School of Hygiene and Tropical Medicine, London, UK (A.J. Kucharski)National Institutes of Health, Bethesda, Maryland, USA (A.J. Kucharski)Imperial College London, London (A.J. Kucharski, H.L. Mills, C.A. Donnelly, S. Riley)

Abstract

To determine transmission potential of influenza A(H7N9) virus, we used symptom onset data to compare 2 waves of infection in China during 2013–2014. We found evidence of increased transmission potential in the second wave and showed that live bird market closure was significantly less effective in Guangdong than in other regions.
From February 19, 2013, through April 22, 2014, a total of 429 cases of influenza A(H7N9) virus infection in humans in China were reported and occurred in 2 outbreak waves. During the first wave in spring 2013, live bird markets were closed in several parts of China (1,2); these market closures substantially reduced the risk for infection in affected regions (3). During a second wave in autumn 2013 (4), markets were again closed in some provinces (57). Analysis of the largest clusters of subtype H7N9 virus infection in 2013 suggested that the basic reproduction number (R0, the average number of secondary cases generated by a typical infectious host in a fully susceptible population) was higher in some clusters than in others (8,9), although the absence of sustained transmission implied that R0 was less than the critical value of 1. To determine the transmission potential of influenza A(H7N9) virus in the first and second waves in 2013, we compared symptom onset data. We also measured the extent to which market closures in 2014 reduced spillover hazard (i.e., risk for animal-to-human infection).

Dr. Kucharski is a research fellow in infectious disease epidemiology at the London School of Hygiene and Tropical Medicine. His research focuses on the dynamics of emerging infections and how population structure and social behavior shape disease transmission at the animal–human interface. Dr. Mills is a postdoctoral research associate in the Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London. Her research includes examination of human mobility patterns and their influence on disease transmission and the analysis of emerging epidemics.

Acknowledgment

This work was funded by the Wellcome Trust (project grant 093488/Z/10/Z); the Medical Research Council (United Kingdom, project grant MR/J008761/1; Fellowship MR/K021524/1); National Institute for General Medical Sciences (United States, MIDAS U01 GM110721-01); the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 278433-PREDEMICS; the Fogarty International Center (United States, R01 TW008246-01); and the Research and Policy for Infectious Disease Dynamics program also from Fogarty International Center with the Science and Technology Directorate, Department of Homeland Security.

References

  1. Li QZhou LZhou MChen ZLi FWu H, et al. Epidemiology of human infections with avian influenza A(H7N9) virus in China. N Engl J Med.2014;370:520–32. PubMed
  2. Murhekar MArima YHorby PVandemaele KAVong SZijian F et al. Avian influenza A (H7N9) and the closure of live bird markets. Western Pac Surveill Response. 2013;4:4–7. PubMed
  3. Yu HWu JTCowling BJLiao QFang VJZhou SEffect of closure of live poultry markets on poultry-to-person transmission of avian influenza A H7N9 virus: an ecological study. Lancet2014;383:5418DOIPubMed
  4. Chen EChen YFu LChen ZGong ZMao H, et al. Human infection with avian influenza A (H7N9) virus re-emerges in China in winter 2013. Eurosurveill. 2013;18:pii:20616.
  5. Lau MWei L. Guangzhou begins trial ban of live poultry sales after H7N9 wet market tests. South China Morning Post. 2014 May 5; News/China/Health.
  6. Huixin W. Some live poultry markets closed permanently. Shanghai Daily. 2014 Feb 24.
  7. Wu PJiang HWu JTChen EHe JZhou H, et al. Poultry market closures and human infection with influenza A(H7N9) virus, China, 2013–14. Emerg Infect Dis. 2014;20 1891-4.
  8. Chowell GSimonsen LTowers SMiller MAViboud CTransmission potential of influenza A/H7N9, February to May 2013, China. BMC Med.2013;11:214 . DOIPubMed
  9. Kucharski AJMills HLPinsent AFraser CVan Kerkhove MDDonnelly CA, et al. Distinguishing between reservoir exposure and human-to-human transmission for emerging pathogens using case onset data. PLoS Curr.2014;6:pii:ecurrents.outbreaks.e1473d9bfc99d080ca242139a06c455f.
  10. Liu TBi ZWang XLi ZDing SBi Z, et al. One family cluster of avian influenza A (H7N9) virus infection in Shandong, China. BMC Infect Dis.2014;14:98.
  11. Hu JZhu YZhao BLi JLiu LGu KLimited human-to-human transmission of avian influenza A(H7N9) virus, Shanghai, China, March to April 2013.Euro Surveill2014;19:20838.PubMed
  12. Xiao CLi KBChen ZQDi BYang ZCYuan JTransmission of avian influenza A(H7N9) virus from father to child: a report of limited person-to-person transmission, Guangzhou, China, January 2014. Euro Surveill2014;19:20837.PubMed
  13. Gilbert MGolding NZhou HWint GRWRobinson TPPredicting the risk of avian influenza A H7N9 infection in live-poultry markets across Asia.Nat Commun. 2014;5:4116 .DOIPubMed
  14. Chen ZLi KLuo LLu EYuan JLiu H, et al. Detection of avian influenza A(H7N9) virus from live poultry markets in Guangzhou, China: a surveillance report. PLoS ONE. 2014;9:e107266.

Figures

Table

Technical Appendix

Suggested citation for this article: Kucharski AJ, Mills HL, Donnelly CA, Riley S. Transmission potential of influenza A(H7N9) virus, China, 2013–2014. Emerg Infect Dis. 2015 May [date cited]. http://dx.doi.org/10.3201/eid2105.141137
DOI: 10.3201/eid2105.141137
1These authors contributed equally to this article.

No hay comentarios:

Publicar un comentario