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Volume 19, Number 11—November 2013


Use of National Pneumonia Surveillance to Describe Influenza A(H7N9) Virus Epidemiology, China, 2004–2013

Nijuan Xiang, Fiona Havers, Tao Chen, Ying Song, Wenxiao Tu, Leilei Li, Yang Cao, Bo Liu, Lei Zhou, Ling Meng, Zhiheng Hong, Rui Wang, Yan Niu, Jianyi Yao, Kaiju Liao, Lianmei Jin, Yanping Zhang, Qun Li, Marc-Alain Widdowson, and Zijian FengComments to Author 
Author affiliations: Chinese Center for Disease Control and Prevention, Beijing, China (N. Xiang, T. Chen, W. Tu, L. Li, Y. Cao, B. Liu, L. Zhou, L. Meng, Z. Hong, R. Wang, Y. Niu, J. Yao, K. Liao, L. Jin, Y. Zhang, Q. Li, Z. Feng); Centers for Disease Control and Prevention, Atlanta, Georgia, USA (F. Havers, M.-A. Widdowson); Centers for Disease Control and Prevention, USA/China, Beijing (Y. Song)

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Table 3

Reported PUE cases that were positive for influenza A(H7N9) virus before and after closure of live-bird markets in 3 cities, mainland China, March 30–May 3, 2013*

Location 0–6 d before closure†
1–7 d after closure†
8–14 d after closure†
p value
No. PUE A(H7N9) positive, no. (%) No. PUE A(H7N9) positive, no. (%) No. PUE A(H7N9) positive, no. (%)
Shanghai 81 11 (14) 188 4 (2) 122 1 (1) <0.001
Nanjing 7 5 (71) 0 0 1 1 (100) 0.564
Hangzhou 60 15 (25) 34 4 (12) 5 0 0.056
Total 148 31 (21) 222 8 (4) 128 2 (2) <0.001

*PUE, pneumonia of unknown etiology.
†Dates of market closures: Shanghai: April 6; Nanjing: April 8; Hangzhou: April 15, 2013.
‡χ2 test for trend for percentage of reported cases testing positive for A(H7N9).

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