Epidemiological features and spatio-temporal evolution in the early phase of the Beijing H1N1 epidemic

Influenza A H1N1 has spread around the world with a horrifying speed. China has the largest population in the world, which makes China more vulnerable to Influenza A H1N1. Using the epidemiological survey data concerning 744 H1N1-infected patients in Beijing during May 13, 2009 to August 15, 2009, this paper presents the epidemiological features. Based on 94 H1N1 cluster outbreak events, we studied the pattern of spatio-temporal evolution during the early phase of Beijing 2009 H1N1 epidemic. We also compared the spatial transmission network of the early Beijing H1N1 epidemic with that of the Beijing 2003 SARS epidemic. The results indicate that both networks are consistent from the point of view of structure. The triangle zones of the city central districts (including Dongcheng, Xicheng, Chongwen and Xuanwu) - Chaoyang District - Haidian District are the key places to control H1N1 epidemic. With the limit of emergency resources, efforts should be made on public health to prevent these zones from the spread of H1N1 Influenza A H1N1 infection. The emergency control measures implemented in Beijing are effective and timely.