The distribution of the 70 cases during the infant pneumonia outbreak. On 8 December 2008, the first case was observed at the Xixiang Hospital, Shaanxi Province who presented febrile symptoms. The number of similar cases increased dramatically by 9 January. By 9 February 2009, the outbreak affected a total of 70 children in the Hanzhong area. These cases were identified based on a case definition and by conducting an active epidemiology search.
Tang et al. Virology Journal 2011 8:23 doi:10.1186/1743-422X-8-23