In the second week of March of this year, the World Health Organization (WHO) received reports of >150 cases of acute respiratory illness associated with pneumonia 1. The majority of these cases were from the South-East Asian countries of China (including Hong Kong), Vietnam, Indonesia, the Philippines and Singapore. The appearance of many cases over a short time period, the absence of a clear causative pathogen, the apparent spread between countries and the death of some cases led to the issue of a global alert. The subsequent increase in the number of cases in this region and the identification of possible cases in distant countries, such as Germany, Canada and the UK (table 1⇓), increased alarm that a transmissible agent was causing an epidemic that was being further spread by easy access to air travel. Alarm was fed by the prior report of the deaths of two members of a family from Hong Kong with H5 N1 influenza virus infection presumed to have been acquired from birds on the Chinese mainland and the reporting of an earlier outbreak of respiratory infection of unknown cause in the Guangdong Province in China that had affected >300 individuals of whom three died. View this table: Table 1 Cumulative number of reported cases of severe acute respiratory syndrome (SARS) to March 29 2003 The WHO took a pivotal role in the investigation of the outbreak, with the development of a case definition for severe acute respiratory syndrome (SARS) (fig. 1⇓) 1. Global Outbreak Alert and Response teams assisted in outbreak management and the collection of epidemiological and clinical data to improve the understanding of the condition. A …