When the news of an unusual pneumonia occurring in the Guangdong province of southern China reached Hong Kong, the health authorities in Hong Kong were concerned about this "atypical pneumonia," as it was then called, in adjoining Guangdong and its potential for spread into Hong Kong. Our research group based at the University of Hong Kong had a particular interest in human respiratory viral infections in general and influenza in particular, and because we also provide a clinical diagnostic virology service to the Hospital Authority of Hong Kong, we became involved in unraveling the cause. As with most discoveries in modern times, this was a collaborative effort between the University of Hong Kong, the Queen Mary Hospital, the Hospital Authority and the Department of Health, within the Hong Kong SARS. In addition, in view of the global public health threat posed by SARS, by mid-March, we became part of the W.H.O. (World Health Organization) coordinated virtual network of laboratories set up to identify the etiology of SARS, and thereby part of the global network in the fight against SARS.

The key information required to control the spread of a new emerging infectious disease includes understanding how it spreads, identifying the most effective means of interrupting its transmission, and defining the most appropriate treatment for the disease. Identifying the microbe that causes the disease provides the scientific underpinning for all these questions. It allows laboratory tests to be developed to precisely diagnose the disease, provides information on how it is transmitted, allows identification of drugs that can be used to treat the disease, and, in the longer term, allows the development of vaccines and other interventions that can be used to control its spread. By March 2003, a number of microbes were being proposed as the causative agents of SARS. Our work, and independently that of two other research groups at the Centers for Disease Control in the USA and in Germany, provided strong evidence that SARS was caused by a novel coronavirus. This information immediately led to diagnostic tests for the disease. It provided the unexpected understanding that the virus was found not just in the respiratory tract (as expected in a pneumonia) but that it was also found in the feces, pointing to the possibility that infected feces may also spread the disease. Such transmission appears to have occurred in one of the big community outbreaks of the disease in Hong Kong. The isolation of the causative agent also showed that the virus was unusually stable in the environment, explaining how some of the transmission events may have occurred.

The identification of the agent was followed by the unraveling of its full genome, a task completed in a matter of weeks. Subsequently, the identification of the drugs that can be used to treat SARS followed, and more recently, vaccine development is underway. The identification of this novel coronavirus affecting humans led to the conclusion that it was an animal virus that recently transmitted to humans. This hypothesis has subsequently been confirmed. The speed of many of these developments was facilitated, especially in the early stages, by an unprecedented global collaborative effort coordinated by the W.H.O., highlighting the need for global partnership for combating emerging infectious diseases.

Prof J.S.M. Peiris
Department of Microbiology
The University of Hong Kong
Pokfulam, Hong Kong

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