“We were able to show that in the first 10 days of the infection, SARS coronavirus targets specific cells in the respiratory tract leading to damage of these cells and activation of special inflammatory cells in the lung.”

During the early weeks of the SARS outbreak there was intense interest as to why this novel coronavirus was causing such severe problems in the large number of affected patients. In particular, clinicians and researchers wanted to know what disease pattern was present in the lung, as this would affect their treatment protocols. Our paper was the first to describe in detail the histological appearances of the SARS coronavirus pneumonia, and in particular to look at the types of inflammatory cells present within the lung.

Surprisingly, most of the methods were those available to the standard laboratory—histopathology, immunohistochemistry, electron microscopy, and PCR. Our paper was unique because of the close networking of hospitals in Hong Kong, through which we were able to pool together the findings from a number of these hospitals in a short period of time and also to disseminate this information rapidly to other researchers in the field throughout the world. It must be remembered that at the time of the outbreak the infectivity of the virus was not well established and the pathologists who performed the autopsies to obtain the research material performed a valuable service knowing there was a potential for possible infection.

We were able to show that in the first 10 days of the infection, SARS coronavirus targets specific cells in the respiratory tract leading to damage of these cells and activation of special inflammatory cells in the lung. This damage to the alveolar results in the patients requiring ventilator therapy, which after 10 days can lead to a condition called "organizing diffuse alveolar damage." The significance of these findings is that if appropriate therapy is to be given, it should be instituted within the first 10 days in order to minimize the damage to the cells and hopefully to avoid the long-term sequelae of organizing diffuse alveolar damage.

I have spent a number of years investigating how viruses interact with cells in the human body. For the past couple of years this involved the avian influenza viruses. When the SARS outbreak occurred, we initially thought that this was the beginning of another avian influenza outbreak in humans and so I was asked to investigate the tissues from some of the early cases. Our investigations revealed that this outbreak was not due to influenza but a new agent that had not been identified in the laboratory. I think that the success of our investigations resulted from the fact that we had a team comprised of experts in various fields—virology, infectious disease, epidemiology, and pathology that were already established and close knit.