Bioscope '03

by Dr. Barbara Price

          It was at this time last year that Severe Acute Respiratory Syndrome (SARS) emerged in China and exacted a significant financial toll in China, Hong Kong, Taiwan, Singapore and Canada. There were more than 8000 cases and 774 deaths attributed to SARS. The virus was identified as the coronavirus, SARS-CoV, which may have evolved from a similar coronavirus in civets and raccoon dogs or may be in an animal reservoir. (The role of animals in the transmission of SARS-CoV to humans is still under investigation.) The world health organizations were especially critical of China's actions in reporting and containing the disease. Each of these countries is determined not to let that happen again, either in their country or in China. Each country has rapidly developed the capability to detect and confirm the presence of the virus and antibodies. For example, in Singapore the Defense Science Organization National Laboratory's Biological Defence Verification Team is a key member of the SARS Clinical Consortium, which confirmed the presence and absence of SARS in a variety of samples using PCR techniques during the early part of 2003. Similar groups were formed in each of the other countries.

          WHO has called for a calibrated response to monitor for another outbreak of SARS. This response is tailored to avoid laboratories and hospital isolation wards being overwhelmed with testing. A second blood test from a second laboratory would be needed to confirm the presence of SARS-CoV. WHO's experts divided the world in three zones, reflecting the likelihood of increased risk of infection and re-emergence. The first zone is southern China and possibly Hong Kong, the re-emergence zone, and WHO recommends automatically testing any case of atypical pneumonia for SARS-CoV; atypical pneumonia is one of the first clinical signs. In the second zone, nodal areas, primarily the rest of China, Taiwan and Singapore, the testing for SARS-CoV would occur only if there were a cluster of cases with atypical pneumonia. The rest of the world is considered a low risk area and SARS-CoV testing would be required as a "last resort". The biggest problem is in resource-poor areas, where chest x-ray equipment to diagnose pneumonia is not available. Other concerns include the role of aerosolization, which may be the reason some more well equipped hospital had a greater amplification of SARS than some hospitals using less sophisticated techniques. Airborne transmission of SARS-CoV is not thought to be an important infection route, but if it were, the measures to control airborne transmission are more resource intensive. And, of course, the possibility of laboratory infection, such as happened in Singapore from a sample inadvertently contaminated with SARS-CoV, requires adequate safety controls.

          In May 2003, the WHO held a global meeting on the epidemiology of SARS and published its consensus report October 22, 2003. http://www.who.int/csr/sars/en/WHOconsensus.pdf.