A multicentre collaboration to investigate the cause of severe acute respiratory syndrome.

Severe acute respiratory syndrome is a new disease in human beings, first recognised in late February, 2003, in Hanoi, Vietnam. The severity of the disease, combined with its rapid spread along international air-travel routes, prompted WHO to set up a network of scientists from 11 laboratories around the world to try to identify the causal agent and develop a diagnostic test. The network unites laboratories with different methods and capacities to rapidly fulfil all postulates for establishing a virus as the cause of a disease. Results are shared in real time via a secure website, on which microscopy pictures, protocols for testing, and PCR primer sequences are also posted. Findings are discussed in daily teleconferences. Progress is further facilitated through sharing between laboratories of samples and test materials. The network has identified a new coronavirus, consistently detected in samples of SARS patients from several countries, and conclusively named it as the causative agent of SARS; the strain is unlike any other known member of the genus Coronavirus. Three diagnostic tests are now available, but all have limitations.