Scientists have definitively identified the cause of Severe Acute Respiratory Syndrome, or SARS, as a new form of the coronavirus, the World Health Organization announced April 16.

“The pace of SARS research has been astounding,” said David Heymann, executive director of the WHO Communicable Diseases Program. “Because of an extraordinary collaboration among laboratories from countries around the world, we now know with certainty what causes SARS.” Disaster News Network In case you were wondering, identification of an infectious agent is not trivial. There are specific criteria, codified by famous pathologist Koch in 1882 and now known as Koch’s Postulates, to establish that a specific organism causes a specific illness. The organism must: (a) be found regularly in instances of the disease, (b) grow out when infected body fluids are inoculated onto a culture medium, (c) cause the disease when the cultured organisms are introduced into a laboratory animal, and (d) be recoverable and culturable from lesions in the diseased test animal. A more modern molecular modification of Koch’s postulates links a disease not to the presence of the organism but its molecular traits, e.g. surface antigens or identifiable portions of the organism’s genome. Establishment of the fact that a given organism causes a disease is the sine qua non for generating diagnostic tests for the disease, for precise case definition, for developing vaccines, population screening efforts, and ultimately specific therapies.