Medical Editors: Barbara K. Hecht, Ph.D. and Leslie J. Schoenfield, M.D., Ph.D.
Today (April 16, 2003), the final piece of proof was obtained indicting a new coronavirus as the cause of SARS (severe acute respiratory syndrome). This last piece of proof came from experiments done in monkeys at Erasmus Medical Center in Rotterdam, the Netherlands. The monkeys that were experimentally infected with the new coronavirus developed a lung (pulmonary) disease essentially identical to SARS.
This remarkable feat fulfills Koch's postulates (requirements) that are necessary to prove the cause of an infectious disease. (Robert Koch was a German physician, a founding father of the field of bacteriology, and a recipient of the Nobel Prize for Medicine in 1905.) These enduring postulates stipulate that to be the causal agent, a disease-causing agent (pathogen) must meet four conditions. It must:
- Be found in all cases of the disease.
- Be isolated from the infected person (host) and grown in the laboratory in pure culture.
- Reproduce the original disease when introduced into a susceptible host.
- Be found in the experimental host so infected.
Less than a week ago, the identity of the SARS virus was first revealed to be a novel coronavirus, a virus never before encountered in humans. This revelation came in two reports simultaneously released by The New England Journal of Medicine. These reports, which appeared on April 10, were from the Centers for Disease Control (CDC) in Atlanta and from Hamburg, Germany.
Indeed, it was just over a month ago that the World Health Organization (WHO) on March 12 issued a global alert regarding SARS. At that time, the WHO set up a network of laboratories in Canada, France, Germany, Hong Kong, Japan, the Netherlands, Singapore, UK, and the USA. Two laboratories in mainland China also have joined this effort.
The extraordinary speed with which this virus was identified is the result of the close international collaboration of 13 laboratories from these 10 countries. While many lines of evidence over the last several weeks have found strong associations between this virus and the disease, the final confirmation came today with the monkey experiments in Rotterdam.