The outbreak of SARS (Severe Acute Respiratory Syndrome) that originated in China is, with "95–97% certainty," caused by a completely new type of coronavirus, according to Julie Hall, who is responsible for the World Health Organization's Global Alert, Response and Operations Network.
The new virus diverges by 50–60% from the three known groups of coronavirus, but that is typical of the variation between coronavirus groups, according to Stephan Günther of the Bernhard Nocht Institute of Tropical Medicine in Hamburg. Günther works with Christian Drosten, who along with researchers in several other laboratories has identified the coronavirus in SARS patients.
The coronavirus has the largest known genome of all RNA viruses, and frequently recombines.
Two other viruses, both paramyxoviruses, seem also to be...