Concern over severe acute respiratory syndrome, or SARS, continues to rise. Two weeks ago, we reported 350 cases of the disease worldwide that had resulted in 10 deaths. At the beginning of this week, the World Health Organization reported more than 2,600 cases, with 100 deaths, in 18 countries; it is spreading at a rate of 9 to 12 percent a day. The investigation into the epidemic has revealed capriciousness on the part of the virus and on the part of Chinese authorities who reverted to standard operating procedure in covering up the outbreak of an infection that now threatens individuals and national economies.

Public health officials and scientists around the world are working to identify the cause of SARS, how it is transmitted as well as a cure. They have been somewhat successful with the first, but are drawing blanks on the second and third. Although it was originally thought that the cause was a newly discovered virus, experts now believe that a combination of viruses increases virulence and infectiousness. The death rate among the infected is 3 to 4 percent, and SARS is about as contagious as influenza or Hepatitis A.

For all we do not know about SARS, we do know that it originated in Foshan, a village in Guangdong Province in southeast China. The first case occurred Nov. 16, 2002. It came to Guangzhou in January, transmitted by a shrimp salesman who was treated for pneumonia-like symptoms at three medical facilities, where he is thought to have infected 90 people. (Oddly, the man did not infect his four children.) Among them was a doctor who left for Hong Kong and stayed at the Metropole Hotel Feb. 21-22. There he is believed to have infected several people who spread the disease around the world.