Linking the cases will require identification of the agent causing SARS.

Scientists are still trying to prove that this coronavirus causes SARS.

It is likely to take weeks more to determine which virus, singly or in combination, actually causes SARS.

In 2003, the chip technique confirmed that a previously unknown coronavirus caused SARS.

Doctors believe a virus causes the disease, severe acute respiratory disease, or SARS.

But in the absence of a diagnostic test, the network is working on the assumption that the coronavirus causes SARS.

She said she was keeping an open mind about even if a virus causes SARS.

But the campaign had to begin with a simple, essential question: what exactly was causing SARS?

She has studied coronaviruses for more than 20 years, and is now turning her attention to the one believed to cause SARS.

Health officials do not know what causes SARS.