[Fitzcarraldo]

5. SARS may exist in persons as an asymptomatic disease

These must be tracked as well.

[EternalHope]

Obviously, if all this is true, then SARS cannot be contained. (It's too soon to know for sure.)

BTW: What happens in a world wide pandemic?

[TaxRelief]

SARS may exist in persons as an asymptomatic disease. These must be tracked as well.

You are absolutely correct. One cannot build a model without complete information. There are several important factors missing from this equation. Here is a great book with all the facts, for those of you who want to panic. Here's the condensed version: Wash or sanitize hands. Keep hands off face and fingers out of noses and eyes. Wash hands. Avoid touching public surfaces.