What is the difference between influenza and sars?

2 different viruses: SARS or severe acute respiratory syndrome was an explosive outbreak of adult respiratory distress syndrome that started in Hong Kong in 2003. Within weeks of the outbreak it was determined that SARS was caused by a novel coronavirus. It was found that this virus infected civets and horseshoe bats which were the zoonotic natural reservoirs. Influenza virus is entirely different.

Totally different: While both diseases affect the lung, they are caused by 2 distinct viruses. Influenza is a common yearly seasonal infection. Sars was a rare onetime event which isn't likely to recur.