As if the flu outbreak isn't bad enough, the Centers for Disease Control says a new strain of norovirus has reached the U.S. from Australia. The CDC says the bug accounted for 58% of last month's 'stomach flu' cases, causing nausea, 'forceful' vomiting, diarrhea and abdominal pain.

This morning on "Early Start," CNN's Elizabeth Cohen explains what makes the Sydney 2012 virus so bad.