People in at least 14 states caught a nasty strain of E. coli from tainted onions used in McDonald's Quarter Pounders, though the immediate danger has likely now passed.

Illnesses linked to slivered onions on McDonald's Quarter Pounder burgers expand to 14 states, federal officials say.

A deadly E. coli outbreak connected to slivered onions served in McDonald's Quarter Pounder hamburgers across the country has sickened at least 104 people, federal health officials said.