31 cases of infant botulism in 15 states tied to recall. See map.

Cases of infant botulism tied to the ByHeart infant formula recall have nearly tripled across 15 states since the recall was first announced less than a month ago.

U.S. Food and Drug Administration reported 13 cases across 10 states when the recall was first announced on Nov. 8. Since then, the number has jumped to 31 cases across 15 states, according to the latest update on Nov. 19.