Five people have died and nearly 200 from about three dozen states have been sickened by E. coli in a growing outbreak that has so far stumped federal investigators. The Centers for Disease Control and Prevention announced the tally Friday, more than two months after the first illnesses occurred in mid-March. Although investigators have determined that the E. coli came from contaminated romaine lettuce grown in Arizona's Yuma region near the border with Southern California.

A majority of those who have been affected come from California, where one death was reported, and Pennsylvania. The four other deaths were reported in Arkansas, Minnesota and New York, according to the CDC. E. coli is a type of bacteria found in undercooked beef, raw milk, soft cheeses made from raw milk, raw fruits and vegetables, and contaminated water. Most E. coli bacteria is not harmful, but one type known as E. coli O157: H7 produces a toxin called Shiga, which destroys red blood cells, and causes kidney failure and bloody diarrhea. Other kinds of E. coli cause urinary tract infections, respiratory illness and pneumonia.

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