Health officials are scrambling to find the source of an E. coli outbreak that has killed a little girl and sickened more than a dozen people in 6 southern states.

Officials believe all the victims contracted the same strain of E. coli, which produces a deadly toxin and can cause violent reactions, kidney damage, even death.

The largest cluster is in Atlanta where five cases have been discovered.

Experts don't know the cause of the outbreak, but suspect it came from under- cooked meat.

The period from April through September is known as "high-prevalence season" for E. coli because outdoor barbeques increase the risks of bacteria in food.