Health officials are investigating a mysterious and scattered outbreak of the E. coli bacteria linked to 14 illnesses and one death.
The Centers for Disease Control and Prevention said no form of contaminated food or other cause has been identified in the illnesses, which occurred in April and May. They are spread among six states.
Three people were hospitalized. One - a child in the New Orleans area - died last week.
The outbreak strain is E. coli 0145, a dangerous but not well-known type of bacteria. The strain was fingered in a 2010 outbreak that sickened more than two dozen people in at least five states.