The outbreak may have affected a dozen or so children in the day-care center, but only five developed life-threatening symptoms, such as hemolytic uremic syndrome or kidney failure, that required hospitalization. An additional child, also seriously affected, did not attend the day-care center.
Federal privacy laws shield the identities of the children, where they were hospitalized and their medical conditions upon release from the hospital.
But, local officials say all of the children have recovered from their bouts with the bacteria, identified as E. coli 0157H7. E. coli bacteria are found in the intestines of some animals, such as cattle. The presence of the bacteria in water can indicate fecal pollution.
Dan Pekarek, director of the Joplin Health Department, said the general public was not alerted to the outbreak because local health officials believed it was isolated and confined to the day-care center. If it had occurred in connection with a restaurant, the public would have been notified, he said.
The parents of children attending the day-care center were notified that a cluster of cases had developed, and that they should watch for certain symptoms involving their children. Local hospitals and pediatricians also were notified. A bloody stool is the most common symptom.
Pekarek said the investigation revealed no connection between the outbreak and the operation of the day-care center. After the outbreak, inspections of the center were increased.
Two of the children who became ill were from near Carthage. One of them, Pekarek said, was enrolled in the day-care center. That child was the index case who exposed the bacteria to the other children at the center.
But, the investigation showed that the other child from Carthage was not enrolled at the day-care center and did not have any connection to the index case. Pekarek said officials have been unable to link that child to an E. coli source.
Five children at the day-care center developed serious symptoms from the exposure. Others at the center, fewer than a dozen, fell ill but recovered. The more serious cases were confirmed through lab tests as E. coli.
"Through our interview process, we learned that some children had symptoms that could have been consistent with E. coli," Pekarek said. "It is not abnormal to be unable to confirm through a stool sample."
At the same time the cases were developing in May, the Jasper County Health Department received notice from health officials in St. Louis that a child there, who had traveled through Jasper County in May, had been diagnosed with an E. coli infection.
Tony Moehr, director of the Jasper County Health Department, said the child from St. Louis spent a brief period of time in Jasper County and could not be connected to the children from the Carthage area.
Pekarek said the investigation is continuing. No additional cases have surfaced since the end of May. The disease has a short incubation period of three to four days.
"As E. coli outbreaks go, this was a large cluster," he said. "We probably see a case of E. coli a year. This was certainly an unusual event."