NEW ALBANY, Ind. (AP) — An E. coli outbreak that sickened about a dozen Floyd County school children last fall likely began when a single child had contact with the bacteria, possibly by touching a goat or cow, state health officials said.

Those findings are part of a report by the Indiana State Department of Health that’s expected to be released in a week to 10 days, said Floyd County health officer Dr. Tom Harris, who reviewed the report last week.

During the outbreak, there were 15 confirmed or probable cases of E. coli infection, which can cause diarrhea, cramps and — in severe cases — kidney damage.

The cluster of Floyd County cases began in September when four Galena Elementary School students were initially diagnosed.

According to the state report’s findings, one student inadvertently brought the infection into the Floyds Knobs school, perhaps after contact with a cow or goat.

Livestock are reservoirs for the bacteria but don’t display symptoms of the illness.

In all, 10 E. coli cases were confirmed by bacterial culture among children attending Galena or their siblings. The mother of a student who attended a play group with infected students also was confirmed to have had the illness, and one other adult is listed as a probable case.

Harris said an unusual aspect of the outbreak is that about half those confirmed to have the illness suffered kidney damage. Typically, no more than 9 percent of people found to be infected with the E. coli strain involved in the Floyd County cases get such damage, Harris said.

Kidney damage can result if people are treated with antibiotics for other illnesses around the time of an E. coli infection, he said.

Three of the infected Floyd County children had taken antibiotics. But Harris said that does not explain why so many had kidney damage. Three other children were determined to have been infected because they had the type of kidney damage caused by the bacteria, he said.

All the students who became ill are back at school.