JOHNSON CITY, Tenn. (WJHL) — Four elementary schoolchildren remain seriously ill with complications more than two weeks after exposure to E. coli during Sept. 26 and 27 field trips to the Appalachian Fairgrounds, a regional health official confirmed Friday.

Dr. David Kirschke of the Northeast Regional Health Office (NEHRO) said in a statement that a total of seven children had been hospitalized as a result of exposure to Shiga-toxin-producing E. coli. Elementary classes from both Washington and Sullivan counties visited the fairgrounds.

“These illnesses occurred after some classes visited an animal exhibit,” the statement said. Officials from both NEHRO and the Sullivan County Health Department are investigating the cases of illness.

The statement included links to Centers for Disease Control information on both E. coli and staying healthy at animal exhibits.

This is a developing story.