As of July 16, 14 children and 14 adults had been affected, Walls said, adding that she expected that number to grow since the organisms are spread by hand contact.
“Now some of the parents are sick,” she said.
Walls said initial tests confirmed three culprits: giardiasis, cryptosporidiosis and norovirus, all of which cause gastrointestinal illness.
One reported case came from Delaware County, Walls said, but the girl had been taking swimming lessons at West Chester University.
Walls said county officials learned through a conference call with the Centers for Disease Control that a “multi-organism event” is not an uncommon problem in a pool or lake, even though county officials had not experienced it.