Proper tests were performed and all results were negative.
"Stool examination for ova and parasites was negative. Chest radiographs revealed no abnormalities, and abdominal radiographs revealed a prominent bowel gas pattern consistent with adynamic ileus."
Furthermore...
"Examination of feces for ova and parasites is not helpful because they are not excreted in human feces."
I honestly believe they can be found, but better techniques need to be employed or they need to look HARDER for the evidence.