Report of spores of Henneguya salminicola (Myxozoa) in human stool specimens: possible source of confusion with human spermatozoa.

The spores of Henneguya salminicola, a common tissue parasite of salmonid fishes in the northern hemisphere, were observed in stool specimens from two different patients with diarrhea. The spores' superficial resemblance to human spermatozoa resulted, in one instance, in an incorrect report, leading to suspicion of sexual abuse. H. salminicola spores and human spermatozoa can be differentiated on the basis of size, morphology, and staining characteristics. Laboratory personnel who perform microscopic examinations of stool specimens for ova and parasites should be aware that spores of H. salminicola may be seen from time to time.