Max, a 6-year-old neutered male Jack Russell terrier, developed malodorous diarrhea after a weekend visit to a sheep farm.
History. Max had no prior medical history.
Physical Examination. Max's physical examination was unremarkable. His attitude and behavior were normal. The owner brought along a sample of foul-smelling liquid feces. A centrifugal fecal flotation examination was performed, and the technician reported the presence of coccidia, roundworms, and hookworms. The veterinarian reviewed the slide (Figure 1) and decided to send the remaining fecal sample to a reference laboratory for a second opinion.
Diagnosis: Fecal Artifacts
Fecal material often contains artifacts designated as pseudoparasites and spurious parasites. Pseudoparasites are nonparasitic material that looks parasitic. Common pseudoparasites include plant material (Figures 3 and 4), pollen grains, and free-living arthropods (Figure 5). Spurious parasites are true parasites of one species found in the feces of another species because of coprophagy or predation. In this case, both a pseudoparasite and spurious parasites were present, most likely from the ingestion of sheep manure. Ruminant coccidia oocysts and nematode parasite eggs in the manure are passed undamaged through the gastrointestinal tract. Technical staff trained to recognize only small animal parasites will understandably identify these eggs and oocysts as canine parasites. The structure that looks like a Toxocara egg is a pseudoparasite.
Figure 3. Plant hairs—long, cylindrically shaped structures—are very common fecal artifacts. Although they resemble larvae, they lack organized internal structures. A small, oval-shaped Eimeria oocyst is present in the corner (original magnification ¥400)