Abstract
A motile worm, 133 mm long by 0.6 mm wide, was found in the toilet bowl of a nursing home for the aged in Kochi Prefecture, Japan, and was first suspected to be a parasite passed in the urine from an inmate. However, examination revealed it to be a postparasitic female juvenile of Mermis sp. (Nematoda: Mermithidae), a parasite of insects. It is surmised that the worm emerged from an infected insect and entered the toilet bowel. Careful identification is required for such invertebrate-parasitic and free-living helminths that may appear in the toilet bowl and be mistaken as human parasite.
Key words: Mermis sp.; Mermithidae; Nematoda; human urine; Jpan.