Dracunculus insignis, also known as the Guinea worm, is found mainly in the subcutaneous connective tissues of the legs of raccoons, mink, and other animals, including dogs and cats, in North America and possibly other parts of the world. The females (≥300 mm long) are much longer than the males (~20 mm). They produce ulcers in the skin of their host, through which their anterior end is protruded on contact with water. Females produce characteristic long, thin-tailed larvae. Water fleas (Cyclops sp) are the intermediate host in which infective larvae develop. Dogs become infected through ingestion of contaminated water or a paratenic host (frogs).
Subcutaneous, serpentine, inflammatory tracts and nonhealing, crater-like, edematous skin ulcers are seen. Infections are rare but are occasionally found in animals that have been around small lakes and bodies of shallow, stagnant water. Treatment is by careful, slow extraction of the parasite. Administration of miridazole or benzimidazole compounds may be useful.
D medinensis, the Guinea worm of parts of Africa, Asia, and the Middle East, although primarily a parasite of people, is also found in dogs and other animals.