Helminths are parasitic worms. Dracunculus insignis is a species of roundworm found mainly in the connective tissue beneath the skin of the host animal's legs. They are known to infest raccoons, minks, and other animals in North America. Female worms can reach more than 1 foot (300 millimeters) in length. Male worms are tiny in comparison, approximately 0.8 inches (20 millimeters) long. These worms are rare in cats, but they are occasionally found in cats that have been around small lakes and bodies of shallow, stagnant water.
These worms can produce skin ulcers on their hosts. When the ulcers touch water, the worms stick their heads out of the wounds to lay their long, thin-tailed larvae. The larvae then develop inside of another host, the water flea. Cats can become infected by drinking contaminated water or eating an infected animal, such as a frog.
Signs of worm infestation include snake-like, swollen tracks under the skin and crater-like red ulcers on the skin’s surface. Treatment requires careful extraction of the worm by a veterinarian.