Stephanurus dentatus

This is the kidney worm of swine, so-called because its predilection sites include the kidneys and associated tissues - more specifically the walls of the ureter and in capsules in the peri-renal fat.

It is the only known species in the genus and is found throughout the world but is more common in warm temperate, subtropical and tropical areas. It is of particular importance where pigs are raised outdoors because its preparasitic larvae are free living and may also utilize earthworms as transport hosts. In the United States it is more prevalent in the South, particularly the southeastern states, where it is also common in feral swine.


It is a large-bodied worm with a mottled appearance because its transparent cuticle shows its internal organs. It is 2-4 cm long, has a prominent buccal capsule with teeth and males have a copulatory bursa.

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Stephanurus dentatus adult worms in situ in the perirenal fat

Stephanurus dentatus adult worms male (upper) and female (lower)

Stephanurus dentatus adult worms protruding from a ureter




Parasites and Parasitic Diseases of Domestic Animals
Dr. Colin Johnstone (principal author)
Copyright 1998 University of Pennsylvania
This page was last modified on January 24, 2000