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
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.
Stephanurus dentatus adult worms
in situ in the
Stephanurus dentatus adult worms male (upper)
and female (lower)
Stephanurus dentatus adult worms protruding from a