The parasitic life-cycle of the swine kidney worm Stephanurus dentatus Diesing

Abstract

Third-stage larvae of S. dentatus exsheath in and invade the tissues of a variety of animals. After oral infection of guinea pigs and pigs, third-stage larvae migrate principally from the small and large intestine via the portal blood, mesenteric lymphatics, and, to a lesser degree, the peritoneal cavity. Large numbers of larvae invade the liver, and it was shown that some larvae can escape from the liver and lungs. After infection via the skin, third-stage larvae migrate mainly to the lungs. There was evidence that some larvae undertake a tracheal migration from the lungs and subsequently penetrate the digestive tract. The third moult occurs in a variety of tissues, and by using transplantation techniques, it was shown that fourth-stage larvae are capable of extensive migration. The liver is the most suitable organ for the development of fourth-stage larvae and immature adult worms. The migratory behaviour of mature adult worms was studied by transplanting adult worms into the peritoneal cavity. One patent infection was established using this technique, but it appeared that most worms migrated randomly throughout the carcass.