Serodiagnosis of infections of pigs with Stephanurus dentatus

A serological survey of 135 pigs over 7 months old, some of which had liver and renal lesions in the presence ofStrephanurus dentatus, was undertaken for the presence of antibodies to S. dentatus. Only one sample gave a positive gel immunodiffusion reaction with crude whole worm extracts and none with immunoelectrophoresis. Oral inoculation of pigs with 1200 or 2000 L3 resulted in a specific reaction of anodal lines on immunoelectrophoresis from Day 37, and with double diffusion up to 4 specific lines were produced beginning from Day 43–53 using adult and juvenile antigens. Juvenile antigens gave more intense lines. Serological responses remained positive until 76–80 days post-infection. At necropsy infected pigs had fibrotic lesions in livers and portal thrombi containing larval S. dentatus even after 270 days. It is concluded that immunodiffusion and immunoelectrophoresis have limited usefulness in serodiagnosis of naturally occurring stephanuriasis.