The Course of Taenia Hydatigena Infections in Growing Pigs and Lambs: Clinical Signs and Post-Mortem Examination

Abstract

Large White minimal disease pigs (3·5 to 18 weeks old), Welsh Mountain lambs (eight to nine weeks old), and hoggets (37 to 54 weeks old) were experimentally infected with Taenia hydatigena eggs. Pigs were given 1000 to 6000 eggs, lambs 25 000 eggs and hoggets 10 4 or 10 5 eggs. Two of the 35 pigs developed some clinical signs of infection. Metacestode burdens of the pigs post mortem were low. Differential leucocyte counts carried out on one litter of pigs during the course of infection were of little value for the diagnosis of infection. The lambs were highly susceptible to infection with four of six lambs showing clinical signs, two of which died. The hoggets appeared refractory to infection. Serum glutamate oxaloacetate transaminase and glutamate pyruvate transaminase levels became elevated in lambs, but not in hoggets, during the period of metacestode migration. Mature metacestodes remained adhering to liver surfaces as long as 133 and 92 days after infection of pigs and sheep respectively. There were more ‘white spot’ lesions on the livers of animals which had been infected over a short period of time compared with others. Such ‘white spot’ lesions will lead to liver trimming or condemnation at meat inspection.