Ecological effect of Taenia saginata in beef imported from a high prevalence area into Norway

A dynamic simulation model was used to assess the long-term effect of impor ting beef from an area with a high prevalence of Taenia saginata among catt le. The input of the model was from a Monte Carlo simulation model. The mod el predicted substantial increases in the prevalence of T. saginata in dome stic cattle and in the incidence and prevalence of infections in humans tha t would last for more than one decade even if importation of infected beef was stopped after 2 years. The results were strongly influenced by various assumptions about proportion of human carriers infected abroad. Only in a s cenario where 99% of domestic carriers are infected abroad did the simulati on results show no dramatic ecological effect of importation of the beef. I f the model's predictions are realistic, then an increase in the prevalence of T. saginata infections in cattle will be observed in and after 1999.