EN
Ascaris suum is the commonest parasitic infection of pigs, with deleterious effects that give rise to the greatest economic losses in the swine industry. Popular methods of treatment with anthelmintic drugs have proved largely ineffective in reducing the incidence of swine ascariasis. We propose the use of drug-abbreviated infections to immunize young pigs. Young animals receive drug in their feed when they are continuously exposed to the infective eggs normally occurring in their surroundings. After 3-6 weeks, pigs acquire resistance that is effective against subsequent exposures to infective eggs after the drug is withdrawn.