Experimental transfer of Ascaris suum from donor pigs to helminth naive pigs

The difficulties in experimentally establishing patent intestinal infections with the pig large roundworm Ascaris suum make transfer of adult or larval stages a potentially important method of inducing this infection. Adult worms and 10-day-old larvae were transferred by stomach tube to untreated pigs and pigs treated with the gastric acid pump inhibitor omeprazole, as well as surgically directly into the small intestine of pigs. Transfer of adult worms resulted in patent infections with comparable worm survival rates in all 3 recipient groups but with a nonsignificant decrease in egg production after transfer to untreated pigs. Thus, it is possible with oral transfer of adult worms to achieve infections with more or less known numbers and sexes of the parasites, as well as producing patent infections in hosts that have never experienced a hepato-tracheal migration. Whereas the orally transferred 10-day-old L3/L4 larvae did not establish well, surgical transfer of larvae to helminth-naive recipient pigs resulted in high recovery rates 1 wk after transfer in 3 out of 5 pigs.