Oesophagostomum dentatum and Trichuris suis infections in pigs born and raised on contaminated paddocks

Summary

SUMMARY
Transmission of Oesophagostomum dentatum and Trichuris suis was studied in outdoor reared pigs. Six farrowing paddocks were naturally contaminated in May to mid June 2001 by experimentally infected seeder pigs. Early July, 1 sow farrowed on each paddock and starting week 3 post partum (p.p.) the offspring was slaughtered serially every 2 weeks for recovery of O. dentatum and T. suis. Faeces was collected regularly for parasite egg counts and acid-insoluble ash (AIA) content as an indicator for geophagy. Weaning took place week 7 p.p. by removing the sow. Paddock infection levels were estimated in mid June (O. dentatum) and late November (O. dentatum and T. suis) using helminth naïve tracer pigs. Soil and vegetation samples were collected regularly. Despite a high initial contamination by the seeder pigs, O. dentatum paddock infectivity was negligible to low throughout the raising of the experimental piglets, which had a slow accumulation of nodular worms ending with a mean of 422 worms/pig week 19 p.p. As only few eggs developed to infectivity overall T. suis transmission was minimal. The first T. suis were recovered week 11 p.p. and the highest mean burden of 21 worms/pig was recorded week 19 p.p. The experimental pigs had high faecal levels of AIA though it was decreased from 53 % in 3 weeks old piglets to 15 % in 19 weeks old pigs. The results are discussed in relation to the biological characteristics of the 2 parasites and their occurrence in organic pig production.