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Project facts

Project manager

Porträtt av Per Wallgren

Main applicant



Swedish University of Agricultural Sciences


2017 - 2021

Field of research


Occurence of internal parasites end resistance to anthelminitics in Swedish pig herds

Internal parasites are common in pigs worldwide, but apparent clinical symptoms are rare or difficult to quantify. Still, mass infestation compromise productivity and lead to reduced animal welfare and financial losses. The prevalence of internal parasites in conventional Swedish pig herds has not been thoroughly investigated since the 1980ies. Since then, pig production in Sweden has undergone major structural changes with larger production sites and sows kept lose during farrowing, lactation and pregnancy.

Consequently, the historical knowledge is no longer applicable, but routine preventive deworming strategies are still commonly based on the findings from the 1980ies. Although it not is known if pig parasites in Sweden have acquired resistance to anthelmintic substances, routine deworming strategies based on knowledge that is out of date might increase the risk for development of anthelmintic resistance.

This project will document the occurrence of internal parasites in Swedish conventional pig herds and deworming practices applied today. Also the efficacy of anthelmintic drugs will be studied, and the recommendations for anthelmintic treatments will be updated. With the aim of limiting deworming to truly infected pigs, the project will also scrutinize if routine deworming can be replaced by strategic diagnostic fecal samplings, after which only confirmed infected animals will be dewormed.

Last updated : 2022-01-02