INVESTIGATIONS ON TRICHINOSIS IN SLAUGHTE R ANIMALS AND GAME IN SWITZERLAND WITH A DIGESTION METHOD AND A SEROLOGICAL APPROACH (E S-ELISA)/

For many decades trichinellosis has not been reported among Swiss dome stic pigs. Considering the fact that Trichinella occurs in a sylvatic cycle in Switzerland, a study was designed to reevaluate the present e pidemiologic situation by investigating 10,904 fattener pigs, 218 pigs with free access to pasturage or being kept on an alp, 104 domestic b oars, 106 horses, 44 wild boars and 538 foxes using a direct and an in direct diagnostic technique (digestion method and serology with ELISA and an excretory/secretory antigen, respectively). The digestion metho d was performed according to EC-guidelines. Furthermore, 25,239 sera o riginating from a Swiss sow-serum bank were tested retrospectively for anti-Trichinella antibodies. Trichinella was not detectable in all do mestic pigs using the digestion method. Serologically, 3 fattener pigs (0.027%) and 9 sows (0.036%) demonstrated weak antibody reactivities against the Trichinella E/S-antigen. Based upon statistical calculatio ns for the negative-positive threshold, these antibody-reactions were considered to be within the normal range of variability of the test. A lthough statistically restricted, the results of the present study ind icate the absence of Trichinella within the Swiss pig population. Base d upon the rational applicability of the ELISA and its diagnostic sens itivity and specificity, this test appears as the most suitable method to perform large-scale screenings among slaughter pigs. Pigs with fre e access to pasturage and boars were all parasitologically and serolog ically negative for Trichinella. The digestion method showed that hors es and wild boars were all parasitologically negative, whereas 1.3% of the foxes were positive for Trichinella larvae.