[Trichinellosis in slaughtered and wild animals in Switzerland using a digestion method and a serologic method...

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