Trichinella (Trichinella spp. ) belong to the nematodes and their larvae can be in the muscles of wild and domestic pigs, horses, badgers and bears, and infect humans by eating raw and insufficiently heated meat. Infection can be fatal to humans. Therefore, animals intended for human consumption are routinely tested for trichinella (IMPLEMENTING REGULATION (EU) 2015/1375).

In Europe, the presence of four different Trichinella species has been confirmed. In Austria, there is evidence of Trichinella spiralis in foxes, Trichinella pseudospiralis in wild boar (GLAWISCHNIG et al., 2016) and Trichinella britovi in wild boar, badgers and foxes.

Red foxes are considered an important reservoir for Trichinella britovi (GOTTSTEIN et al., 2009). Entry of trichinella via fox carcasses into the human food chain via wild boar poses a potential risk in fox and wild boar overlap areas. The continuous spread of wild boar and the increase of the fox population increase the number of these risk areas (DUSCHER et al., 2005; MASSEI et la., 2015; STATISTIK AUSTRIA 2019).

A study of foxes is therefore a measure to survey abundance and geographic distribution of this parasite in the silvicultural cycle.

In this described study, 1379 foxes (sampled in 2013-2018) from the provinces of Salzburg, Tyrol and Vorarlberg were examined for trichinella. For analysis, the digestion method was used on 10 g of forelimb muscle each (IMPLEMENTATION REGULATION (EU) 2015/1375). A total of 3% of foxes (95% confidence interval CI: 2.2-4.1%) were found to have trichinella (Trichinella britovi) in the muscle. Older foxes were 2.7x more frequently infested than young animals. Foxes from Vorarlberg were with 6.8% (95% CI: 4.6-9.6%) more frequently carriers of trichinella larvae than foxes from Salzburg (1.1% [95% CI: 0.3-2.4%]) or Tyrol (1.7% [95% CI: 0.7-3.3%]). This prevalence, which is nevertheless high for Vorarlberg, is striking, especially in view of previous investigations in earlier years, which provided 3% (SCHÖPF, 1996) or 1.3% (KROIS et al., 2005). However, other investigation techniques were used here. Nevertheless, prevalences in neighboring countries are also not so high, with 1.6% and 1% for Switzerland and Bavaria, respectively (FREY et al., 2009; NÖCKLER 2005). Vorarlberg has the highest prevalence currently known in Austria.

As a precautionary measure, the disease-proof disposal of fox cores should be considered. Thus, the infection chain fox-fox but also fox-wild boar could be interrupted.

It is also essential to carry out a complete and consistent trichinella examination of wild animals intended for human consumption, which can also be carriers of trichinella.

Bibliography

DUSCHER, G., WINKELMAYER, R., PROSL, H. (2005): Distribution of wild boar in areas with trichinella findings in foxes in Austria. Wien Tierarztl Monat - Vet Med Austria 92, 315-321.

GLAWISCHNIG, W., WUNSCH, A., FÖTSCHL, H., VANEK, E. (2016). First detection of Trichinella pseudospiralis in wild boar in Austria. Wien Tierarztl Monat - Vet Med Austria 103, 183-187.

FREY, C.F., SCHUPPERS, M.E., MÜLLER, N., RYSER-DEGIORGIS, M.P., GOTTSTEIN, B. (2009): Assessment of the prevalence of Trichinella spp. in red foxes and Eurasian lynxes from Switzerland. Vet Parasitol 159, 295-299.

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KROIS, E., NÖCKLER, L., DUSCHER, G., JOACHIM, A., KAPEL, C.M.O., PROSL, H. (2005): Trichinella britovi in red fox (Vulpes vulpes) in Austria. Wien Tierarztl Monat - Vet Med Austria 92, 308-314.

MASSEI, G., KINDBERG, J., LICOPPE, A., GACIC, D., SPREM, N., KAMLER, J., BAUBET, E., HOHMANN, U., MONACO, A., OZOLINS, J., CELLINA, S., PODGORSKI, T., FONSECA, C., MARKOV, N., POKORNY, B., ROSELL, C., NAHLIK, A. (2015): Wild boar populations up, numbers of hunters down? A review of trends and implications for Europe. Pest Manag Sci 71, 492-500.

NÖCKLER, K. (2005): Occurrence and importance of Trichinella spp. in Germany. Wien Tierarztl Monat - Vet Med Austria 92, 301-307.

SCHÖPF, B. (1996): On the occurrence of Trichinella spiralis in the red fox (Vulpes vulpes) in Salzburg, Tyrol and Vorarlberg. Dissertation, University of Veterinary Medicine, Vienna. STATISTIK AUSTRIA (2019): https://www.statistik.at/services/tools/services/publikationen/detail/961; last access: 19.09.2022.  LEGAL STANDARDS COMMISSION IMPLEMENTING REGULATION (EU) 2015/1375 of 10 August 2015 laying down specific rules on official controls for Trichinella in meat. Official Journal of the European Union, L212/7-34.

Original paper GLAWISCHNIG, W., SUN, H., SCHLEICHER C., SCHÖPF, K., Wiener Tierärztliche Monatsschrift - Vet Med Austria 106, 242-248. https://www.wtm.at/Current-Issue.php