Group Frey

Zoonotic parasites – providing veterinary expertise to One-health problems

Zoonotic parasites are transmissible between animals and humans. In Switzerland, most of these pathogens have their reservoir in the animal population where they negatively influence the health and wellbeing of their hosts. They also may pose a lingering threat to human health.

Transmission of these parasites often is food- or waterborne and a good understanding of what is "out there" eventually helps to protect us all.

Over the years, work on the small fox tapeworm (Echinococcus multilocularis), Trichinella spp., and Toxoplasma gondii have helped to understand their distribution, risk factors of infection, and to refine diagnostic tools.

Fasciola hepatica
newly excisted juvenile Fasciola hepatica fluke

Since 2020, another zoonotic parasite, namely Fasciola hepatica has come into the focus of our work. This liver fluke is quite prevalent in cattle in Switzerland, with some regional differences (Frey et al., 2018). It causes losses in milk production and fertility of affected cattle. Humans can infect themselves by ingesting the environmentally resistant metacercariae typically attached to leafy greens at the border of freshwater bodies.

While it is a rare zoonotic disease, the damage those flukes cause to the liver is substantial. Treatment relies on a single drug (triclabendazole) and resistance against this drug is emerging in numerous countries. We are therefore establishing an in vitro system to test field isolates for triclabendazole resistance and to screen for alternative compounds that could eventually be used to treat fascioliasis.