Hobby hunting promotes disease

Every August the black-legged, Lyme-disease-transmitting ticks hatch.

The number of people contracting Lyme disease and other tick-borne diseases is rising in Europe and North America. The small black parasites also feed on the omnipresent white mice and other small mammals that carry the dreaded pathogens in and on their bodies.

But this need not be the case. A new study suggests that the disappearance of mouse-hunting predators, in particular the fox, is the cause of the rising number of tick-borne diseases.

Overview of the study

In areas where predator activity is higher, the researcher Tim R. Hofmeester found 10 to 20 per cent fewer newly hatched ticks on the rodents. The study also showed that the «nymphs» are 15 per cent more likely to be infected if they live in an area with low fox and stone marten activity.

«This is the first publication to show that predators are good for our health», says Dr Taal Levi, an ecologist at Oregon State University. The study was published in Proceedings of the Royal Society B.

«The bottom line is that we should not underestimate the role of predators in the fight against ticks», says Richard S. Ostfeld, a senior scientist at the Cary Institute of Ecosystem Studies. The Hobby hunting fails as population control.

As of 2026: the situation has worsened

The Hofmeester study is more relevant today than ever. In 2024, 686 cases of TBE were reported in Germany. For 2025, researchers at the University of Hohenheim expect a new record. In Switzerland, TBE figures reached their highest level since 2013 in January 2025. Climate change is lengthening the tick season.

Less well known, but equally relevant medically: in Germany, up to 2’000 people fall ill each year with the hantavirus, another pathogen transmitted by mice that can demonstrably be kept in check by an intact predator system.

In 2025, the media reported on rising fox tapeworm infections in Europe. In Luxembourg, the infestation rate of foxes fell from 40 to below 10 per cent after the hunting ban. Hunting destabilises territories, increases migratory movements and spreads the parasite.

More on this in the dossier: The fox in Switzerland: the most hunted predator without a lobby