High prevalence in wild, free-ranging Eurasian lynx () in Finland, 1999-2015.

In Finland, free-ranging Eurasian lynx () population has grown from 30 to 40 individuals to 2800 individuals since the species became partly protected in 1962. Changes in host population size are known to have an impact on host-parasite dynamics, and the Eurasian lynx population in Finland provides a unique opportunity for studying the potential effects of dramatic population increase and expansion of a solitary apex predator on their parasite prevalence and abundance. is a zoonotic gastrointestinal parasite infecting domestic cats and wild felids worldwide. We studied infection prevalence and worm burden in 2756 Eurasian lynx individuals from Finland, covering the years 1999-2015. worms that had been collected from intestinal contents were identified based on morphology. We performed regression analyses to investigate possible associations of age, sex, and host population density with infection. We found from 2324 (84.3%, 95% confidence interval 82.9-86.0) of the examined lynx. Each year, the infection prevalence was higher than 75% and not density dependent. The parasites were strongly aggregated, with older individuals harboring fewer than younger ones did. Old females aged 9-15 years had higher abundance than males of the same age group. Our results indicate that was a common and abundant parasite of Eurasian lynx throughout the study period, regardless of the changing population size and density.