The recent recolonization of Central Europe by the European gray wolf (Canis
lupus) provides an opportunity to study the dynamics of parasite transmission
for cases when a definitive host returns after a phase of local extinction. We
investigated whether a newly established wolf population increased the
prevalence of those parasites in ungulate intermediate hosts representing wolf
prey, whether some parasite species are particularly well adapted to wolves,
and the potential basis for such adaptations. We recorded Sarcocystis species
richness in wolves and Sarcocystis prevalence in ungulates harvested in study
sites with and without permanent wolf presence in Germany using microscopy and
DNA metabarcoding. Sarcocystis prevalence in red deer (Cervus elaphus) was
significantly higher in wolf areas (79.7%) than in control areas (26.3%) but
not in roe deer (Capreolus capreolus) (97.2% vs. 90.4%) or wild boar (Sus
scrofa) (82.8% vs. 64.9%). Of 11 Sarcocystis species, Sarcocystis taeniata and
Sarcocystis grueneri occurred more often in wolves than expected from the
Sarcocystis infection patterns of ungulate prey. Both Sarcocystis species
showed a higher increase in prevalence in ungulates in wolf areas than other
Sarcocystis species, suggesting that they are particularly well adapted to
wolves, and are examples of “wolf specialists”. Sarcocystis species richness
in wolves was significantly higher in pups than in adults. “Wolf specialists”
persisted during wolf maturation. The results of this study demonstrate that
(1) predator–prey interactions influence parasite prevalence, if both predator
and prey are part of the parasite life cycle, (2) mesopredators do not
necessarily replace the apex predator in parasite transmission dynamics for
particular parasites of which the apex predator is the definitive host, even
if meso‐ and apex predators were from the same taxonomic family (here:
Canidae, e.g., red foxes Vulpes vulpes), and (3) age‐dependent immune
maturation contributes to the control of protozoan infection in wolves