Patterns of intestinal parasite prevalence in brown bears (Ursus arctos) revealed by a 3-year survey on the Shiretoko peninsula, Hokkaido, Japan

A three-year survey on the Shiretoko Peninsula, Hokkaido, Japan, revealed that intestinal parasite prevalence in brown bears (Ursus arctos) is influenced by seasonal and host factors. Key findings include higher detection rates of Dibothriocephalus nihonkaiensis in autumn, while Baylisascaris transfuga and Uncinaria sp. showed seasonal variations linked to bear age class and dietary changes. Egg shedding for these parasites often ceased before or during hibernation, suggesting complex interactions between environmental conditions and host biology. The study analyzed 334 fecal samples using centrifugal flotation techniques and fecal DNA analysis, providing insights into parasite dynamics in wild brown bears.

Moriyoshi, M., Hayashi, N., Nonaka, N., Nakao, R., Yamanaka, M., Tsubota, T., & Shimozuru, M. (2025). Patterns of intestinal parasite prevalence in brown bears (Ursus arctos) revealed by a 3-year survey on the Shiretoko peninsula, Hokkaido, Japan. International Journal for Parasitology: Parasites and Wildlife, 26, 101048. https://doi.org/10.1016/j.ijppaw.2025.101048