Brown Bears in Türkiye Carry Parasites With One Health Implications

Researchers surveying brown bears in Erzurum, Türkiye, have identified eggs of three gastrointestinal helminth species in bear feces and recovered adult worms from two dead animals, according to a study published in Acta Parasitologica. The team collected 333 fecal samples from four locations in the region and examined them microscopically, then confirmed the identity of helminth eggs using molecular methods. Post-mortem examinations of two dead bears completed the picture by revealing adult parasites inside the animals.

The microscopic and molecular screening showed that Baylisascaris transfuga was the most common parasite, detected in 23.7 percent of the fecal samples. Dicrocoelium sp. eggs appeared in 19.5 percent of samples, while Uncinaria stenocephala was found in 3 percent. The necropsies corroborated these findings at the adult stage: both dead bears carried B. transfuga, one harbored U. stenocephala, and one contained D. dendriticum. Matching egg detections in feces with adult worms in carcasses strengthens the species-level identifications reported for this population.

The study’s authors frame these results against a backdrop of changing land use, habitat fragmentation, and global climate fluctuations that they say are reshaping pathogen circulation dynamics by increasing the permeability of the interface among wildlife, domestic animals, and humans. In this context, wild mammals play a crucial role as natural reservoirs for parasites and as sources of environmental contamination. The authors conclude that bears may act as reservoirs for parasitic agents, playing an active role in the persistence of pathogens in the environment and their transmission to different hosts.

The researchers emphasize that the findings should be examined from a One Health perspective, which focuses on biological transmission networks within ecosystems rather than on infection foci alone. Under this framing, the detected parasites are relevant not only to bear health but also to the assessment of risks to public and animal health, because the reservoir role attributed to bears connects wildlife parasite circulation to broader ecological transmission networks.

Several limitations shape how these results should be interpreted. The fecal survey documented parasite eggs, which identifies infection at the group level but does not by itself quantify disease burden in individual bears or establish direct transmission events to other hosts. The post-mortem component covered only two animals, so the adult parasite findings cannot be generalized across the regional bear population. Within those boundaries, the work provides baseline prevalence data for gastrointestinal helminths in brown bears in Erzurum and demonstrates that molecular confirmation can be applied to eggs recovered from the feces of a large wild carnivore. The reported prevalences, ranging from 3 percent for U. stenocephala to 23.7 percent for B. transfuga, give wildlife and veterinary authorities a reference point for monitoring parasite circulation in the region, and the authors position their results as a starting point for One Health risk assessment rather than as evidence of an ongoing outbreak.

Subject of Research: Gastrointestinal helminth parasites detected in brown bears in Erzurum, Türkiye

Article Title: Gastrointestinal Helminths in Brown Bears in Erzurum, Türkiye: Biological Bridge, a Threat to Humans

Article References: Kirman, R., Akyuz, M., Dombay, S., Ciplak, A., Guven, E., & Avcioglu, H. (2026). Gastrointestinal Helminths in Brown Bears in Erzurum, Türkiye: Biological Bridge, a Threat to Humans. Acta Parasitologica, 71(6), Article 243. https://doi.org/10.1007/s11686-026-01403-0

Image Credits: AI Generated

DOI: 10.1007/s11686-026-01403-0

Keywords: brown bears, helminths, Baylisascaris transfuga, Dicrocoelium, Uncinaria stenocephala, Erzurum, Türkiye, One Health, wildlife parasites, parasitology, fecal survey, zoonosis