Detection of cryptic Taenia species from domestic and sylvatic transmission cycles in southern pudu deer (Pudu puda), Chile.

Anthropogenic landscape fragmentation promotes interactions between domestic animals and wildlife, facilitating cross-species parasite transmission. Through molecular identification, we report cryptic infection by three Taenia species (T. hydatigena, T. krabbei, and T. omissa) in the Southern pudu (Pudu puda), a threatened cervid endemic to temperate rainforests of South America. From necropsies of twelve pudus from rural areas of Southern Chile, we recovered 44 metacestode cysts from diverse organs. Molecular and phylogenetic analyses of the cytochrome c oxidase subunit I (COX-1) gene confirmed species identity, revealed tissue-specific tropism (T. hydatigena in the abdominal cavity, T. krabbei in muscles and thoracic organs, and T. omissa in the thoracic cavity), and uncovered mixed infections in several individuals. Haplotype network analyses showed that T. hydatigena and T. krabbei shared haplotypes with hosts from both sylvatic and domestic cycles, suggesting cross-species transmission likely mediated by free-roaming dogs and foxes as definitive hosts. In contrast, T. omissa exhibited a host-structured lineages, supporting its maintenance in an endemic sylvatic cycle involving pudus and pumas (Puma concolor) as definitive hosts. These findings highlight the Southern pudu as intermediate host in both domestic and sylvatic Taenia transmission cycles, reflecting cryptic parasite transmission dynamics in the wildlife-livestock interface of fragmented temperate forests.