Abstract Taenia hydatigena and Echinococcus canadensis G8 are taeniid cestodes maintained in transmission cycles involving carnivores and ungulates. This study reports a rare massive co-infection of both species in a free-ranging moose from northeastern Poland. A dissection of a four-year-old male moose, found in severe malnutrition in the area of Biebrza valley, northeastern Poland, revealed massive infection with Taeniidae larvae. Parasites were isolated and subjected to molecular identification. DNA was extracted, and fragments of the mitochondrial genes cytochrome c oxidase subunit 1 ( cox1 ) and NADH dehydrogenase subunit 1 ( nad1 ) were amplified by PCR, sequenced, and compared with reference sequences in the GenBank database. Molecular examination allowed identification of T. hydatigena and E. canadensis G8 metacestodes. Numerous T. hydatigena cysticerci were located in the omentum, mesentery, liver, and pleura, and hydatid cysts of E. canadensis G8 were found in the lungs and liver. Phylogenetic analysis showed identity with isolates from wild and domestic animals in Europe, Asia, and North America. The extensive parasite burden likely contributed to the animal’s poor condition and death. This study reveals a potential role of moose in the epidemiology of Taeniidae in Poland, indicating the environmental contamination by taeniid eggs and the need for assessing the transmission risk at the wildlife–domestic animal interface.
FILIP-HUTSCH et al. (2026) studied this question.