Harbor porpoises (Phocoena) are definitive hosts for intestinal Diphyllobothrium sp. cestodes, zoonotic parasites with a heterogeneous life cycle and fishes as second intermediate hosts. Prevalence and level of infection of Diphyllobothrium cestodes in 661 dead-found harbor porpoises from the German North and Baltic Seas within a 30-year period were investigated. Molecular species identification of cestodes was carried out, using ribosomal and mitochondrial gene markers. Pathogenic impact of cestodes on intestinal tissue was analyzed by using review of histopathological records. With 18 cestode-infected harbor porpoises, prevalence was low (3 %) in both ecosystems. Infected animals were mostly young and exhibited mild infection levels. Cestode infection did not contribute significantly to cause of death and disease of the infected individuals and histopathological alterations of intestinal tissue were mostly mild. Tapeworms were molecularly identified as D. stemmacephalum. The findings validate past morphological records in the study area for the first time and confirm harbor porpoises as definitive hosts for D. stemmacephalum. D. stemmacephalum can accidentally infect humans. Future research on cetacean definitive host populations and species-specificity as well as life cycle and intermediate host species of D. stemmacephalum is crucial for a risk assessment in the sense of the One Health concept.

Amphibian populations are undergoing dramatic global declines, with infectious diseases recognized as major contributors. While chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), and disease caused by ranaviruses are well known, herpesviruses in amphibians remain comparatively neglected. We conducted a passive survey using carcasses collected between 2022 and 2025 in Schleswig-Holstein, northern Germany. Dead amphibians (n = 187) were dissected. Skin, kidney, liver, and brain samples were screened for Bd, ranaviruses, bufonid herpesvirus 1 (BfHV1), and ranid herpesvirus 3 (RaHV3) by PCR. BfHV1 was detected in nearly half of the Bufo bufo (common toads; 48.6%), while RaHV3 was identified in 23.6% of the Rana temporaria (common frogs) examined. Bd was detected in a single B. bufo, while ranaviruses were not detected. BfHV1 was present in skin, liver, kidney, and brain samples, whereas RaHV3 was detected exclusively in skin samples. No macroscopical or histological lesions characteristic of herpesviruses or Bd were found. However, the carcass-based approach frequently limited detailed examination due to compromised sample quality. Our findings confirm the presence of amphibian herpesviruses (BfHV1 and RaHV3) in the region without associated lesions, raising questions about their potential to cause systemic infections. Furthermore, our results highlight the limitations of carcass-based surveillance and underscore the need for complementary diagnostic approaches, such as immunohistochemistry and meta-omics.