Hidden diversity and complex transmission networks of Taeniidae and Dipylidiidae tapeworms in the Western Balkans revealed by mitochondrial markers

Abstract

Abstract Background Cestodes of the families Taeniidae and Dipylidiidae constitute a neglected but epidemiologically important group of parasites, including species of veterinary and zoonotic relevance. In the Western Balkans, their molecular epidemiology, host range, and transmission dynamics remain largely unresolved, limiting accurate assessment of their ecological and public health significance. Methods We conducted a large-scale molecular survey of cestodes collected from a broad spectrum of definitive and intermediate hosts across Croatia and Bosnia and Herzegovina over a 10-year period (2014–2024). A total of 264 specimens were analysed using mitochondrial markers ( cox1 and nad1 ), followed by phylogenetic and haplotype analyses to resolve species identity, genetic diversity, and transmission patterns. Results We provide the first comprehensive molecular evidence of nine taeniid species and multiple dipylidiid lineages circulating in the region. Generalist carnivores, particularly red foxes and golden jackals, emerged as key hubs of parasite diversity, harbouring the highest number of taxa and linking multiple transmission cycles. Several species (e.g. Taenia hydatigena , T. krabbei , T. martis ) exhibited broad host associations, while phylogenetic analyses revealed extensive gene flow across geographic boundaries, indicating a continuous regional transmission system. Notably, we detected previously unrecognised genetic divergence within Taenia pisiformis and Joyeuxiella spp., suggesting cryptic diversity. Additionally, both canine and feline genotypes of Dipylidium caninum were identified, including evidence of cross-host transmission. The detection of zoonotic species such as T. crassiceps and T. martis further highlights the relevance of these parasite communities at the human–animal interface. Conclusions Our findings redefine the epidemiological landscape of cestodes in the Western Balkans, demonstrating that parasite transmission operates within highly interconnected, cross-border networks driven by generalist carnivores and shared ecological niches. This study establishes a critical molecular baseline and provides strong evidence that southeastern Europe represents an active hotspot of cestode diversity and transmission. Integrating wildlife into surveillance frameworks is essential for accurate risk assessment within a One Health context.