Faecal DNA detection and molecular identification of nematodes of veterinary relevance in invasive raccoons and raccoon dogs in Central Europe.

Invasive carnivores such as the raccoon (Procyon lotor) and raccoon dog (Nyctereutes procyonoides) are widespread in Europe and may contribute to the circulation of nematodes of veterinary and zoonotic relevance at the wildlife-domestic animal interface. Molecular data on nematode taxa infecting these hosts in Central Europe remain scarce, particularly those derived from faecal DNA. We analysed 212 post-mortem faecal samples collected in western Poland (97 raccoons, 115 raccoon dogs) using PCR-based screening followed by mitochondrial cytochrome c oxidase subunit 1 (cox1) sequencing for molecular identification and phylogenetic analysis. Nematode DNA was detected in 46/212 samples (21.7%), representing minimum detection frequencies rather than true prevalence. In raccoon dogs, sequences of Uncinaria stenocephala, Toxocara canis and Crenosoma spp. were identified, with Molineus sp. representing the most frequently detected taxon. In raccoons, cox1 sequences indicated Strongyloides sp., T. canis and Molineus sp., together with several lineages that could not be reliably assigned due to limited representation of wildlife-associated nematodes in public databases. DNA of Baylisascaris procyonis was not detected. Mitochondrial cox1 sequences obtained from morphologically identified adult Molineus specimens were identical to those recovered from faecal samples, providing the first reference sequences for this genus. Overall, this study provides baseline molecular data on nematode taxa circulating in invasive carnivores in Central Europe and demonstrates the utility of faecal DNA for qualitative surveillance of nematodes of veterinary relevance.