Molecular analysis of blood-associated pathogens in common ravens (Corvus corax) from Germany

Common ravens (Corvus corax) are intelligent scavengers that adapt to diverse environments, playing a key ecological role, but their health and ecosystem contributions can be affected by parasites. This study investigates the prevalence and diversity of blood parasite infections in common ravens using molecular techniques. Blood samples (n = 42) were collected from dead common ravens in Germany and screened for filarioid nematodes, trypanosomatids, and haemosporidian parasites. The results showed that 26.2% of the common ravens were PCR-positive for at least one parasite, with some cases of mixed infections. Filarioid nematodes were found in 16.7%, trypanosomatids in 4.8%, and haemosporidian parasites in 16.7% of the common ravens. Sequencing revealed the presence of four Leucocytozoon CytB lineages and one Haemoproteus lineage. The findings suggest that common ravens in Germany are often infected with diverse avian blood parasites, with a higher prevalence of filarioid nematodes. Further research is needed to confirm the circulation of these parasites in the common raven population and to identify the specific filarioid nematode species present in Germany.