High seroprevalence of Toxoplasma gondii and Neospora caninum in the Common raven (Corvus corax) in the Northeast of Spain

In recent years, multiple cases of aggressive behavior of Common ravens (Corvus corax) have been reported by farmers in Catalonia (NE Spain), including attacking of newborn animals and consumption of dead foetuses. In the present study, seroprevalence of Toxoplasma gondii and Neospora caninum was determined from 113 legally trapped and released Common ravens. T. gondii antibodies were found in 91 (80.5%; CI 95%:72-87) of 113 sera tested by the modified agglutination test. Antibodies to N. caninum were found in 24 (35.8%; IC 95%: 24.5-48.5) of 67 Common ravens tested by an indirect fluorescence antibody test with titers ranging from 1:50 (n=18) to ≥1:100 (n=6). To the author's knowledge, this is the first report of the presence of T. gondii and N. caninum antibodies in C. corax. The seroprevalence detected is one of the highest reported worldwide in wild birds, suggesting an important role for this species in the epidemiology of both parasites.