Fatal babesiosis in a free-ranging iberian wolf co-infected with and : Epidemiological implications for the cantabrian wolf population.

Health surveillance of large carnivores, such as the Iberian wolf (), allows the early detection of emerging and established pathogens in natural environments, due to their position in the top of the food chain. In 2022, the carcass of a wild wolf was found in Cantabria, Northwest Spain. A complete post-mortem investigation, including full necropsy, histopathological and molecular analysis concluded that the cause of death was a systemic hemolytic disease caused by . Furthermore, the wolf was co-infected with and . Consequently, a molecular investigation of spp., spp., spp., spp., spp., and spp. was performed in the Cantabrian wolf population (n = 91). The prevalences found were 6.3 % (5/79) for , 96.3 % (78/81) for , and 23.8 % (21/88) for . None of the wolves were positive to spp., spp., or spp. The co-infection prevalences were also investigated. To our knowledge, this is the first description of a fatal babesiosis in a wild wolf, as well as the first detection of and infection in the Iberian wolf population. We have found a low prevalence, while the prevalence is the highest recorded so far. The detection of highlights the circulation of this zoonotic pathogen in a non-endemic region.