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

Health surveillance of large carnivores, such as the Iberian wolf (Canis lupus signatus), 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 Babesia canis. Furthermore, the wolf was co-infected with Hepatozoon canis and Leishmania infantum. Consequently, a molecular investigation of Babesia spp., Hepatozoon spp., Leishmania spp., Ehrlichia spp., Anaplasma spp., and Rickettsia spp. was performed in the Cantabrian wolf population (n = 91). The prevalences found were 6.3 % (5/79) for B. canis, 96.3 % (78/81) for H. canis, and 23.8 % (21/88) for L. infantum. None of the wolves were positive to Ehrlichia spp., Anaplasma spp., or Rickettsia 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 B. canis and H. canis infection in the Iberian wolf population. We have found a low B. canis prevalence, while the H. canis prevalence is the highest recorded so far. The detection of L. infantum highlights the circulation of this zoonotic pathogen in a non-endemic region.