Persistent vector-borne infections in free-ranging red deer (Cervus elaphus) during the winter season in Norway

Red deer (Cervus elaphus) are maintenance hosts for different species of vector-borne pathogens. However, there are not many studies reporting the presence of pathogens and their co-infections in live red deer populations during winter season. Therefore, the aim of this study was to investigate the presence and prevalence of vector-borne infections in red deer during winter to determine the persistence of these infections. Blood samples were analysed from 38 free-ranging adult red deer that had been chemically immobilised during winter season in Norway. Thirty animals (78.9%) were infected with Anaplasma phagocytophilum, Babesia spp., or Bartonella spp. Seven animals were co-infected with two pathogens, and four animals had triple infections. Sequence analysis revealed the presence of A. phagocytophilum, Babesia divergens, Babesia odocoilei, Babesia bovis, and Bartonella schoenbuchensis. This study shows that free-ranging red deer can be considered as a potential host for zoonotic and nonzoonotic pathogens in Norway.