Detection and characterization of hemotropic Mycoplasmas in Iberian wolves (Canis lupus signatus) of Cantabria, Spain

Hemoplasmas (hemotropic mycoplasmas) are uncultivable wall-less bacteria able to infect mammalian erythrocytes. Hemoplasmas can cause anemia, especially in immunocompromised hosts, predisposing to secondary infections and even leading to death. Between 2017 and 2023, spleen samples of 131 wild Iberian wolves (Canis lupus signatus) of Cantabria (Spain) were screened for Mycoplasma spp. using a real-time PCR able to amplify a 360 bp fragment of the 16S rRNA gene and confirmed by direct Sanger sequencing. Additional conventional PCRs were performed to screen for coinfections by different Mycoplasma species and to discriminate between Mycoplasma haemocanis/haemofelis (Mhc/Mhf). Overall, 24/131 (18.3%) animals were PCR-positive. Biological and environmental factors potentially promoting hemoplasma infection in this species were analyzed. Two different hemoplasma species were detected: Mhc/Mhf (18/131; 13.7%) and Candidatus Mycoplasma haematoparvum (CMhp) (3/131; 2.3%), each with one nucleotide sequence type (ntST); three other sequences were not classified. No Mhc/Mhf and CMhp coinfection were observed. The 12 Mhc/Mhf suitable for ribonuclease P RNA sequencing were confirmed as Mhc. Mhc ntST was 100% identical to a Mhc sequence previously obtained in domestic dogs (Canis lupus familiaris), and in wild Iberian wolves of northwestern Spain (Asturias and Galicia) at a similar prevalence to the one found herein, suggesting a high Mhc genetic homogeneity in this wild population. CMhp ntST was 100% identical to CMhp sequences from domestic dogs. To our knowledge, this is the first description of CMhp in the Iberian wolf. The high genetic similarity observed in Mhc and CMhp sequences, as well as their high similarity with domestic dog sequences, suggest its recent introduction, a high level of intraspecific transmission within the wild wolf population, and likely, interspecific transmission between wolves and domestic dogs.