emerging with high prevalence and co-infections in "fighting dogs" in Hungary.

is considered as an emerging protozoan parasite of dogs in North America and Europe. However, no data have been published on its prevalence, molecular-phylogenetic characteristics and associated co-infections in dogs used for illegal fighting (i.e. predisposed to acquiring this piroplasm biting) in Europe. In this study, blood samples from 79 American Staffordshire Terrier dogs, confiscated for illegal dog fights, were molecularly analyzed for tick-borne pathogens. was detected in 32 dogs, i.e. with a prevalence of 40.5%. In addition, was found in 8 samples (prevalence of 10.1%), for the first time in dogs in Hungary. Canine hemoplasmas were also identified in 49 samples (62%): only in 32 (40.5%) dogs, only " Mycoplasma haematoparvum" in 9 (11.4%) dogs, and both hemoplasmas in 8 (10.1%) dogs. Thus, hemoplasma infections also showed a particularly high prevalence in this dog population. Based on a partial fragment of the 18S rRNA gene, from Hungary exhibited complete sequence identity with conspecific strains reported from Europe and Asia. The cytochrome oxidase subunit 1 (1) gene sequence of this isolate showed the closest identity with reported from Japan but had a nonsynonymous mutation (M33I). Furthermore, the 11 -positive samples analyzed for sequence variants of the cytochrome () gene showed the presence of a common mutation (P310S). Most importantly, had two further nonsynonymous mutations, M121I and F258L, in a dog with severe and relapsing anemia following atovaquone treatment. Phylogenetically, both sequence variants clustered together, with a clear geographical pattern showing the closest relationship of both haplotypes identified in Hungary with those from China and Japan. To the best of our knowledge, this is the first 1 and characterization of in Europe, as well as the first report on the emergence of this piroplasm and hemoplasmas with high prevalence among "fighting dogs" north of the Mediterranean Basin.