Serological and Molecular Prevalence of in Apparently Healthy Horses in Israel.

is a tick-borne hemoparasite of equines and one of the causative agents of equine piroplasmosis, which poses a great concern for the equine industry regarding animal welfare and international horse movement. The parasite is endemic in Israel; however, its seroprevalence in the area was never evaluated due to antigenic heterogenicity in the gene used in the commercially available kit. Blood samples were collected from 257 horses at 19 farms throughout the country and screened for the presence of anti- antibodies via an indirect immunofluorescent antibody test (IFAT) and for the presence of parasite DNA by nested PCR. The seroprevalence of was 69.6% and its molecular prevalence was 9.7%. The geographical area, horse's sex, breed, housing, exposure to ticks, and specifically to , and co-infection with were found to be significantly associated with serologic exposure in univariable analysis, while the geographical area and horses' sex remained significant in the multivariable analysis. The results of this study demonstrate a high level of exposure to and identify important risk factors for infection. The difference between the serological and molecular prevalence, probably related to parasite clearance, is also highlighted.