title: Molecular characterization of the Babesia caballi rap-1 gene and epidemiological survey in horses in Israel.
abstract: Equine piroplasmosis imposes great concerns for the equine industry regarding international horse movement, and therefore requires reliable diagnostic tools. Recent studies from South Africa and Jordan, including a preliminary study in Israel, reported extremely low seroprevalence to Babesia caballi (B. caballi) (0-1%) using the acceptable rhoptry-associated protein-1 (RAP-1) cELISA. In accordance with the study from South Africa demonstrating a significant heterogeneity in the rap-1 gene sequence of South African B. caballi isolates, the objectives of this study were to phylogenetically characterize the rap-1 gene of the Israeli isolates and determine the prevalence of B. caballi in horses in Israel. Out of 273 horses tested using the RAP-1 cELISA, only one was sero-positive, while 9.3% were positive on PCR performed on the rap-1 gene. Phylogenetic analysis of the rap-1 gene grouped the Israeli isolates in a cluster together with the South African strains (99% nt identity), but in a separate cluster from the American/Caribbean strains (81-82% nt identity). These findings support the existence of heterogeneity in the RAP-1 amino-acid sequences of the Israeli and South African isolates as compared to that used in the cELISA commercial kit and raise doubts as to the ability of this assay to serve as a sole regulatory test for international horse movement. Risk factor analysis found management and age to significantly associate with prevalence of B. caballi, as higher prevalence was noted in horses held out on pasture and a negative association was recorded with age. In addition, B. caballi was not detected in horses in the steppe-arid and extreme-arid climatic regions as compared to the wetter regions. Findings of this study emphasize the need to combine several detection methods to ameliorate the control and spread of the disease.
authors: Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel.
authors: Adi
authors: A
authors: Rapoport
authors: Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel.
authors: Karin
authors: K
authors: Aharonson-Raz
authors: Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel.
authors: Dalia
authors: D
authors: Berlin
authors: Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel.
authors: Saar
authors: S
authors: Tal
authors: Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel.
authors: Yuval
authors: Y
authors: Gottlieb
authors: Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel.
authors: Eyal
authors: E
authors: Klement
authors: Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel. Electronic address: Steinman@agri.huji.ac.il.
authors: Amir
authors: A
authors: Steinman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001403:Babesia / Q000145:classification / Q000235:genetics*; D001404:Babesiosis / Q000097:blood / Q000453:epidemiology / Q000469:parasitology*; D018740:Genetic Heterogeneity; D006734:Horse Diseases / Q000097:blood / Q000453:epidemiology / Q000469:parasitology*; D006736:Horses; D007557:Israel; D008969:Molecular Sequence Data; D010802:Phylogeny; D058974:Phylogeography; D015800:Protozoan Proteins / Q000235:genetics*; D012307:Risk Factors; D016036:Seroepidemiologic Studies
chemical_list: D015800:Protozoan Proteins; C097551:rhoptry-associated protein-1, Babesia
keywords: Babesia caballi; Horses; Piroplasmosis; RAP-1; cELISA