title: Demographic and environmental risk factors for infection by Theileria equi in 590 horses in Israel.
abstract: The prevalence of Theileria equi infection as well as the environmental and demographic risk factors for infection was studied in 590 healthy horses from 46 farms in Israel. The prevalence of T. equi DNA was assessed using a polymerase chain reaction for a segment of the Theileria 18S rRNA gene. The overall prevalence was 26.4% (156/590). There was a significant geographical variation in the prevalence of T. equi infection, ranging from 9.3% (25/270) in the central lowlands to 81.7% (49/60) in the Golan Heights. The prevalence of T. equi infection was found to be significantly associated with management types with more horses with access to pasture being positive. Breed was identified as a risk factor for T. equi infection in a univariate analysis with relatively high infection rates in the Quarter horse and local breeds (41.1% and 36.3% respectively), while ponies and Arabian horses had a relatively low prevalence (10% and 9.1%, respectively). However, since a correlation between geographic location and breed was found, it is difficult to draw definite conclusions regarding this risk factor. Age and gender were not found as risk factors for T. equi infection in this study. The environmental variables that were significantly associated with positivity were relative humidity and minimum land surface temperature at day which both showed negative correlation with T. equi prevalence. In conclusion, Israel was found to be enzootic for T. equi infection, as indicated by the high sub-clinical infection rate, which differed between geographical areas.
authors.affiliation: 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. steinman@agri.huji.ac.il
authors.forename: Amir
authors.initials: A
authors.lastname: Steinman
authors.forename: Tal
authors.initials: T
authors.lastname: Zimmerman
authors.forename: Eyal
authors.initials: E
authors.lastname: Klement
authors.forename: Itamar M
authors.initials: IM
authors.lastname: Lensky
authors.forename: Dalia
authors.initials: D
authors.lastname: Berlin
authors.forename: Yuval
authors.initials: Y
authors.lastname: Gottlieb
authors.forename: Gad
authors.initials: G
authors.lastname: Baneth
mesh_terms: D000375:Aging; D000818:Animals; D016054:DNA, Protozoan / Q000235:genetics; D004777:Environment; D005260:Female; D006734:Horse Diseases / Q000453:epidemiology / Q000469:parasitology*; D006736:Horses; D007557:Israel / Q000453:epidemiology; D008297:Male; D016133:Polymerase Chain Reaction / Q000662:veterinary; D015995:Prevalence; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012307:Risk Factors; D016794:Theileria / Q000145:classification / Q000302:isolation & purification*; D013801:Theileriasis / Q000453:epidemiology / Q000469:parasitology*
chemical_list: D016054:DNA, Protozoan; D012337:RNA, Ribosomal, 18S