Seroprevalence of antibodies to Sarcocystis neurona in horses residing in Oregon

Abstract

Objective - To determine seroprevaience of antibodies to Sarcocystis neurona in neuroiogically normal horses residing in 4 regions of Oregon and to describe the effects of age, gender, breed, and housing on se roprevalence within each region. Design-Prevalence survey Sample Population -Serum samples from 334 horses systematically selected by practicing veterinarians. Procedure -Antibodies to S neurona were measured in sera, using a western blot Information including age, gender, breed, housing, geographic location, and duration of residence was obtained for each horse Data were analyzed, using descriptive statistics. Results -45% (149/334) of horses evaluated were seropositive for antibodies to S neurona with significant differences in the percentage of seropositive horses from different regions of the state Seroprevalances of antibodies to S neurona in horses in regions I and II, west of the Cascade Range, were 65 and 60%. respectively; whereas seroprevalances in central and eastern Oregon, regions III and IV, were 43 and 22%, respectively. Seroprevalence consistently increased with age of horse for each region Gender, breed, and housing were not associated with significant differences in Seroprevalence of antibodies to S neurona in the overall sample population, or in compansons of samples obtained from horses within a particular region, or among samples obtained from horses residing in different regions. Clinical Implications-The high serop'evalence of antibodies to S neurona .n nourologically normal horses indicates that analysis of serum alone would not be useful for definitive diagnosis of equine protozoal myeloencephalitis in horses in Oregon.