EPERYTHROZOON OVIS INFECTION IN A COMMERCIAL FLOCK OF SHEEP

A flock of sheep consisting of 60-70 winterfed ewes was examined. Bloo d was collected from approximately 30% of the sheep four times from 19 91 to 1995. Eperythrozoon ovis (Ep. ovis) organisms were not detected in blood smears stained with Wright's stain in 1991 and 1993. In 1995, examination of blood smears stained with acridine orange revealed Ep. ovis organisms in 11 of 26 sheep, whereas examination of smears stain ed with Wright's stain revealed organisms in only one ewe with a high degree of infection. The prevalence of antibodies detected by IFAT var ied from 58-100%. The antibody titres varied from 1:20 to 1:12000. Thi s investigation indicates that Ep. ovis infection once present in a fl ock of sheep may spread easily among the sheep, and that the infection seems to persist within the flock.