Abstract
Virus neutralizing antibodies to malignant catarrhal fever virus were demonstrated in the sera of 50 oryx (O. b. callotis). The mean antibody titer in 42 adult oryx was 101.23. Two calves which were 2 wk old had a mean titer of 101.54 but the level of circulating antibody had started to decline in 2 mo. old calves. The antibody titers continued to decline only to rise steeply in 9 mo. old calves. Despite the high prevalence of antibodies in oryx no virus was isolated from blood or nasal secretions inoculated into calf thyroid cell cultures or rabbits.