TEMPORARY SUPPRESSION OF CELL-MEDIATED-IMMUNITY IN STANDARD-BRED HORSES WITH DECREASED ATHLETIC CAPACITY

Eighty Standardbred horses, originating from 5 training campuses, with decreased athletic performance in association with symptoms such as i ntermittent fever and mild pharyngitis were examined. As control anima ls, 10 horses from a stable with normally performing horses were used. Virus isolation and clinico-chemical and serological tests were perfo rmed. Lymphocyte proliferation tests were carried out to evaluate the capacity of the cell-mediated immunity. In addition, a bioassay for eq uine type I interferon, as a marker for early viral infections, was es tablished. No specific microbe could be linked to these symptoms, but there was a temporary suppression of the cell-mediated immunity, which might be explained by the serological evidence of an EHV-2 and/or rhi novirus infection.