A myopathy of sheep associated with sarcocystis infection and monensin administration
Jeffrey, M.; Low, J.C.; Uggla, A.
Veterinary Record 124(16): 422-426
1989
ISSN/ISBN: 0042-4900 PMID: 2501929 Document Number: 330931
An outbreak of muscle disease affected approximately 20 of 600 ewes in spring 1987 in south-east Scotland. The clinical signs were a flaccid paralysis of the hind limbs and, in severe cases, collapse. Serum creatine kinase and aspartate aminotransferase activities were increased. Clinically affected sheep had a mean reciprocal serum antibody titre in a sarcocystis immunofluorescence antibody test of 557, whereas 22 sheep from the same flock, sampled one year earlier, showed a mean reciprocal titre of only 51. Histologically a heavy infestation of sarcocysts, myodegeneration and a non-suppurative myositis centred on degenerating sarcocysts were observed in a wide range of skeletal muscles and myocardium from four affected sheep. Monensin sodium had been inadvertently included in the protein pellet used in the feed for one week before the onset of the disease. A possible association between sarcocystis infection and monensin administration is suggested in the pathogenesis of this outbreak of muscle disease.