Sarcocystiosis with neurological signs in a breeding-sheep stock

The authors observed in the past five years in a Suffolk-breed stock of an average number of 210 a disease of slow course, Lading to death within 3-8 weeks and. causing a death rate of 6.5-10.8% among the 2-13 year-old ewes a nd stud rams. The disease was characterised by pruritus of the head, trunk and limbs, loss of fleece in patches, severe emaciation, incoordinated shak ing movement (weakness of the hind part of the body) and progressive weaken ing (Figure 1 and 2). The affected sheep were either serologically positive or negative to maedi/visna virus. The treatment of the diseased animals fo r some days with potentiated sulphonamide (sulphametoxasole and trimetoprim ) Injection in a dose of 5 ml/10 body weight kg or with toltrazuril in a do se of 15 mg/body weight kg was ineffective. In the 6 carcasses examined in the laboratory severe sarcocystis infection of the skeletal muscle and the myocardium was diagnosed (Figure 3). The sch izonts (meronts) of the sarcocysts were observed in the bundles of His, the Purkinje fibres conducting the impulse in the heart (Figure 4). In the dif ferent parts of the cerebrum mild focal non-purulent inflammation - lympho- histiocytic infiltrations of the vessel walls and focal dia cell proliferat ion and in the meninx circumscribed mononuclear infiltration, and in the ce rebellum oedema and secondary destruction of the neural cells was found (Fi gure 5 and 6), Besides, in the spleen lymphoid hyperplasia, in the liver an d kidneys proliferative fetal lymphohistiocytic infiltration, in the skin f ocal mononuclear and eosinophil granulocytic infiltrations and ulcerative-n ecrotic areas were observed. The mature cysts found in the skeletal muscle contained bradyzoits in a great number (Figure 7). The ultrastructure of th e merozoites showed the picture characteristic to sarcocysts (Figure 8). Th e structure of the mature cysts with thin wall reminded of Sarcocystis arie ticanis, Previously there was no data on the occurrence of this sarcocystis species in Hungary. The authors wish to clear up with further examinations the possible intercurrent infection by S. tenella of the sheep stock. By reason of the clinical signs and the slow course the above-mentioned sar cocystiosis is remarkable because of differentiating from scrapie and visna .