USE OF THE MUSCLE DIGESTION MEmOD AND INDIRECT IMMUNOFLUORESCENCE REACTION IN THE DIAGNOSIS OF SARCOCYSTOSIS IN SHEEP

Svobodova Vlasta, M. Nevole: Use o/the Muscle Digestion Method and Indirect Immunofluorescence Reaction in the Diagnosis 0/ Sarcocystom in Sheep. Acta vet. Bmo, 59,1990: 157-170. A total of 1 014 sheep (522 ewes, 150 rams and 342 lambs) from the catchment-areas of the abattoirs of TiSnov, Klatovy, Strakonice and Nymburk were subjected to direct and indirect examination for sarcocystosis between October 1985 and June 1988. Direct examination with the muscle digestion method revealed muscle cysts in 75.10 %,64.67 % and 35.67 % of the ewes, rams and lambs, respectively. The ratio of macrocysts to microcysts was 22 : 608. Macrocysts were found only in adult sheep (in 3.27 % of the ewes and rams) and, except one case where they were detected in both the the oesophagus and the diaphragm, were located exclusively in the oesophagus. Microcysts were located predominantly in the diaphragm and the intensity of their occurrence increased significantly (P < 0.005) with the age of the animals. Serological examination of the blood using the indirect immunofluorescence reaction (IFR) detected specific antibodies in 88.70 %, 91.22 % and 94.44 % of the ewes, rams and lambs, respectively. In adult sheep the results of the two methods of examination coincided in 71.87 % ofthe animals, whereas a high dynamic discrepancy was found in 61.69 % of the lambs. A highly significant (P < 0.005) correlation was found between the direct demonstration of muscle cysts and the specific antibody titre of 40 and higher as recorded for the IFR. Microcysts, macrocysts, antibody, age-dependence Sarcocystosis is a parasitic disease affecting sheep in the intermediate-host phase of the life cycle of the causative agent. The genus Sarcocystis is classified within the group of obligately heteroxenic coccidia. Two months to 1 year after ingestion of the sporocysts muscle cysts develop (Dubey 1977) that are infective for the definitive host canines and felids. The species found most frequently in our country are those producing microcysts Sarcocystis arieticanis and Sarcocystis ovicanis where the definitive host is the dog. Macrocysts are characteristics of Sarcocystis gigantea where the definitive host is the cat. It is a well-established fact that pathogenic species of canine sarcocysts can produce clinical disease (inappetence, anaemia, fever, abortions) mainly in lambs and pregnant ewes. Sarcocyst species having the cat as their definitive host are regarded as non-pathogenic (Dubey 1986). Economic loss is due to gross lesions of the musculature. From the epizootiological point of view ovine sarcocystosis can be regarded as a wide-spread disease. From the data reported abroad it appears that the proportions of positive animals ranged from 6.7 % to 100 %, depending mainly on the method of examination (Afshar et a1. 1974; Boch et a1. 1978; Diez-Banos 1978; Britt ~d Baker 1983; O'Donoghue and Ford 1986; Adamczyk and Chmielowski 1987; Arnaudov and Belchev 1987; Pomroy and Charleston 1987, a. 0.). In our country Andrdko (1982) found macrocysts in 35 % of sheep in Slovakia.