Trop. Anita. Hlth Prod. (1993) 25, 225-228 DIAGNOSIS OF STILESIA HEPATICA INFECTION IN SHEEP J. M. NGXNYI, J. A. ONYANGO-ABuJE and L. J. S. HARRISON 1 National Veterinary Research Centre, Muguga, Kenya Agricultural Research Institute, PO Box 32, Kikuyu, Kenya: i Centrefor Tropical Veterinary Medicine, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, Scotland. SUMMARY A technique for examining faecal samples for Stilesia hepatica proglottids was assessed for diagnosis of this infection in live sheep. It detected infection in 67% of all the sheep that were confirmed infected by examining the livers during meat inspection and in 63% of sheep from a farm with a history of up to 100% infection rate at slaughter. It is 100% specific since it relied on the morphological identifi- cation of S. hepatica proglottids, which are characteristic. In addition it detected Avitellina centripunctata proglottids. INTRODUCTION Stilesia hepatica, a tapeworm found in the bile ducts of sheep, goats, cattle and antelopes, occurs widely in Africa (Soulsby, 1982; Urquhart et al., 1987). Infor- mation from abattoirs indicates that S. hepatica infection is widespread in Kenya, especially among small ruminants. In Kenya's abattoirs reported prevalences ranged from 10 to 17% (Cheruiyot, 1980). However, prevalences of up to 100% have been recorded (Sachs et al., 1969) in some areas. In a more recent survey of abattoir records, it was found that S. hepatica accounted for 56% and 47% of condemned livers of sheep and goats respectively (Anon, 1986). The parasite undoubtedly causes economic losses to Kenyan farmers. In 1978 for instance, it was estimated that three million Ksh were lost as a result of liver condem- nations due to S. hepatica (Cheruiyot, 1980). This figure may have risen to over fifteen million Ksh (Anon, 1986) (36.5 Ksh = 1 US $). Two factors have acted as constraints on the study of the pathogenicity and epidemiology, which have made it difficult to assess accurately the losses due to this parasite. First, the life cycle is not fully known, although it is generally considered that the intermediate cysticercoid stage occurs in oribatid mites in pasture and that the definitive hosts become infected by ingesting the infected mites (Harwood and James, 1980). Secondly, no suitable diagnostic method existed to detect infection in live sheep. In the past, attempts to identify S. hepatica eggs in faecal samples failed. However, Coetze et aL (1991) demonstrated that mature proglottids pass through the intestinal tract without being digested and could be detected in faeces. The suitability and sen- sitivity of this method for the routine diagnosis of S. hepatica infections in live sheep was thus investigated and is reported in this paper. MATERIALS AND METHODS Sheep faeces were examined for S. hepatica proglottids as described by Coetze et al. (1991). Twenty-four infected sheep of mixed breeds and ages were identified during meat inspection as having S. hepatica present in the bile ducts. Faecal samples of approximately 40 g were taken from the rectum of each of these sheep. The pellets 225