Coenurus cerebralis infection in Ethiopian highland sheep: Incidence and observations on pathogenesis and clinical signs

An investigation was carried out at Debre Berhan, Ethiopia, between 1996 an d 1997, into the epidemiology of coenurosis in Menz and Horro breeds of she ep. A total of 37 heads from clinically sick and 183 heads from apparently healthy sheep were examined post mortem for the presence of the cystic larv ae of Taenia multiceps, of which 37 and 5 heads, respectively, contained 1 to 8 coenurus cysts (diameter 0.8 to 6.5 cm). The bladder worms were locate d in the cerebral hemisphere in 96% of the cases (43% and 57% for left and right, respectively), 4% being in the cerebellum. Prediction of cyst locati ons based on the direction of circling and head deviation had a 62% success rate. A retrospective study generated from the health record book at the I LRI Debre Berhan Station in 1992-1996 (199 Horro and 174 Menz) revealed tha t the incidence of coenurosis ranged from 2.3% to 4.5%. There was no signif icant breed difference in the incidence. The age of the affected sheep rang ed from 4 to 96 months, with a mean of 19.3 months, and 72% of the cases we re within the range of 6 to 24 months. In a complementary survey on necrops ied stray dogs, 8 out of 17 were positive for Taenia spp. Both studies con rm the endemicity of coenurosis at the ILRI Debre Berhan Research Station. Appropriate strategies for the control of coenurosis are suggested.