Histopathological, immunohistochemical, and parasitological studies on pathogenesis of Coenurus cerebralis in sheep

Abstract Introduction This study consisted in histopathological and immunohistochemical examinations of the central nervous system of 15 sheep suspected of infection with Coenurus cerebralis . The sheep displayed compulsive circling and were submitted for necropsy in 2012–2016. Material and Methods Species identification was made on the basis of the PCR analysis and parasitological examination of the cysts. Results Coenurus cerebralis cysts were detected only in the cerebral tissue of 13 sheep and in the cerebral and cerebellar tissues of 2 animals. Out of the 33 parasite cysts, most (21.21%) were located in the right and left frontal lobes of the cerebrum. The largest cyst measured 6 × 5 cm and the smallest cyst was 2 × 2 cm in size. The highest and lowest numbers of scolices were 55 and 21, and the number of rostellar hooks ranged between 22 and 30. Histopathological examination revealed the presence of typical parasitic granulomatous inflammatory foci. Immunohistochemical staining showed that most common in the periphery of the parasite cysts were, in descending order by cell number, GFAP, CD163, CD3, and CD79α-positive cells. Conclusion The study confirms the role of cellular defence mechanisms in the pathogenesis of Coenurus cerebralis infection in sheep.