Abstract
Coenurosis is a significant zoonotic parasitic disease caused by Coenurus cerebralis, the larval stage of the cestode Taenia multiceps. The parasite invades the central nervous system (CNS) of intermediate hosts, particularly sheep and goats, leading to neurological disorders, severe economic losses, and death in advanced cases. This study aimed to determine the prevalence of C. cerebralis infection in sheep in Egyp between March 2024 and August 2024 and to characterize its histopathological, immunohistochemical, and molecular features, with a focus on cytokine gene expression in cerebrospinal fluid (CSF). A total of 200 sheep presenting with neurological signs were examined, of which 10% were confirmed to be infected. Post-mortem examination, parasitological identification, histopathology, and immunohistochemistry targeting cluster of differentiation 3 (CD3) and tumor necrosis factor-α (TNF-α) were performed. Molecular confirmation was achieved by PCR amplification of the mitochondrial cox1 gene. Additionally, quantitative PCR was used to assess the expression of cytokine genes (IL-4, IL-6, IL-10, and IL-12) in CSF samples compared with healthy controls. Cystic lesions containing multiple scolices were mainly detected in the cerebrum and cerebellum. Histopathological examination revealed granulomatous encephalitis and perivascular cuffing. Immunohistochemical analysis showed strong CD3⁺ T-cell infiltration and TNF-α expression surrounding cyst margins. Molecular sequencing demonstrated 100% identity with reference C. cerebralis strains (GenBank: LC271726, LC271732, LC271737). Notably, IL-6, IL-10, and IL-12 were significantly upregulated (p < 0.001) in infected sheep, indicating a mixed pro-inflammatory and regulatory immune response. These findings provide valuable insights into host-parasite interactions in ovine coenurosis and support the use of integrated molecular and immunological approaches for improved diagnosis and disease management.