Parasitic Characterization and Histopathological Alterations in the Local Naemi Sheep, Ovis aries awassi, Naturally Infected with Dicrocoelium dendriticum in Riyadh, Saudi Arabia

Abstract

Background: The Naemi sheep, Ovis aries awassi, is an important local meat source in Saudi Arabia. The current study investigated the impact of natural infection with Dicrocoelium dendriticum flukes on local sheep. Parasitic burden, egg output and gross external and internal appearances of the liver were investigated. Methods: Fifteen naturally infected sheep were targeted in this study based on positive D. dendriticum hepatic infection and fecal egg counts, in addition to five healthy (control) ones for comparison. Adult flukes were also characterized in terms of morphometric and diagnostic morphological characters. Result: Data showed significant differences in parasite burden between low, median and highly infected sheep as well as many morphological parameters within worms. Livers were compared based on the level of injury, histological alterations and the number of D. dendriticum adult worms. Macroscopically, livers were enlarged and darkened in color, with thicker bile ducts and fibrosis. Furthermore, leucocyte infiltration, bile duct fibrosis and hyperplasia were investigated. Hepatic lesions were scored at different degrees of severity and numbers. In infected levels, a positive correlation was observed between the number of adult flukes, external macroscopic lesions, bile duct hyperplasia and fibrosis. On the other hand, a negative correlation between these symptoms and the level of leukocyte infiltration was observed.