Morphometry, molecular identification and histopathology of Passalurus ambiguus Rudolphi, 1819 in domestic rabbits (Oryctolagus cuniculus) in Qena, Upper Egypt.

In Egypt, domestic rabbits are commercially used for meat production. Adversely, gastrointestinal helminthiasis largely delays such concern. Passalurus ambiguus is a common intestinal nematode that infects rabbits causing intestinal disorders and death in severe infection. Therefore, domestic rabbits collected from several locations (poultry slaughter shops, rabbits farms, markets and public owners) in Qena, Upper Egypt. Passalurus ambiguus worms were detected in 90 out of 200 rabbits (45%). Grossly, they appeared as small white nodules in the appendix of the rabbits examined. Adult worms were described morphologically using light and scanning electron microscopy. Adult male measured 4.622 mm (2.838-7.172 mm) in length and 0.278 mm (0.139-0.558 mm) in width. Adult female measured 5.622 mm (2.347-9.532 mm) in length and 0.314 mm (0.185-0.381 mm) in width. SEM showed a transverse cuticular striations on the body of both males and females, four papillae on the dorsal and ventral surface and the mouth was triangular and surrounded by three teeth. Phylogenetic data proved the occurrence of the intestinal nematode, Passalurus ambiguus. Microscopically, heavy worms infestated the appendiceal layers causing appendicitis manifested by granuloma with hyperplasia in the epithelial lining inducedobstruction in the lumen. It could be concluded that morphological features, molecular phylogenetic data, and histopathological findings clearly identified the present species as Passalurus ambiguus Rudolphi, 1819. © Indian Society for Parasitology 2022.