A Study of Ctenodactylina tunetae (Pharyngodonidae) and Hilgertia hilgerti (Oxyuridae), Intestinal Parasites of Ctenodactylus gundi in Tunisia, Using Light and Scanning Electron Microscopy

Due to limited knowledge regarding the diversity of parasitic helminths of the common gundi (Ctenodactylus gundi), we have undertaken a helminthological survey of the gundi in Southern Tunisia. A total of 125 gundis were analysed with the main objective of providing more complete descriptions of their parasitic helminths. Among them, two nematodes, namely Ctenodactylina tunetae Bernard, 1969 (Pharyngodonidae) and Hilgertia hilgerti (Seurat, 1915) (Oxyuridae), were recovered from the large intestine and caecum. Morphological and morphometric analyses of both species were carried out using light microscopy and, for the first time, scanning electron microscopy. These nematodes were found in the large intestine and caecum with prevalences of 28.80% for C. tunetae and 55.20% for H. hilgerti. Moreover, both nematodes usually coinfect gundis, with 22.40% of hosts harbouring both species simultaneously. Our morphological and morphometric results are compared with those of previous studies. One of the most interesting results concerns the sexual dimorphism at a buccal level observed in C. tunetae, related to cephalic papillae (rounded in males; rectangular in females), lip lobes (bilobed in males; trilobed in females), and oesophageal teeth (semiarc-shaped in males; double semiarc-shaped in females). In conclusion, this study provides further knowledge of these two nematodes, as well as novel data regarding the sexual dimorphism present at the oral level.