Document Type : Original Articles
Dakahlia Directorate of Veterinary Medicine, Ministry of Agriculture, Mansoura, Egypt
Parasitology Department, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
Parasitology Department, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt
Department of parasitology, Faculty of Veterinary Medicine , Mansoura University, Mansoura 35516, Egypt
Objective: To investigate, for the first time, the anthelmintic resistance of different trichostrongyles infecting sheep in Dakahlia governorate, Egypt.
Design: Randomized controlled study.
Animals: 820 sheep reared within 10 freely grazing herds with infrequent deworming practices.
Procedures: Fresh fecal samples were collected; their floats were examined for the trichostrongyle eggs, which were then identified employing the fecal cultures and/or ITS2-PCR amplifications. Sheep (n=500) whose samples had egg counts ≥ 150 eggs per gram (EPG) of feces were selected and divided in each herd into 5 equal groups; each group received one of the tested anthelmintics including albendazole (5 mg/kg BW), levamisole (7.5 mg/kg BW), ivermectin (0.2 mg/kg BW) and doramectin (0.2 mg/kg BW), whereas the fifth group were kept untreated. The EPGs were detected for all groups at the time of treatment and weekly for 10 times post-treatment. Fecal egg counts reduction percentage (FECR%) and egg reappearance periods (ERP) were estimated.
Results: The examined herds were mostly infected with Haemonchus contortus; however, few larvae of Trichostrongylus species were detected in fecal cultures of 2 herds. In the untreated groups, the EPGs increased gradually over the time of the experiment; however, no eggs were detected in samples of all treated groups 7 days post treatment resulting in 100% FECR. The macrocyclic lactones (ivermectin and doramectin) displayed longer ERPs than the benzimidazoles (levamisole and albendazole).
Conclusion: No anthelmintic resistance was noticed in trichostrongyles-infected sheep population from Dakahlia governorate, Egypt, and the use of ivermectin to treat the trichostrongyles-infected sheep is recommended.