Contribution to the study of anthelmintic resistance of sheep gastro-intestinal strongyles on a sheep farm in the Guelma region, north-east Algeria

The prolonged use of anthelmintics is sometimes accompanied by a gradual decline in their effectiveness, refl ecting the development of resistant parasite strains. This study was conducted in the region of Guelma (northeastern Algeria) at the end of July and throughout August 2018 to investigate the sensitivity (or resistance) of sheep gastrointestinal nematodes to three anthelmintic products used in the Algerian fi eld. The sheepfold comprises 45 ewes of the Ouled-Djellal breed. The data showed that after treatment with anthelmintics, a signifi cant decrease in gastrointestinal nematode eggs per gram of feces (EPG) was observed in all groups. Resistance and sensitivity were observed in all groups studied. In group 1 (AL-Bendazol 2.5 %: albendazole), sensitivity Faecal Egg Count Reduction (FECR > 95 %) was noted in 2 out of 15 ewes (13 %), while resistance (FECR<95 %) was observed in 13 subjects (86.67 %). In the second group (Valbazen: albendazole), the numbers of cases in sensitivity and resistance were around 5 (33 %) and 10 (67 %), respectively. Group 3 (OXFENIL^® 2.265 %) revealed 2 (13 %) cases of sensitivity to oxfendazole and 13 resistance cases (86.67 %). No signifi cant difference was noted in the obtained results (sensitivity and resistance) between the three groups.