IN-VITRO ASSESSMENT OF RESISTANCE TO ALBENDAZOLE AND FENBENDAZOLE IN GASTROINTESTINAL NEMATODES

Drug resistance is a great concern worldwide and in Iran. This study was carried
out to assess drug resistance of gastrointestinal nematodes to Albendazole (Alb) and Fenbendazole (Feb)
in sheep.
Materials & Methods: A total number of 90 fresh fecal samples were directly collected from the rectum
of infected sheep with an average egg per gram of feces (EPG)≤150. A dilution of 1000 eggs per 2mL
was added to each well of control, Alb (0.1μg/ml) and Feb (0.1μg/ml) groups and incubated. To
determine drug resistance, a lethal dose of 50% (LD50) was calculated based on percentage of the hatched
eggs and first larvae stage (L1) counting.
Results: EPG was lower in Feb treated groups (43.76±1.73) than Alb treated groups (65.51±1.4) and
control group (93.96±0.76). There was a significant difference between percentage of the hatched eggs
and both treated and control groups. LC50 demonstrated resistance to Alb in treated groups; while it
uncovered suspicion to drug resistance in Feb treated groups.
Conclusion: It was concluded that there was resistance to Alb and suspected resistance to Feb in sheep
examined.