Asian Journal of Current Research

The emergence of anthelmintic resistance (AR) in gastrointestinal nematodes, particularly Haemonchus contortus, represents a serious threat to small ruminant production. This study reports a field case of suspected AR in goats following treatment with fenbendazole. Pre-treatment faecal examination revealed a high parasitic burden, with a mean faecal egg count (FEC) of 1820± 52.54 eggs per gram (EPG). Larval culture confirmed Haemonchus spp. as the predominant parasite.Post-treatment evaluation at 10–14 days showed a marked reduction in FEC to 122 ± 7.97 EPG, corresponding to a faecal egg count reduction (FECRT) of 93.33%, indicating partial drug efficacy. However, at 30 days post-treatment, FEC increased to 979 ± 32.36 EPG, suggesting rapid reinfection and/or survival of resistant parasite populations. Since the observed FECRT value falls below the accepted efficacy threshold of 95%, it is indicative of suspected resistance to fenbendazole. Statistical analysis revealed significant differences in FEC across sampling periods (Kruskal–Wallis χ² = 25.812, df = 2, p < 0.001), with post hoc comparisons confirming significant variation between pre- and post-treatment counts. Despite normality indicated by Shapiro–Wilk test, FEC data were treated as non-parametric due to their over dispersed and skewed biological nature.In conclusion, the suboptimal FECRT (93.33%) combined with rapid resurgence of egg counts strongly suggests the presence of fenbendazole-resistant Haemonchus populations. These findings highlight the urgent need for routine resistance monitoring using FECRT and the adoption of integrated parasite management strategies to slow the progression of anthelmintic resistance in goat herds The emergence of anthelmintic resistance (AR) in gastrointestinal nematodes, particularly Haemonchus contortus, poses a significant threat to small ruminant production. This study documents a field case of suspected AR in goats following treatment with fenbendazole. Faecal samples were examined pre- and post-treatment using standard parasitological techniques. Initial post-treatment evaluation (10–14 days) showed absence of eggs; however, subsequent examination after one month revealed reappearance of Haemonchus eggs. These findings suggest either rapid reinfection or survival of resistant parasite populations. The study emphasizes the importance of faecal egg count reduction testing (FECRT) and integrated parasite management strategies to mitigate resistance development.