Anti-parasitic activities of four synthetic chemicals anthelmintics on Haemonchus contortus

Synthetic anthelmintic (AHs) have always been used in veterinary medicine. The increasing development of resistance to these AHs in livestock parasites threatens animal health and global production, calling into question their effectiveness. In vitro egg hatch inhibition assay (EHA) and larval development test (LDT) performed showed ovicidal and larvicidal activities of four AHs compared to the control (PBS). However, a suspicion of Haemonchus contortus resistance to Bolumisole M1 (IC₅₀ = 0.122µg/mL) and Ivomec-D (IC₅₀ = 0.130µg/mL) was recorded after the EHA. Similarly, resistance was observed to Bolumisole M1 (IC₅₀ = 0.024µg/mL), Ivomec-D (IC₅₀ = 0.07µg/mL) and Kelanthic (IC₅₀ = 0.144µg / mL) following the LDT. These results show that cases of parasite resistance to AHs exist in small ruminants in Burkina Faso. Therefore, a reasoned use of AHs could be a good approach in the control of gastrointestinal nematodes of small ruminants in Burkina Faso. Subsequent in vivo studies should be conducted to confirm this resistance in the real conditions of these ruminants.