INVESTIGADORES
ALVAREZ Luis Ignacio
congresos y reuniones científicas
Título:
Combined administration of ivermectin and fenbendazole against highly resistant Haemonchus contortus: assessment of dose increment
Autor/es:
LUQUE S.1, LLOBERAS M.2, ENTROCASSO C.2, LANUSSE C.1, VIRKEL, G.1, ALVAREZ L.1, LIFSCHITZ A.1
Lugar:
Liverpool
Reunión:
Congreso; Congreso Mundial de la World Association of Veterinary Parasitology; 2015
Resumen:
The combination of nematodicidal compounds from different chemical groups has been proposed as a strategy to delay the development of resistance.Previous studies involving ivermectin (IVM) and albendazole demonstrated that the enhanced systemic exposure achieved after their administration at high doses correlated to a significant increment in drug efficacy against resistant Haemonchus contortus. The aims of the current trial were: a) to characterise the plasma pharmacokinetic (PK) behaviour of IVM and fenbendazole (FBZ) administered either alone or co-administered to lambs (therapeutic dose x5) and, b) to compare the clinical efficacy of IVM and FBZ given separately (therapeutic dose x5) or co-administered to lambs naturally infected with gastrointestinal nematodes resistant to both molecules. Forty (40) lambs naturally infected with resistant nematodes were allocated into four groups (n=10) and orally treated either with IVM (1 mg/kg), FBZ (25 mg/kg) or with a combined formulation of IVM+FBZ (at the same x5 dose rate). An untreated control group (n=10) was included to assess the comparative clinical anthelmintic efficacy (14 days post-treatment) of the different treatments by the faecal egg count reduction test (FECRT). Additionally, faecal samples were cultured to determine nematode genus/species. The Kruskal-Wallis test was applied for the statistical comparison (P0.05) were observed on faecal egg counts among treated animals. The faecal cultures showed H. contortus as the main nematode specie surviving all treatments. The combined administration of IVM+FBZ at 5 times the therapeutic dose did not improve the clinical efficacy against a highly resistant H. contortus strain.