Anthelmintic efficacy of an oral formulation of moxidectin against gastro-intestinal strongyles in sheep flocks from Central Italy

Introduction - Gastrointestinal strongyle (GI) infections are the most important parasitoses threatening sheep production, as they may be responsible for significant economic lost. The control of these infections is still largely based on the massive use of broad-spectrum anthelmintics, which, however, favored the onset of the anthelmintic resistance. The anthelmintic resistance is a widespread problem of increasing concern in several countries, and regarding mainly BZ (fenbendazole), IMD (levamisole) and LM (ivermectin). At present, there are no reported cases of resistance to moxidectin in Italy, but severs international studies have shown the presence of strongyle populations resistent to moxidectin that represents the molecule of choice for the treatment of GI strongylosis in small ruminants.Aim - The aim of the present study was to evaluate the efficacy of an oral formulation containing moxidectin for the treatment of sheep GI strongylosis raised in central Italy, in order to acquire more information regarding its preserved efficacy at national level.Materials and methods - The study was carried out in two dairy sheep farms located in Umbria regions (A1 and A2); the farms were found positive for GI strongyles at a screening copromicroscopic investigations conducted at the time T-7. Thirty-five sheep from A1 and 37 animals from A2 were selected for the field trial and treated orally with a commercially available product containing moxidectin. The efficacy of the treatment was calculated on the basis of the faecal reduction egg count (FECR) of the time T-14 in comparison with time T-0, according with the indications provided by the W.A.A.V.P.Result and conclusions - The results obtained showed that moxidectin has an excellent and preserved efficacy against GI strongyle infections, with a FECR value of 100%. The monitoring, the effectiveness of treatment regimens through FECR test, is extremely important as it allows to recognize the anthelmintic resistance phenomenon in the phases early, when a correct management of the molecule can still maintain the efficacy value at high levels.