[Parenteral administration of ivermectin: effectiveness against nematodes in wild sheep (Ovis musimon)].

During the direct handling with mouflon the ivermectin (IVM) is usually parenterally administered. The used dose is equal to dose recommended to domestic sheep (0.20 mg/kg of body weight). The qualitative and quantitative parasithological differences between domestic and wild sheep (mouflon) exist (Vyslouzil, 1985; Lochman et al., 1979; Boch and Supperer, 1992). The verification of real anthelmintic efficacy in IVM treatment of mouflon was not realized up to now. The aim of this study was to describe anthelmintic efficacy of IVM administered in different doses and to select the optimum dose. The study was realized during winter season in game herd in 23 mouflons of 10-11 months old. Before treatment larvae of Muellerius capillaries (strong infection) and eggs of Nematodirus spp. and Oesophagostomum spp. (mild infection) in common faecal samples were found. The mouflons were randomly divided in four groups control group (3 head) and 3 experimental groups (6-8 animals in group). Before experimental treatment each animal in experimental groups was weighted and marked. The doses of IVM 0.20, 0.60, and 1.00 mg/kg of body weight were used. The drug was administered subcutaneously. All mouflons were placed into enclosured area of 4 hectare. 28-60 days after treatment mouflon were hunted and detail helminthological examinations (lung macroscopical evaluation, larvoscopy of lung verminous spots, larvoscopy and ovoscopy of individual faeces, necropsy of gastrointestinal organs and quantification of nematode adults) were carried out, LPG and EPG values were determined. The study was realized as a simple blind experiment--all helminthological examinations were done without knowledge of the used therapy (control x experimental animals) or IVM dose (experimental animals). Macroscopical examinations of lungs showed symptoms of strong M. capillaries infection (numerous verminous spots) in all 23 mouflons. Larvoscopical examinations (lung tissue, individual faeces) after treatment became negative in 19 treated animals, in the rest of animals the mild larvoscopical finding was determined (Tab. I). Pretreatment common LPG values (ca 2100-2230) in control animals were confirmed, findings in verminous spots of these animals were highly positive (massive presence of live larvae, eggs, and rests of nematode adults). The qualitative findings (quantitatively were findings under the detection limit for the used method) were minimum in 4 mouflons of all treated groups. Pretreatment ovoscopical findings in control animals were confirmed, too. Necropsy examinations of gastrointestinal organs were highly positive in all control animals (mean finding of 95 adults of determined nematodes), in treated animals the findings were positive in 3 animals of different groups (up to 2 adults only). In respect to reached results, pathogenicity of found nematodes, age of experimental mouflons, and economy of treatment, a dose of 0.60 mg/kg of body weight IVM dose as a optimum for parenteral treatment of mouflon nematodoses is recommended.