moxidectin and Hypodermyiasis

The activity of the moxidectin as an 1% w/v injectable solution on first instar Hypoderma spp. has been evaluated in sixteen naturally infested young cattle. The animals were selected on the basis of their serological status and allocated to two groups of eight animals. At the end of November, one group was treated with moxidectin at a dose rate of 0.2 mg/kg via the subcutaneous route and the non treated control calves injected with the vehicle. The serological status was assessed 1, 2, 4, 8 and 12 weeks post treatment and the presence of Hypoderma lumps determined every two weeks from February to June. A 100% efficacy of the injectable formulation was demonstrated. A progressive fall of the antibody levels was observed in the treated calves for one month following treatment, suggesting a progressive action of the test compound and a limited risk of hypersensitivity.

Topics: Animals; Anti-Bacterial Agents; Antibodies; Cattle; Cattle Diseases; Diptera; Female; Hypodermyiasis; Injections, Subcutaneous; Insecticides; Kinetics; Larva; Macrolides; Male

The field efficacy of moxidectin 0.5% pour-on formulation was assessed in heifers naturally infested with Hypoderma bovis. After their first grazing season in an infested area 34 heifers were selected on the basis of results of an ELISA test performed in January 1992. Twenty-five animals were treated with moxidectin 0.5% pour-on at a dose of 0.5 mg kg-1 bodyweight and nine heifers were left untreated. No local or general side-effects associated with the treatment were noticed. In April, seven of the nine untreated heifers were affected by warble fly, and in May all were infested; none of the treated animals harboured warble fly at any time during the trial. All the extracted larvae were identified as Hypoderma bovis. On the basis of the warble counts, efficacy was 100%. The antibody kinetics, studied on blood samples collected on Days 0 (14 January), 6, 27, 48, 90, 119 and 150, showed that in the untreated animals, the antibody titres increased until May (Day 119) and then declined sharply, whereas in the treated animals there was a drop from Day 30 onwards. The mean ELISA titres of the control and treated groups became significantly different from Day 48 onwards (P < 0.05). In conclusion, moxidectin 0.5% pour-on formulation at a dose of 0.5 mg kg-1 bodyweight can effectively treat cattle naturally infested with Hypoderma bovis first instar larvae.

Topics: Administration, Topical; Analysis of Variance; Animals; Anti-Bacterial Agents; Antibodies; Cattle; Cattle Diseases; Diptera; Enzyme-Linked Immunosorbent Assay; Hypodermyiasis; Insecticides; Macrolides

Moxidectin, a systemic insecticide, was evaluated for its efficacy against the migrating first instars of the common cattle grub, Hypoderma lineatum, and against nematode egg production in beef cattle. It was observed that all three levels (0.1, 0.2 and 0.4 mg moxidectin kg-1) were 100% effective against cattle grubs when administered as a s.c. injection. The same levels of treatment were very effective (90-100%) in reducing trichostrongyle nematode egg production. However, there was a slight indication that at least one species, Cooperia oncophora, was not completely eliminated, as it was observed that small numbers of eggs began to appear after 2 weeks post-treatment when there had been no opportunity for reinfection.

Topics: Animals; Anti-Bacterial Agents; Antinematodal Agents; Cattle; Cattle Diseases; Feces; Female; Hypodermyiasis; Injections, Subcutaneous; Insecticides; Macrolides; Male; Oviposition; Parasite Egg Count; Random Allocation; Trichostrongyloidea; Trichostrongyloidiasis