nemadectin and Intestinal-Diseases--Parasitic

Thirteen critical tests (n = 11 horses and 2 ponies) and 4 controlled tests (n = 4 donkeys and 6 horses) were performed to evaluate the activity of the experimental macrocyclic lactone compound F28249-alpha against internal parasites of equids. In the critical tests, activity was determined mainly against the large parasites, but 1 critical test also included benzimidazole-resistant small strongyles. In the controlled tests, evaluation of drug activity included large parasites and stomach worms in all 4 tests, and lungworms in 2 tests. The period between treatment and euthanasia was 6 to 9 days for the critical tests and 14, 17, or 52 days for the controlled tests. The compound was administered by stomach tube at dose rates of 1, 2, 3, 3.5, or 4 mg/kg of body weight. In the critical tests, removal at all 5 dose rates was 100% for Gasterophilus nasalis (2nd and 3rd instars), Parascaris equorum (mature), Strongylus vulgaris, and Strongulus edentatus from the gastrointestinal tract. For Gasterophilus intestinalis in the stomach, mean removals of 2nd instars were 88% at the rate of 2 mg/kg and 93% to 100% at rates greater than or equal to 3 mg/kg. For 3rd instars, mean removals were 7% at 1 mg/kg, 77% at 2 mg/kg, 90% at 3 mg/kg, and 98% at 3.5 mg/kg. Discharge of G intestinalis in feces was typically a slow, prolonged process and probably higher removal values, especially at lower dose rates, would have attended a longer interval after treatment before necropsy examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Abdominal Muscles; Animals; Anti-Bacterial Agents; Diptera; Eye; Female; Horse Diseases; Horses; Intestinal Diseases, Parasitic; Lactones; Larva; Lung; Macrolides; Male; Parasites; Parasitic Diseases; Parasitic Diseases, Animal; Perissodactyla; Strongyloidea

Nemadectin, a new broad-spectrum endectocide, was highly efficacious against natural infections of all the major canine gastrointestinal helminths. At single oral dosages of 0.2-0.4 mg kg-1 body weight (BW), a liquid formulation administered in gelatin capsules was 100% effective in eliminating natural infections of Toxocara canis, Toxascaris leonina, Ancylostoma caninum and Uncinaria stenocephala. Tablets (267 mg) containing 4.6% nemadectin given at a rate of 1/3 tablet per 20 kg BW (0.2 mg nemadectin kg-1) were 100% active against T. canis, A. caninum and U. stenocephala. With both formulations, an increase in the dose rate to 0.6-0.8 mg kg-1 BW resulted in 99-100% elimination of Trichuris vulpis infections. No adverse reactions were observed in any of the treated dogs.

Topics: Administration, Oral; Animals; Anti-Bacterial Agents; Antinematodal Agents; Capsules; Dog Diseases; Dogs; Helminthiasis; Helminthiasis, Animal; Intestinal Diseases, Parasitic; Macrolides; Tablets

A controlled blind test was performed in 1984 to evaluate the anthelmintic activity of experimental formulations of compound F28249-alpha against gastrointestinal parasites in lambs in Kentucky. Twenty-five lambs were allotted to 5 groups of 5 lambs/group. The drug was administered SC to 2 groups (A, 0.2 mg/kg of body weight; B, 0.3 mg/kg) and orally to 2 groups (C, 0.2 mg/kg; D, 0.3 mg/kg). Group E received a placebo subcutaneously. Lambs were euthanatized 7 days after treatment for necropsy and identification and enumeration of worm parasites in the gastrointestinal tract. Group-E lambs harbored 7 genera (including 10 species) of nematodes and 1 genus of tapeworms. Worm collection data for group-A lambs indicated 97% to 100% of the mature Haemonchus, Ostertagia, Trichostrongylus, and Trichuris, and immature Haemonchus were removed; and 23% to 73% of the mature Cooperia, Nematodirus, and Strongyloides, and immature Nematodirus were removed. In group-B lambs, 94% to 100% of the mature Haemonchus, Nematodirus, Ostertagia, Trichostrongylus, and Trichuris, and immature Haemonchus were removed as were 70% to 84% of mature Strongyloides and immature Nematodirus, respectively, and 0% for mature Cooperia. The percentage of all nematodes removed in group C and D was 100%, except for Cooperia (95%) in group C and immature Nematodirus (93% and 95%), respectively. Toxicosis was not apparent. Small fibrotic or blood streaked lesions were observed at necropsy in muscle at the injection site of 2 lambs in group B and 1 lamb in group E.

Topics: Administration, Oral; Animals; Anthelmintics; Anti-Bacterial Agents; Cestode Infections; Haemonchus; Injections, Subcutaneous; Intestinal Diseases, Parasitic; Lactones; Macrolides; Nematode Infections; Ostertagia; Parasite Egg Count; Sheep; Sheep Diseases; Trichostrongylus; Trichuris