moxidectin and Lung-Diseases--Parasitic

Thirty ewes, 3-10 years old, known to be naturally infected with internal parasites, were allocated to three homogeneous groups of ten ewes each based on faecal nematode egg counts. The following experimental treatments were administered on Day 0: (A) moxidectin 1% injectable solution at 0.2 mg kg-1 body weight; (B) moxidectin 0.1% oral drench solution at 0.2 mg kg-1 liveweight; (C) untreated control. Faecal samples were taken on Days -7, 0, 1, 2, 3, 7, 14, 21, 28 and 35 to obtain counts of nematode eggs. One-half of the ewes in each treatment group were slaughtered 14 days after dosing, while the remainder were slaughtered 35 days after treatment to count the numbers of nasal bots, pulmonary nematodes and gastrointestinal nematodes. Moxidectin 1% injectable solution and moxidectin 0.1% oral drench solution were highly effective against gastrointestinal nematodes and against a variable infection of Dictyocaulus filiaria. Moxidectin 1% injectable solution was effective against first stage larvae of Oestrus ovis, whereas moxidectin 0.1% oral drench was ineffective.

Topics: Abomasum; Administration, Oral; Animals; Anthelmintics; Anti-Bacterial Agents; Female; Gastrointestinal Diseases; Injections; Intestine, Large; Intestine, Small; Lung Diseases, Parasitic; Macrolides; Nematoda; Nematode Infections; Nose; Parasite Egg Count; Sheep; Sheep Diseases

Two grazing experiments were performed to study the effect of moxidectin in a 'dose and move' system on Dictyocaulus viviparus infections in calves. In the first experiment, three groups of four calves were experimentally infected with 20 larvae of D. viviparus 7 weeks before moxidectin treatment of two of these groups. A sufficient suppression of Dictyocaulus infections was observed in a 'dose and move' group, but also in a group which stayed on contaminated pasture after treatment. In contrast, high faecal larval counts and lungworm disease were observed in July-August in a non-treated pasture control group. Development of immunity against lungworm was sufficient in all three groups, on pasture. In the second experiment, four out of 26 calves, including two groups of six calves and four tracer calves, were experimentally infected with 20 larvae of D. viviparus 7 weeks before moxidectin treatment combined with a move of one of the groups. No lungworm disease was observed in this 'dose and move' group. In a pasture control group high faecal larval counts and severe clinical disease were observed in August-September and one calf had to be euthanized. Although a mean burden of 129 immature lungworms was present at the time of treatment, development of immunity appeared to be low in the 'dose and move group'. In contrast, high levels of immunity had developed in the pasture control group.

Topics: Animals; Anti-Bacterial Agents; Antibodies, Helminth; Antinematodal Agents; Cattle; Cattle Diseases; Dictyocaulus; Dictyocaulus Infections; Feces; Lung Diseases, Parasitic; Macrolides; Seasons

The efficacy of moxidectin, a new endectocide against natural nematode infections, was evaluated. Twenty-five calves were divided into two groups of eight calves each and a third group of nine calves. Moxidectin was administered s.c. to two groups (I, 0.2 mg kg-1 body weight (BW); II, 0.3 mg kg-1 BW) and the third group (III) received the vehicle (placebo) s.c. Two pre-treatment and one post-treatment faecal nematode egg count determinations were made from all calves, and they were necropsied 2 weeks after treatment for the identification and enumeration of nematode parasites. Group III calves, which received the drug-free vehicle, harboured eight species of nematodes (Ostertagia ostertagi, Trichostrongylus axei, Cooperia oncophora, Cooperia punctata, Nematodirus helvetianus, Trichuris discolor, Oesophagostomum radiatum and Dictyocaulus viviparus). The mean total worm burden for this group was 8935. There was a significant reduction in the numbers of many species of nematodes (Ostertagia, Trichostrongylus, Cooperia and Nematodirus) in both treated groups. Cooperia oncophora was reduced by 94% in Group I and by 96% in Group II, while all other nematode species were reduced by 99%. Immature stages of Ostertagia and Nematodirus were significantly reduced in the two treated groups. Two weeks after treatment, the mean faecal egg counts of both treated groups were reduced by more than 98%. There was no significant difference in mean total worm burdens or egg counts between the two treated groups.

Topics: Animals; Anti-Bacterial Agents; Antinematodal Agents; Cattle; Cattle Diseases; Feces; Female; Injections, Subcutaneous; Intestinal Diseases, Parasitic; Lung Diseases, Parasitic; Macrolides; Male; Nematode Infections; Parasite Egg Count

Two controlled studies were conducted to evaluate the persistent efficacy of moxidectin (10%) long-acting (LA) injectable formulation against Dictyocaulus viviparus, Haemonchus placei, Trichostrongylus axei and Oesophagostomum radiatum in cattle. The moxidectin LA injectable formulation was administered as a single subcutaneous injection into the proximal third of the ear at a dose rate of 0.01ml/kg BW to provide 1.0mg moxidectin/kg BW. The product had persistent efficacy of >90% against D. viviparus, H. placei and Oe. radiatum for at least 150 days post-treatment and against T. axei for at least 90 days post-treatment.

Topics: Animals; Antinematodal Agents; Cattle; Cattle Diseases; Delayed-Action Preparations; Feces; Female; Gastrointestinal Diseases; Injections, Subcutaneous; Lung Diseases, Parasitic; Macrolides; Male; Nematoda; Nematode Infections; New Jersey; Parasite Egg Count; Random Allocation; Statistics, Nonparametric

Four controlled trials were conducted to evaluate the therapeutic and persistent efficacy of a new moxidectin formulation (moxidectin 1% nonaqueous injectable) against nematode parasites in cattle. This injectable moxidectin formulation, given as a single subcutaneous injection at a dose rate of 0.02 ml/kg BW to provide 0.2 mg moxidectin/kg BW, was highly efficacious (>90-100%) against larval and/or adult stages of many species of nematodes in cattle including, Dictyocaulus viviparus, Ostertagia spp., Trichostrongylus axei, Haemonchus placei, Trichostrongylus colubriformis, Cooperia spp., Nematodirus helvetianus, Strongyloides papillosus, Oesophagostomum radiatum and Trichuris spp. This formulation had persistent efficacy of >90% against D. viviparus for at least 6 weeks post-treatment, H. placei and Oe. radiatum for 5 weeks post-treatment, and Ostertagia spp. and T. axei for 2 weeks post-treatment.

Topics: Animals; Anthelmintics; Cattle; Cattle Diseases; Female; Injections, Subcutaneous; Intestinal Diseases, Parasitic; Lung Diseases, Parasitic; Macrolides; Male; Nematoda; Nematode Infections; Random Allocation

The efficacy of a move to aftermath in July combined with moxidectin or fenbendazole treatment for the control of parasitic gastroenteritis (PGE) in calves was evaluated in three field experiments in the Netherlands. In all five treated groups high gastrointestinal nematode infections and PGE were prevented by a dose and move in July. Cooperia infections increased to moderate levels in two groups treated with moxidectin and one group treated with fenbendazole. In both other groups and also for Ostertagia in these three groups, low to extremely low infections were acquired. In the first experiment high primary infections, resulting in high faecal egg counts and a moderate increase of blood pepsinogen values occurred before the dose and move. Nevertheless, these primary infections were not high enough to result in PGE. In both other experiments primary infection levels were low and faecal egg counts increased to 100-650 eggs/g faeces at the end of the grazing season. The blood pepsinogen values of non-treated control groups demonstrated that it took more than a month after their move to aftermath before substantial reinfection occurred on the new pasture. In the first and the last experiment only, high Ostertagia and Cooperia infections developed in the control group at the end of the grazing season, though it did not result in clinical PGE. The experiments demonstrate all theoretical risks of the dose and move system: (1) PGE early in the grazing season as a result of high overwintered pasture infectivity. (2) PGE just before the move as a result of an early midsummer increase in pasture infectivity. (3) PGE around housing as a result of insufficient suppression of pasture infectivity late in the grazing season. (4) Underexposure to nematode infections due to a high suppression of nematode infections. Nevertheless, it can be concluded that under normal conditions the dose and move system remains to be a valuable and easily applicable system for the control of PGE.

Topics: Animal Husbandry; Animals; Anti-Bacterial Agents; Antinematodal Agents; Cattle; Cattle Diseases; Dairying; Dictyocaulus Infections; Enzyme-Linked Immunosorbent Assay; Feces; Female; Fenbendazole; Gastroenteritis; Intestinal Diseases, Parasitic; Lung Diseases, Parasitic; Macrolides; Netherlands; Ostertagia; Parasite Egg Count; Pepsinogens; Risk Factors; Trichostrongyloidea; Weather

The residual effect of a 0.2 mg kg-1 injectable formulation of moxidectin against lungworm and gastrointestinal nematodes in cattle was studied in a grazing experiment in the Netherlands. Five groups of four calves were grazed between May and October 1991 and one similar group was used as permanently housed control group for the evaluation of the development of immunity against lungworm by challenge infections with 5000 larvae of all six groups. The main parameter used to determine the residual effect for lungworm was faecal larval counts. Additional information was derived from pasture larval counts, enzyme-linked immunosorbent assay (ELISA), respiration frequency, coughing score and, particularly for evaluating development of immunity, worm counts. For gastrointestinal nematode infections faecal egg counts and larval differentiation of faecal cultures were the main parameters used. Pasture larval counts and an ELISA for Ostertagia and Cooperia were used as additional parameters. In three treated groups lungworm larvae (re)appeared in the faeces after 67, 95 and 119 days, respectively. This implies that a 100% residual effect did not last longer than 67-21 = 46 days. The treated group with patency starting on Day 95 was exposed to extremely high infection pressure and the ELISA indicated some host-parasite interactions from 2-4 weeks after treatment. Thus some interaction between moxidectin treatment and high infection pressure delayed the onset of patency in comparison to another treated group under much lower infection pressure. In all treated groups, including the one under high infection pressure, lungworm disease was prevented and the worm counts demonstrated development of immunity. In contrast, severe lungworm disease occurred in two control groups grazing together with the 'high infection pressure' treated group. The faecal egg counts and differentiation of larvae from faecal cultures demonstrated a 100% residual effect of at least 3 weeks and indicated a high residual effect of approximately 5 weeks against Ostertagia. Moxidectin suppressed Cooperia faecal egg counts for over 98% and the results indicated a more than 95% residual effect on faecal egg output during 2-3 weeks. The ELISA results were indicative for a delay of 2 weeks in the acquisition of gastrointestinal nematode infections following moxidectin treatment.

Topics: Animal Feed; Animals; Anthelmintics; Anti-Bacterial Agents; Cattle; Cattle Diseases; Feces; Female; Gastrointestinal Diseases; Injections, Subcutaneous; Larva; Lung; Lung Diseases, Parasitic; Macrolides; Nematode Infections; Netherlands; Parasite Egg Count; Poaceae

Three groups of eight calves, naturally infected with gastrointestinal nematodes and artificially infected with Dictyocaulus viviparus were used to evaluate the efficacy of moxidectin pour-on at dose rates of 0.35 mg/kg and 0.5 mg/kg bodyweight. With both doses the efficacy was 100 per cent against adult D viviparus, Trichostrongylus axei, Ostertagia species and Nematodirus helvetianus. It was more than 99 per cent against Ostertagia and Nematodirus species fourth stage larvae. A small number of Cooperia species were found after treatment, and for this parasite, the efficacy of moxidectin ranged from 97.6 per cent against the larval stages to 98.8 per cent against the adults. No adverse reactions to the moxidectin treatment were observed.

Topics: Abomasum; Administration, Topical; Animal Feed; Animals; Anthelmintics; Anti-Bacterial Agents; Cattle; Cattle Diseases; Dictyocaulus Infections; Feces; Intestinal Diseases, Parasitic; Intestine, Small; Lung; Lung Diseases, Parasitic; Macrolides; Male; Nematoda; Nematode Infections; Parasite Egg Count; Pepsinogens; Random Allocation