Efficacy and persistent activity of moxidectin against natural Muellerius capillaris infection in goats and pathological consequences of muelleriosis (original) (raw)
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Parasite (Paris, France), 2010
Efficacité dE différEnts anthElminthiquEs vis-à-vis dE l'infEction naturEllE par Muellerius capillaris d'ovins dans lE nord-ouEst dE l'EspagnE. EffEts sur lEs gaz du sang Et lE ph vEinEux L'efficacité sur le terrain d'un traitement à dose unique par différents anthelminthiques vis-à-vis de l'infection naturelle par M. capillaris d'ovins en Galice (Espagne), ainsi que l'effet de cette infection sur la fonction respiratoire de ces ovins ont été évalués. Cinq groupes (n = 5) de brebis ont été utilisées dans cette étude. Les animaux ont été traités soit avec de l'ivermectine injectable (0,2 mg/kg), soit du lévamisole (7,5 mg/kg), soit de l'albendazole (5 mg/kg), et la charge parasitaire a été mesurée à 0, 7, 21, 42 et 63 jours posttraitement (j.p.t.) par la détermination du nombre de larves par gramme de fèces (l.p.g.) et par la mesure de la pO2, de la pCO2 et du pH dans le sang veineux à l'aide d'un i-Stat analyseur clinique mobile. Aucune différence statistique n'a été retrouvée pour ce qui concerne le nombre de larves présentes entre groupes traités et non traités. Des augmentations significatives de la pression partielle d'oxygène (pO 2 ) et de la saturation (SO 2 ) entre les jours 0 et 7 p.t. ont été observées chez tous les animaux traités. Au-delà de 21 j.p.t., ces valeurs sont revenues aux valeurs d'avant traitement. Nous pouvons conclure que, dans des conditions réelles en Galice, les programmes de contrôle des parasites ne sont pas efficaces contre l'infection par M. capillaris.
Treatment of small lungworm infestation in sheep by using moxidectin
Veterinary Parasitology, 2004
The use of moxidectin (MXD) in the treatment of small lungworm infestation (Cystocaulus ocreatus, Muellerius capillaris, Neostrongylus linearis and Protostronglylus rufescens) in sheep, was evaluated. Twenty-one sheep naturally infested with small lungworms, were divided into three groups (n = 7) and treated as follows: group A with moxidectin 1% injectable solution at a dose rate of 0.2 mg kg −1 bodyweight, group B with moxidectin 0.1% oral drench at a dose rate of 0.2 mg kg −1 bodyweight and group C being controls. Before treatment, mean faecal larval counts were 30.7, 21.1 and 26.7 lpg in group A, B and C, respectively; 14 days after treatment respective counts were 0.4, 2.3 and 63.0 lpg, (percentage reduction after moxidectin administration >96.0%); 60 days after treatment respective counts were 0.0, 0.0 and 26.4 lpg, (percentage reduction after moxidectin administration 100%). It is concluded that treatment of small lungworm infestation of sheep can be effected by using moxidectin.
Veterinary Parasitology, 1998
A total of 24 male and female equines of mixed breed, 10±20 months of age and naturally infected with internal parasites was utilized in a controlled test to evaluate the efficacy of a moxidectin 2% gel formulation at the dosage of 0.4 mg moxidectin per kg of live weight and an ivermectin 1.87% commercial paste formulation at the dosage 0.2 mg ivermectin per kg applied orally. Animals were allocated into three groups of eight horses each based on pre-treatment eggs per gram (EPG) counts and treatments were randomized among the groups. One group was kept as untreated controls. One animal in the moxidectin-treated group died before the end of the trial from a cause unrelated to treatment leaving a total of seven animals in this group. Fecal egg counts were performed three times post-treatment and the number of parasites remaining in each animal was determined. Statistical analyses using geometric means were performed at the 1% level of significance. Both moxidectin and ivermectin preparations reduced initial EPG from a mean of 1600 to 0 on Days 5, 7 and at the end of the trial on Day 14. Efficacy percentages of moxidectin and ivermectin against immature and adult nematodes were as follows: Trichostrongylus axei, Parascaris equorum, Strongylus edentatus, S. vulgaris, Triodontophorus spp. and Gyalocephalus capitatus, 100% for both products; Habronema muscae 99.5 and 99.6%, respectively, Strongyloides westeri, 100 and 99.2%, respectively; Oxyuris equi, 99.6 and 100%, respectively; small strongyles, 99.7% for both products. Of the latter, the most numerous were: Cylicocyclus insigne, Cylicostephanus longibursatus and Cyathostomum catinatum. No Gasterophilus nasalis were found in horses from either treated group, while two of eight control horses had infections with this Veterinary Parasitology 80 (1998) 29±36 0304-4017/98/$ ± see front matter # 1998 Elsevier Science B.V. All rights reserved. PII: S 0 3 0 4 -4 0 1 7 ( 9 8 ) 0 0 1 8 6 -1 parasite. Moxidectin showed greater efficacy (84.9%) than ivermectin (67.8%) against Strongylus vulgaris larvae found in the mesenteric artery aneurisms, but the difference was not statistically significant. Total parasite counts for both treated groups were significantly lower (p<0.01) than in the non-treated group. No significant differences were noted between moxidectin and ivermectin. Efficacy against the 30 nematode species found in this study was very evident for both products. As expected, neither moxidectin nor ivermectin was effective in controlling the tapeworm Anoplocephala perfoliata. No adverse reactions were observed during the experimental period. #
The influence of parasitism on the pharmacokinetics of moxidectin in lambs
Parasitology Research, 2004
Most pharmacokinetic studies on anthelmintic drugs have been performed on non-parasitized animals. However, it seems likely that the parasite burden could influence the deposition of such drugs. The pharmacokinetics of moxidectin administered orally and by subcutaneous injection was compared in lambs exposed to nematode infection and in parasite naive lambs. Plasma samples were analyzed for moxidectin over 40 days post-treatment. The main pharmacokinetic parameters calculated demonstrated a significant change in drug deposition in infected lambs when compared to controls. The area under the plasma concentration—time curve was decreased 54% and 46% by infection in the subcutaneous and oral groups, respectively. There was also a major decrease in the mean residence time in parasitized lambs. In parallel, the clearance of the drug was increased by infection. Thus, parasite infection dramatically influences the disposition of moxidectin in lambs. These results may contribute to determining a therapeutic strategy adapted to heavily infested animals.
Veterinary Medicine International, 2015
This study tested the impact of moxidectin at peripartum on nematode fecal egg count (FEC) and clinical parameters on ewes in the high altitude tropical Andes of Colombia. FEC and clinical evaluations were performed on 9 occasions in 43 naturally infected ewes before and during gestation and after lambing. Moxidectin (Mox, 200 µg kg−1) was applied at late pregnancy (T1,n=15) or 48 hours after parturition (T2,n=14). 14 untreated ewes served as controls (C). Suckling lambs(n=58)remained untreated and underwent four clinical and parasitological evaluations until 8 weeks after birth. Mox efficacy equaled 99.3% (T1) and 96.9% (T2). Highest mean FEC value reflecting periparturient nematode egg rise (PPER) was recorded in C ewes at 4–6 weeks after lambing. Significant FEC reductions were found inT1(94.8%) andT2(96.7%) ewes(p<0.05). All lambs showed a significant and ewes-group independent increase in FEC before weaning(p<0.05). Clinical parameters (anemia and diarrhea) showed time- a...
Veterinary Parasitology, 2004
The chemoprophylactic efficacy of a single dose of the 10% long acting (LA) injectable formulation of moxidectin on nematode infections in calves, was evaluated. Two similar groups of 11 female, first grazing season Holstein calves were turned out in early May on separate plots of a single, naturally infected pasture. Until 56 days post-treatment (pt), the percentage reduction in faecal egg output was 100%, remaining above 90% during the entire trial, except for day 126 pt. More than 90% of the larvae in the treated group were identified as Cooperia until 140 days after treatment and more than 70% during the rest of the trial, whereas in the control group Cooperia was the most abundant species until day 84 pt and Ostertagia from 126 days pt onwards. The reduction in faecal egg output in the treated group was reflected in the mean pepsinogen levels being below the pathogenic threshold at the end of the grazing season (1.8 units of tysrosine (U tyr)) and the absence of diarrhoea during the second half of the grazing season. In the control group pepsinogen levels remained high (mean: 5.5 U tyr) and prolonged diarrhoea occurred in the second half of the grazing season. Furthermore, the weight gain for the treated group at the end of the grazing season was 41.9 kg higher than for the control group. At necropsy, the reduction in O. ostertagi worm burden in the treated group was 97.5% compared to the control group, while the reduction in C. oncophora worm burden was 57%. An additional benefit of the long acting parasitological control, was reduced pasture contamination.
Veterinary Parasitology, 2012
Cydectin(®) 2% LA Solution for Injection for Sheep (Pfizer Animal Health) is a long-acting (LA) formulation of moxidectin for the treatment and prevention of mixed infections of gastro-intestinal nematodes, respiratory nematodes and certain arthropod parasites in sheep. To evaluate the duration of persistent efficacy against nasal bots (Oestrus ovis), a natural exposure study was conducted in Spain during the summer of 2011. One hundred and twenty nasal bot-free, Rasa Aragonesa sheep were randomly allocated to eight groups of 15 animals each. On Day 0, four groups were treated at the recommended dose rate of 1 mg moxidectin/kg bodyweight. Four groups remained untreated as negative controls. All animals were held in nasal bot-proof housing except for exposure to natural challenge when one group of treated sheep and one of group of control animals were transferred to a local pasture at either 0-20, 20-40, 40-60, or 60-80 days after treatment. Following challenge, sheep were scored for clinical signs of bot infestation, necropsied and the heads sectioned for larval recovery. Nasal bot larvae were retrieved from 7 to 11 control sheep following each exposure period indicating that adult bots were active throughout the study. In the first challenge up to 20 days after treatment, when sheep were slaughtered immediately after exposure, the majority of larvae were first instar (L1) and only 3 of the 15 control sheep were infested with second instars (L2). There was 100% efficacy against L2 and 38.1% reduction in the number of live L1 in the treated sheep but mean counts were not significantly different between treatment and control groups (P ≥ 0.05). For the subsequent exposure periods 20-80 days after treatment (necropsies 7-9 days after challenge), 6-10 sheep were infested with L1 and 9-11 control sheep were infested with L2 and third instars (L3). There was negligible efficacy against L1, but treatment with moxidectin resulted in 100% control of L2 and L3. These results are consistent with the biology of nasal bots and control with a systemic agent, as the slower growing L1 have limited feeding and are therefore less susceptible to systemic parasiticides. The study demonstrated that the persistent efficacy of this long-acting injectable formulation of moxidectin protects against the development of active O. ovis infestations for at least 80 days after treatment.
HAL (Le Centre pour la Communication Scientifique Directe), 1994
― Seven dairy-goat farms, located in central, western France, were studied in order to assess the variability in susceptibility of the lungworm Muellerius capillaris first-stage larvae (L1) to 3 different anthelmintics in relation to farm origin, by means of motility tests. The motility tests were performed by mixing larval suspensions with pyrantel (PYR), thiabendazole (TBZ) or ivermectin (IVE) solutions (3 concentrations x 3 incubation durations). The same anthelmintic tests were repeated 7 and 21 d after febantel (probenzimidazole) treatment of the goats. Before the treatment of goats, the average ratio (x 100) of Li motility compared with control were very different for the 3 anthelminthics: 44, 30 and 59, respectively for TBZ, PYR and IVE. The ratios of L1 motility were the same at days 7 and 21 after the treatment of goats. The susceptibility of Li to anthelmintics varied a great deal from 1 farm to another when goats had not been previously treated, whereas L1 s from the same farms were the same after treatment of goats. The occurrence of different motilities of Li with the anthelmintic tests from 1 farm to another should be related to the existence of different populations of M capillaris. The L1 motilities were reduced after anthelmintic treatment of goats suggesting a temporary effect on populations of M capillaris females shedding L1.