moxidectin and Intestinal-Diseases--Parasitic

A study was conducted to assess the effectiveness (fecal egg count reductions) and benefit (improvement in feed efficiency, average daily gain, health, and so forth) of a macrocyclic lactone (moxidectin [Cydectin Injectable] or doramectin [Dectomax 1% Injectable]) alone or in combination with a benzimidazole (oxfendazole [Synanthic Bovine Dewormer]) as used in steers upon their arrival at a feedlot. The cattle were kept in the feedlot for 181 days. Only minor differences in fecal egg count reductions were seen among treatments, with all egg counts reduced by more than 98% by 28 days posttreatment. Likewise, no statistically significant differences among treatments were seen in terms of animal performance (feed efficiency, intake, gain, morbidity, mortality, and carcass quality). All three treatment regimens appear to be comparable in decreasing nematode burdens and the consequences thereof in feedlot cattle.

Topics: Animals; Anthelmintics; Benzimidazoles; Cattle; Cattle Diseases; Drug Administration Schedule; Drug Therapy, Combination; Feces; Intestinal Diseases, Parasitic; Ivermectin; Macrolides; Meat; Parasite Egg Count; Southwestern United States; Treatment Outcome

Use of moxidectin long-acting injectable and ivermectin injectable in female Bos taurus beef-type calves was evaluated in terms of efficacy (fecal egg counts) and performance parameters (weight gain). In this 150-day study, moxidectin-treated calves gained 20% more weight than did ivermectin-treated and control calves. Mean fecal egg count reductions ranged from 76.7 to 99.0 for moxidectin and -0.8 to 83.4 for ivermectin. Moxidectin long-acting injection provided efficacious (immediate as well as long-term) egg count suppressions as well as enhanced animal productivity (weight gains). The study also showed that Cooperia spp appear poised to present the most immediate challenges once long-acting macrocyclic lactone treatments become available.

Topics: Animals; Antiparasitic Agents; Cattle; Cattle Diseases; Feces; Female; Injections, Subcutaneous; Intestinal Diseases, Parasitic; Ivermectin; Macrolides; Nematode Infections; Parasite Egg Count; Treatment Outcome

In a trial designed to evaluate the efficacy of the recommended dosage of moxidectin 2% oral gel against the gastric stages of Gasterophilus spp., 14 ponies were selected from a herd on the basis of the inclusion criterion of the presence of Gasterophilus spp. eggs attached to their hair coats. After random allocation, the ponies were treated with 1 of 2 treatments, moxidectin 2% equine gel in a single dose at the commercial dosage of 400 microg moxidectin/kg body weight or placebo gel. The animals were necropsied 14 days posttreatment. Efficacies against second- and third-instar Gasterophilus intestinalis De Geer were 100% and 99.5%, respectively.

Topics: Administration, Oral; Analysis of Variance; Animals; Anti-Bacterial Agents; Diptera; Female; Gels; Horse Diseases; Horses; Insecticides; Intestinal Diseases, Parasitic; Larva; Macrolides; Male; Stomach

The efficacy of a 2% moxidectin equine gel at a dosage rate of 0.4 mg kg-1 was evaluated in a controlled trial at Utrecht University. Twelve yearling castrated male Shetland ponies grazed a pasture of 2 ha from May 1994 until housing in November. Six ponies were treated with moxidectin, whereas the others served as non-treated controls. Necropsy was carried out 35 days after treatment. Greater than 99% efficacy of moxidectin was observed on faecal egg output. No effect of moxidectin was observed on mucosal inhibited early cyathostome L3 (EL3) or on the total numbers of mucosal developing stages. However, a 89.6% reduction was observed on large mucosal fourth stage larvae (L4). Moxidectin treatment probably triggered resumption of development of EL3. Moxidectin appeared to be highly effective (95-100%) on lumenal L4 cyathostomes, adult strongylids, Strongylus vulgaris larvae from the arteries, S. edentatus larvae from the abdominal wall and Trichostrongylus axei. Moxidectin had relatively poor efficacy against Gasterophilus intestinalis and had no effect on Anoplocephala perfoliata. No side-effects of moxidectin treatment were observed.

Topics: Animals; Anti-Bacterial Agents; Antinematodal Agents; Intestinal Diseases, Parasitic; Intestinal Mucosa; Larva; Macrolides; Male; Netherlands; Parasite Egg Count; Strongyle Infections, Equine; Strongyloidea

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Antinematodal Agents; Equidae; Feces; Female; Horse Diseases; Horses; Intestinal Diseases, Parasitic; Ivermectin; Macrolides; Male; Parasite Egg Count; Pyrantel Pamoate; Strongylida Infections; Trichostrongylosis

A controlled trial was conducted to determine the anthelmintic efficacies of moxidectin and mebendazole. The compounds were administered orally at doses of 0.2 mg/kg bodyweight and 15.0 mg/kg bodyweight, respectively, to lambs infected experimentally with large numbers of gastrointestinal nematode larvae including a benzimidazole-resistant strain of Haemonchus contortus. Moxidectin was 100 per cent effective against adult H contortus, Ostertagia species, Trichostrongylus colubriformis, Cooperia curticei and fifth stage larvae of Oesophagostomum species and Chabertia ovina, but was only 76 per cent effective against adult Strongyloides papillosus. Mebendazole was 100 per cent effective against adult Ostertagia species and T colubriformis, but reduced the numbers of adult C curticei by only 39 per cent, S papillosus by 58 per cent, H contortus by 76 per cent, and fifth stage larvae of Oesophagostomum species by 79 per cent and C ovina by 72 per cent.

Topics: Administration, Oral; Animals; Anthelmintics; Anti-Bacterial Agents; Female; Intestinal Diseases, Parasitic; Macrolides; Mebendazole; Nematode Infections; Sheep; Sheep Diseases

Efficacies of moxidectin and ivermectin were compared in four groups of eight ponies with natural parasite infections: placebo (Control), oral moxidectin gel at 0.3 mg kg-1 of body weight (Mox 0.3), oral moxidectin gel at 0.4 mg kg-1 of body weight (Mox 0.4), and oral ivermectin paste at 0.2 mg kg-1 of body weight (Ivermectin). Fecal samples were taken 0 and 2 weeks after treatment. Animals were necropsied and worms were collected 2 weeks after treatment. Moxidectin and ivermectin showed similar efficacy (99%) against adult cyathostomes, Strongylus spp., Triodontophorus spp. and Habronema muscae. Both drugs were also more than 98% effective against luminal cyathostome and Oxyuris equi fourth stage larvae (L4). Neither drug was effective (0-10.1%) against hypobiotic early third stage cyathostome larvae (EL3). Moxidectin was moderately effective (62.6-79.1%) in removing encysted cyathostome late third stage larvae (LL3) and L4, whereas ivermectin was ineffective (0%) against these stages. By contrast, ivermectin was 95.4% effective against Gasterophilus spp. third instar stage, whereas moxidectin was only 0-20.4% effective.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Feces; Female; Horse Diseases; Horses; Intestinal Diseases, Parasitic; Ivermectin; Macrolides; Male; Parasite Egg Count; Strongyle Infections, Equine

The efficacy of moxidectin, 'injectable' and 'pour on', against gastrointestinal nematodes was determined in cattle in two separate field trials (Trial I in 1990 and Trial II in 1991) with respectively 88 and 94 young grazing cattle of either sex. The efficacy was measured on the basis of the reduction of the egg output and of the evaluation of the results from larval differentiation. Animals in Group MI received 0.2 mg kg-1 body weight (b.w.) moxidectin injectable solution in Trial I on Day 0. Group CI was not given any medication on Day 0, but 0.2 mg kg-1 b.w. ivermectin injectable solution (Ivomec) was applied after 2 weeks to prevent clinical disease. In Trial II, animals in Group MP were treated with pour on moxidectin (0.5 mg kg-1 b.w.) on Day 0. Animals in Group CP serving as controls for Group MP during the first part of the trial received the same formulation at the same dose 2 weeks after treatment of Group MP. When the egg output was compared within treated groups, the egg count reduction was very similar post treatment (p.t.) with both formulations being 96.3% and 96.6% on Day 7 after the application of injectable moxidectin or pour on moxidectin, respectively, and 90.7% and 92.5% on Day 28 p.t. When egg counts of treated and control animals were compared (corrected for the e.p.g. values before treatment) the egg count reduction was 95.4% and 91.5% on Day 7 and 92.9% and 84.8% on Day 14 p.t. with either the injectable or pour on formulation. Pour on moxidectin seemed to be more effective against Ostertagia spp. than against Cooperia spp. Animals treated with injectable moxidectin gained significantly more body weight (4.2 kg per animal) than the controls from Day -7 to Day +14, while no significant difference in weight gain was achieved within 2 weeks after treatment with pour on moxidectin.

Topics: Administration, Topical; Animals; Anthelmintics; Anti-Bacterial Agents; Cattle; Cattle Diseases; Feces; Female; Injections; Intestinal Diseases, Parasitic; Macrolides; Male; Nematode Infections; Parasite Egg Count; Weight Gain

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Benzimidazoles; Drug Resistance; Feces; Intestinal Diseases, Parasitic; Levamisole; Macrolides; Male; Nematoda; Nematode Infections; Parasite Egg Count; Sheep; Sheep Diseases

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

The activity of moxidectin was evaluated in 1988 and 1989 against natural infections of internal parasites in 20 critical tests (n = 20 equids) and three controlled tests (n = 20 equids). Two formulations, injectable administered intramuscularly (i.m.) or intraorally (i.o.) and gel i.o., were given at dose rates of 0.2, 0.3 or 0.4 mg kg-1 body weight. For the critical tests (all three dose rates evaluated), removals of second instar Gasterophilus intestinalis were 93-100%, except (89%) for the injectable formulation (i.m.) at 0.2 mg kg-1. Removals of third instar G. intestinalis were 88-100% for the injectable formulation given i.m. or i.o. and 93-100% for the gel formulation, except (53%) for one batch (0.4 mg kg-1). Activity was 100% for third instar Gasterophilus nasalis, Parascaris equorum, Strongylus vulgaris and Strongylus edentatus. For Oxyuris equi, removals were 91-100%, except (27%) for one batch of the injectable formulation given i.o. at 0.3 mg kg-1. There was apparent activity against migrating S. vulgaris and S. edentatus at various dose rates and routes of administration for both formulations. At necropsy, there were local reactions observed at the injection site of three equids. In the controlled tests, dose rates were 0.2 or 0.4 mg kg-1. Removal of third instar G. intestinalis was highest for the injectable formulation given i.m. All formulations and dose rates were highly effective against S. vulgaris and S. edentatus, but variable and incomplete against O. equi. Removal was excellent on Habronema muscae and on migrating S. vulgaris and S. edentatus, although incomplete on S. vulgaris. Gasterophilus nasalis third instars and P. equorum were present in low numbers in some non-treated equids, but none were recovered from treated equids. Toxicosis was not evident.

Topics: Administration, Oral; Animals; Anthelmintics; Anti-Bacterial Agents; Female; Gels; Horse Diseases; Horses; Injections, Intramuscular; Intestinal Diseases, Parasitic; Macrolides; Male; Parasitic Diseases; Parasitic Diseases, Animal

Anthelmintic efficacy of moxidectin, an experimental antiparasitic macrocyclic lactone, was evaluated in a group of 15 calves harboring naturally acquired gastrointestinal nematodes. Three groups of 5 calves each served as untreated controls (group 1) or principals that were given moxidectin PO at the rate of 0.2 mg/kg (group 2) or 0.4 mg/kg (group 3) of body weight. Equal numbers of control and treated calves were necropsied for parasite recovery on days 10 (3 control and 3 of each treatment group) and 11 (2 control and 2 of each treatment group) after treatment. Efficacies at both doses were greater than 99.8 and 99.9% against active and inhibited larvae and adults of Ostertagia spp, respectively. The overall mean efficacy of each dose was greater than 99.9%.

Topics: Administration, Oral; Animals; Anthelmintics; Anti-Bacterial Agents; Cattle; Cattle Diseases; Evaluation Studies as Topic; Feces; Intestinal Diseases, Parasitic; Macrolides; Nematode Infections; Parasite Egg Count

The efficacy of milbemycin oxime was evaluated at dosages of 0.25, 0.50, and 0.75 mg/kg of body weight in dogs naturally infected with mature Ancylostoma spp, at a dosage of 0.50 mg/kg in dogs with experimentally induced immature and mature A caninum, and at dosages of 0.55 to 0.86 mg/kg in dogs naturally infected with mature Trichuris vulpis. Milbemycin oxime was 95 and 99% effective against mature Ancylostoma spp at dosages of 0.50 and 0.75 mg/kg, respectively, but only 49% effective at a dosage of 0.25 mg/kg. Efficacy was 49% against pulmonary L3-L4 stages of A caninum (36 hours after inoculation), greater than 80% against L4 (120 hours after inoculation) and early L5 stages (216 hours after inoculation), and greater than 90% against experimentally induced mature stages (360 hours after inoculation). Milbemycin oxime was also 97% effective in the removal of mature Tr vulpis from naturally infected dogs. Adverse reactions were not observed following treatment in any of the dogs.

Topics: Ancylostomiasis; Animals; Anthelmintics; Anti-Bacterial Agents; Dog Diseases; Dogs; Feces; Female; Intestinal Diseases, Parasitic; Macrolides; Male; Parasite Egg Count; Trichuriasis

Gastrointestinal nematodes are parasites that commonly infect dogs, and infections can be subclinical or may cause considerable clinical disease. Some species are zoonotic and may also cause clinical disease in humans. Year-round treatment of dogs is recommended to eliminate existing infections, which also indirectly reduces the potential for subsequent human exposure to zoonotic species. Here we present two studies that evaluated the safety and efficacy of a novel chewable oral tablet containing sarolaner, moxidectin and pyrantel against gastrointestinal nematode infections in dogs presented as veterinary patients in Europe and the USA.. Dogs naturally infected with Toxocara canis, Toxascaris leonina, Ancylostoma caninum and/or Uncinaria stenocephala were enrolled in the European study, and dogs naturally infected with T. canis were enrolled in the USA study. The animals were treated once orally with Simparica Trio™ tablets to provide 1.2-2.4 mg/kg sarolaner, 24-48 µg/kg moxidectin and 5-10 mg/kg pyrantel (as pamoate salt) or with a commercially available product according to the label directions as positive control. Efficacy was based on the post-treatment reduction in geometric mean egg counts (per gram feces) 7 or 10 days after treatment compared to pre-treatment egg counts.. Simparica Trio™ was well tolerated in both studies. In the European study, geometric mean egg counts for T. canis, T. leonina, A. caninum and U. stenocephala were reduced by ≥ 98.3% in the Simparica Trio™ group and by ≥ 97.4% in the afoxolaner + milbemycin oxime group. In the USA study, geometric mean egg counts for T. canis were reduced by 99.2% in the Simparica Trio™ group and by 98.6% in the ivermectin + pyrantel group. In the USA study, 48 and 10 dogs in the Simparica Trio™ and the ivermectin + pyrantel group, respectively, were co-infected with A. caninum and the reduction in the post-treatment mean fecal egg counts were 98.6% and 74.7%, respectively.. A single oral administration of Simparica Trio™ chewable tablets was well tolerated and was effective in the treatment of dogs with naturally occurring gastrointestinal nematode infections presented as veterinary patients in Europe and the USA.

Topics: Administration, Oral; Animals; Antinematodal Agents; Azetidines; Dog Diseases; Dogs; Drug Combinations; Europe; Female; Intestinal Diseases, Parasitic; Macrolides; Male; Nematoda; Nematode Infections; Parasite Egg Count; Pyrantel; Spiro Compounds; Treatment Outcome; United States

Ascarid infections are among the most prevalent intestinal parasitic infections occurring in dogs around the world, with Toxocara canis and Toxascaris leonina commonly observed. Toxocara canis can cause considerable disease in dogs and humans, and year-round prophylactic treatment and control in dogs is recommended. Elimination of immature stages of these parasites before egg-laying will reduce environmental contamination and the risk of infection for both dogs and humans. Studies were conducted to evaluate the efficacy of a novel, oral chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against induced immature adult (L. Based on geometric mean worm counts, efficacy of the sarolaner + moxidectin + pyrantel combination was ≥ 95.2% against immature adult T. canis, ≥ 97.3% against adult T. canis, and ≥ 89.7% against adult T. leonina. There were no treatment-related adverse events in any study.. These studies confirm the efficacy of a single dose of a new oral chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against immature adult and adult T. canis, and adult T. leonina infections in dogs.

Topics: Administration, Oral; Animals; Antinematodal Agents; Ascaridida Infections; Azetidines; Dog Diseases; Dogs; Drug Combinations; Female; Intestinal Diseases, Parasitic; Macrolides; Male; Parasite Egg Count; Pyrantel; Spiro Compounds; Tablets; Toxascaris; Toxocara canis; Treatment Outcome

Endoparasites are considered a major health problem of South American camelids as shown in a recent survey among German and Austrian camelid owners. Although prophylactic and therapeutic measures such as application of anthelmintics are commonly used, treatment efficacy is usually not assessed. Owners have expressed significant concerns regarding the effect of antiparasitic therapy, so this study aimed to evaluate the outcome of anthelmintic treatment in German alpaca herds with different drugs.. Overall, 617 samples from 538 clinically healthy alpacas > 1 year-old from 27 farms (n = 11-157 animals/herd) were examined. The most common parasites detected by flotation were Eimeria spp. (75.1%) followed by strongylids (55.0%), Nematodirus spp. (19.3%), cestodes (3.1%) and Trichuris (2.7%). After initial coproscopical examination by flotation and strongylid egg quantification by the McMaster technique, positive animals excreting at least 150 eggs per gram of faeces were included in a faecal egg count reduction test (FECRT) using fenbendazole (n = 71 samples), moxidectin (n = 71) or monepantel (n = 66). Pre-treatment larval cultures (n = 23 positive pooled farm samples) revealed Haemonchus (87% of the farms), Cooperia (43.5%), Trichostrongylus (21.7%), Ostertagia (13.0%), Nematodirus and Oesophagostomum (4.3% each). Fenbendazole treatment reduced egg excretion by 45%, moxidectin by 91% and monepantel by 96%. On the farm level, 13/18 farms that used fenbendazole, 6/6 farms that used moxidectin and 2/5 farms that used monepantel had individual FECR values < 90% (fenbendazole) or < 95% (moxidectin, monepantel). Haemonchus and Cooperia were overrepresented on the farms with reduced treatment efficacy.. Gastrointestinal strongylids are common in German alpacas and fenbendazole in particular was not sufficiently effective to reduce strongylid egg excretion. Although the FECRT could not unambiguously determine anthelmintic resistance in the present study, the finding that small ruminant strongylids, especially Haemonchus, are common in alpacas indicates that determination of effective anthelmintic doses, monitoring of efficacy and adapted (selective) treatment regimens must be implemented as part of sustainable deworming practices in this species in accordance with recommendations for ruminants.

Topics: Aminoacetonitrile; Animals; Anthelmintics; Camelids, New World; Feces; Female; Fenbendazole; Haemonchus; Helminthiasis, Animal; Intestinal Diseases, Parasitic; Macrolides; Male; Parasite Egg Count; Strongylida; Strongylida Infections

A growing body of evidence, particularly in humans and rodents, supports the existence of a complex network of interactions occurring between gastrointestinal (GI) helminth parasites and the gut commensal bacteria, with substantial effects on both host immunity and metabolic potential. However, little is known of the fundamental biology of such interactions in other animal species; nonetheless, given the considerable economic losses associated with GI parasites, particularly in livestock and equines, as well as the global threat of emerging anthelmintic resistance, further explorations of the complexities of host-helminth-microbiota interactions in these species are needed. This study characterises the composition of the equine gut commensal flora associated with the presence, in faecal samples, of low (Clow) and high (Chigh) numbers of eggs of an important group of GI parasites (i.e. the cyathostomins), prior to and following anthelmintic treatment. High-throughput sequencing of bacterial 16S rRNA amplicons and associated bioinformatics and statistical analyses of sequence data revealed strong clustering according to faecal egg counts (P = 0.003). A trend towards increased populations of Methanomicrobia (class) and Dehalobacterium (genus) was observed in Clow in comparison with Chigh. Anthelmintic treatment in Chigh was associated with a significant reduction of the bacterial Phylum TM7 14 days post-ivermectin administration, as well as a transient expansion of Adlercreutzia spp. at 2 days post-treatment. This study provides a first known insight into the discovery of the intimate mechanisms governing host-parasite-microbiota interactions in equines, and sets a basis for the development of novel, biology-based intervention strategies against equine GI helminths based on the manipulation of the commensal gut flora.

Topics: Animals; Anthelmintics; Feces; Gastrointestinal Microbiome; Horse Diseases; Horses; Intestinal Diseases, Parasitic; Ivermectin; Macrolides; Parasite Egg Count; Strongylida Infections; Strongyloidea; United Kingdom

In a survey involving 34 sheep flocks spread over the Netherlands anthelmintic resistance (AR), based on a fecal egg count reduction (FECR) test, was determined for six different products. The study was conducted in ewes shortly after lambing during spring 2015. A FECR of less than 90%, indicating presence of AR against one or more nematode genera producing strongylid eggs, was found in 22 of 30 (73.3%) flocks against oxfendazole, 18 of 23 (78.3%) flocks against ivermectin, 15 of 32 (46.9%) flocks against moxidectin, and 2 of 26 (7.7%) flocks against monepantel. No AR was observed against levamisole. If oxfendazole resistance was observed, Haemonchus contortus was involved in 90.5% of the cases. If resistance against ivermectin, moxidectin or monepantel was observed, it invariably involved H. contortus. In the majority of cases resistance was also observed for Teladorsagia circumcincta and/or Trichostrongylus spp, between which no distinction was made in this study. Based on FECR 9 of 15 (60.0%) flocks showed resistance against closantel, which was mainly due to closantel not being effective against most other nematode species than H. contortus. However, in 44.4% of flocks showing reduced FECR it did involve H. contortus as well. Multi-drug resistance (excluding closantel) was found in 16 flocks, of which 8 showed resistance against 2 products, 7 against 3 products and 1 flock showed resistance against 4 products. If resistance against 3 or 4 products was present, there invariably was resistance against both ivermectin and moxidectin. Overall, of the 22 flocks in which both macrocyclic lactones (ML) were tested, 4 (18.2%) showed no resistance against both products, 9 (40.9%) showed resistance against ivermectin only, and 9 (40.9%) showed resistance against both MLs. It is concluded that AR is widespread in sheep in the Netherlands and involves products from all major anthelmintic classes, with possibly the exception of levamisole. It appears that the macrocyclic lactones have lost much of their efficacy against sheep nematodes over the last decade.

Topics: Aminoacetonitrile; Animals; Anthelmintics; Benzimidazoles; Drug Resistance; Feces; Haemonchiasis; Haemonchus; Intestinal Diseases, Parasitic; Ivermectin; Levamisole; Macrolides; Parasite Egg Count; Salicylanilides; Sheep; Sheep Diseases

Gastrointestinal nematodes resistant to anthelmintics have been reported in several regions of Brazil, and they may be associated with economic losses for the cattle industry. This study aimed to evaluate the resistance status of gastrointestinal nematodes from naturally infected beef cattle to several commercially available anthelmintics, as well as to test the efficacy of combinations of anthelmintics against multi-resistant gastrointestinal nematodes. Ten farms located in Rio Grande do Sul state were selected by: farmers' consent; extensive raising system; availability of calves aged from 7 to 9 months naturally infected by gastrointestinal nematodes; absence of anthelmintic treatment for 60 days before the study; and presence of 70-100 calves or more of both genders with ≥ 200 eggs per gram of feces (EPG) (sensitivity of 50 EPG). These calves were distributed into 10 groups (of 7-10 animals) per farm and treated with ivermectin, doramectin, eprinomectin, fenbendazole, closantel, nitroxynil, disophenol, levamisole, albendazole, or moxidectin. Feces were collected 2 days before treatment and 14 days after treatment. Additional groups of 7-10 calves were used to test six different two-drug combinations at four of the studied farms. In general terms, fenbendazole was the most effective drug, followed by levamisole, disophenol, and moxidectin. However, parasite resistance to multiple drugs was found in all herds, especially in the genera Cooperia spp., Trichostrongylus spp., and Haemonchus spp.. Some of the two-drug combinations were effective against nematode populations identified as resistant to the same compounds when used as single drugs. The most effective combinations were moxidectin + levamisole, doramectin + fenbendazole, and levamisole + closantel. In this study, parasites resistant to the main commercially available anthelmintics were found in all herds, and some combinations of two active components belonging to different chemical groups were effective against multi-drug resistant gastrointestinal nematodes.

Topics: Albendazole; Animals; Animals, Domestic; Antinematodal Agents; Brazil; Cattle; Cattle Diseases; Drug Resistance, Multiple; Drug Therapy, Combination; Feces; Fenbendazole; Haemonchus; Intestinal Diseases, Parasitic; Intestines; Ivermectin; Levamisole; Macrolides; Nematoda; Nematode Infections; Parasite Egg Count; Red Meat; Salicylanilides

To elucidate the molecular mechanism of host resistance, we characterized the jejunal transcriptome of Angus cattle selected for parasite resistance for over 20 years in response to infection caused by the intestinal worm Cooperia oncophora. The transcript abundance of 56 genes, such as that of mucin 12 (MUC12) and intestinal alkaline phosphatase (ALPI), was significantly higher in resistant cattle. Novel splicing variants, exon skipping events, and gene fusion events, were also detected. An algorithm for the reconstruction of accurate cellular networks (ARACNE) was used to infer de novo regulatory molecular networks in the interactome between the parasite and host. Under a combined cutoff of an error tolerance (ϵ = 0.10) and a stringent P-value threshold of mutual information (1.0 × 10(-5)), a total of 229,100 direct interactions controlled by 20,288 hub genes were identified. Among these hub genes, 7651 genes had ≥ 100 direct neighbors while the top 9778 hub genes controlled more than 50% of total direct interactions. Three lysozyme genes (LYZ1, LYZ2, and LYZ3), which are co-located in bovine chromosome 5 in tandem and are strongly upregulated in resistant cattle, shared a common regulatory network of 55 genes. These ancient antimicrobials were likely involved in regulating host-parasite interactions by affecting host gut microbiome. Notably, ALPI, known as a gut mucosal defense factor, controlled a molecular network consisting 410 genes, including 14 transcription factors (TF) and 10 genes that were significantly regulated in resistant cattle. Several large regulatory networks were controlled by TF, such as STAT6, SREBF1, and ELF4. Gene ontology (GO) processes significantly enriched in the regulatory network controlled by STAT6 included lipid metabolism. Our findings provide insights into the immune regulation of host-parasite interactions and the molecular mechanisms of host resistance in cattle.

Topics: Animals; Antinematodal Agents; Cattle; Cattle Diseases; Feces; Female; Fenbendazole; Gene Expression Profiling; Gene Regulatory Networks; Genetic Predisposition to Disease; Intestinal Diseases, Parasitic; Intestine, Small; Macrolides; Male; Parasite Egg Count; Protein Isoforms; RNA, Messenger; Trichostrongyloidea; Trichostrongyloidiasis

The effect of maize grain supplementation on the resilience and resistance of browsing Criollo goat kids against gastrointestinal nematodes was evaluated. Five-month-old kids (n = 42), raised worm-free, were allocated to five groups: infected + not supplemented (I-NS; n = 10), infected + maize supplement at 108 g/d (I-S108; n = 8), maize supplement at 1% of body weight (BW) (I-S1%; n = 8), maize supplement at 1.5% BW (I-S1.5%; n = 8), or infected + supplemented (maize supplement 1.5% BW) + moxidectin (0.2 mg/kg BW subcutaneously every 28 d) (T-S1.5%; n = 8). Kids browsed daily (7 h) in a tropical forest for 112 days during the rainy season. Kids were weighed weekly to adjust supplementary feeding. Hematocrit (Ht), hemoglobin (Hb), and eggs per gram of feces were determined fortnightly. On day 112, five goat kids were slaughtered per group to determine worm burdens. Kids of the I-S1.5% group showed similar body-weight change, Ht and Hb, compared to kids without gastrointestinal nematodes (T-S1.5%), as well as lower eggs per gram of feces and Trichostrongylus colubriformis worm burden compared to the I-NS group (P > 0.05). Thus, among the supplement levels tested, increasing maize supplementation at 1.5% BW of kids was the best strategy to improve their resilience and resistance against natural gastrointestinal nematode infections under the conditions of forage from the tropical forest.

Topics: Anemia; Animal Feed; Animals; Anthelmintics; Disease Resistance; Female; Food, Fortified; Forests; Gastrointestinal Diseases; Goat Diseases; Goats; Helminthiasis, Animal; Intestinal Diseases, Parasitic; Larva; Macrolides; Male; Mexico; Nematode Infections; Parasite Egg Count; Random Allocation; Seasons; Trichostrongylosis; Zea mays

The efficacy of moxidectin administered by different routes, against naturally acquired infections of gastrointestinal nematode parasites of cattle, was compared using faecal egg count reduction tests on 14 commercial farms throughout New Zealand. On each farm, groups of 15 calves were sampled for faecal nematode egg count and then treated with ivermectin administered orally, or with moxidectin administered either by the oral, subcutaneous injection or topical (pour-on) route. Samples were again collected 14 days after treatment and efficacy was calculated as the percentage reduction in-group mean egg count between the pre- and post-treatment samples. In addition, efficacy was calculated for individual animals, in order to compare the variability of the different treatments. On four farms untreated control groups were run and five animals from each of the control and all of the moxidectin-treated groups were bled over time to estimate plasma-moxidectin concentrations. Averaged across all tests, the reduction in faecal egg count was significantly greater after treatment with moxidectin oral (91.1%) than following treatment with moxidectin injection (55.5%) or with moxidectin pour-on (51.3%). Low efficacies were invariably against Cooperia oncophora. The oral treatments were significantly less variable in efficacy than the injection and pour-on treatments. Moxidectin concentrations in plasma were highest following subcutaneous injection and lowest following pour-on administration. Plasma levels following oral administration were intermediate, being significantly lower than post-injection and significantly higher than post-pour-on. There was no evidence of transfer of moxidectin to untreated animals through licking. Based on these results, along with those of other studies, it is proposed that oral administration of macrocyclic lactone anthelmintics results in higher concentrations of active reaching the target worms in the gastrointestinal tract than following either administration by injection or by pour-on.

Topics: Administration, Oral; Administration, Topical; Animals; Anthelmintics; Cattle; Cattle Diseases; Female; Injections; Intestinal Diseases, Parasitic; Macrolides; Male; Nematoda; New Zealand; Parasite Egg Count; Treatment Outcome

Milbemectin is a widely used veterinary antiparasitic agent. A high-performance liquid chromatography with fluorescent detection (HPLC-FLD) method is described for the determination of milbemectin in dog plasma. The derivative procedure included mixing 1-methylimizole [MI, MI-ACN (1:1, v/v), 100 microL], trifluoroacetic anhydride [TFAA, TFAA-ACN (1:2, v/v), 150 microL] with a subsequent incubation for 3s at the room temperature to obtain a fluorescent derivative, which is reproducible in different blood samples and the derivatives proved to be stable for at least 80 h at room temperature. HPLC method was developed on C18 column with FLD detection at an excitation wavelength of 365 nm and emission wavelength of 475 nm, with the mobile phase consisting of methanol and water in the ratio of 98:2 (v/v). The assay lower limit of quantification was 1 ng/mL. The calibration curve was linear over concentration range of 1-200 ng/mL. The intra- and inter-day accuracy was >94% and precision expressed as % coefficient of variation was <5%. This method is specific, simple, accurate, precise and easily adaptable to measure milbemycin in blood of other animals.

Topics: Animals; Anthelmintics; Chromatography, High Pressure Liquid; Dog Diseases; Dogs; Intestinal Diseases, Parasitic; Macrolides; Sensitivity and Specificity

The aim of the present paper was to assess benefit of strategic anthelmintic treatments on milk production in six commercial dairy sheep farms, located in southern Italy, whose animals were naturally infected with gastrointestinal strongyles. On each farm, two similar groups were formed, one untreated control group and one treated group. In all the treated groups, the strategic anthelmintic schemes were based on: (i) only one treatment with moxidectin in the periparturient period (February, Farm No. 6), or; (ii) two treatments, i.e. the first with moxidectin performed in the periparturient period (February, Farms Nos. 1, 2, 3 and 4) or in the postparturient period (April, Farm No. 5), and the second with netobimin at the mid/end of lactation (June, Farms Nos. 1, 2, 3, 4 and 5). Faecal egg count reduction (FECR) tests were performed on each farm in order to asses the anthelmintic efficacy of the drugs used. In addition, milk yield measurements for each animal fortnightly in each farm for the lactation period were performed. In terms of FECR, both moxidectin and netobimin were effective in all the 6 studied farms. Regarding milk production, overall in the 6 study farms the mean daily milk productions of the treated groups were higher than those of the control group. However, there were important differences between the 6 farms, i.e. the increase of milk production in the treated groups versus the control groups was as follows: +18.9% (Farm 1), +30.4% (Farm 2), +4.0% (Farm 3), +37.0% (Farm 4), +5.5% (Farm 5) and +40.8% (Farm 6). The results of the study showed that the economic efficacy of an anthelmintic treatment is not a cause-effect issue, but is a multifactorial issue which depends upon the quali-quantitative parasitological status of the animals, the pathogenesis of the species of parasites, the virulence of the strains of parasites, the local epidemiology, the timing of treatment, the breed of animal in terms of genetics and production types, nutrient supply.

Topics: Animals; Anthelmintics; Comorbidity; Dairying; Drug Evaluation; Female; Guanidines; Helminthiasis, Animal; Intestinal Diseases, Parasitic; Italy; Lactation; Macrolides; Parasite Egg Count; Pregnancy; Pregnancy Complications, Infectious; Puerperal Disorders; Sheep; Sheep Diseases; Strongylida Infections

The objective was to determine the effect of supplementary feeding on the resilience and resistance of Criollo kids against natural gastrointestinal nematode (GIN) infections, when browsing native vegetation during the dry season in tropical Mexico. Thirty-three two-month-old Criollo kids, raised nematode free, were included at weaning in a 20-week trial. The kids were placed into four groups. Two groups of eight kids were offered 100g/day soybean and sorghum meal (26%:74% respectively fresh basis) (treated/supplemented (T-S) and infected/supplemented (I-S)). Two groups remained with no supplement for the duration of the trial (infected/non-supplemented (I-NS) (n=9) and treated/non-supplemented (T-NS) (n=8)). Kids in groups T-S and T-NS were drenched with 0.2mg of moxidectin/kg body weight orally (Cydectin, Fort Dodge) every 28 days. Groups I-S and I-NS were naturally infected with GIN. The animals browsed native vegetation for an average of 7h/day together with a herd of 120 naturally infected adult goats. Cumulative live weight gain (CLWG), packed cell volume (PCV), haemoglobin (Hb), total plasma protein and plasma albumin were recorded every 14 days as measurements of resilience. Resistance parameters (faecal egg counts (FEC) and peripheral eosinophil counts (PEC)) were also measured. Bulk faecal cultures were made for each group every 28 days. Every month a new pair of initially worm-free tracer kids assessed the infectivity of the vegetation browsed by the animals. Tracer kids and faecal cultures showed that kids faced low mixed infections (Haemonchus contortus, Trichostrongylus colubriformis and Oesophagostomum columbianum). Under conditions of scarce vegetation, such as those in the present study, supplemented groups (I-S and T-S) had higher growth rates compared to the non-supplemented groups independently of the control of GIN infection with anthelmintic (AH) treatment (P<0.001). Supplementary feeding did not affect FEC or PEC. In the absence of supplementation, lack of AH treatment may lead to outbreaks of clinical nematodosis. The supplementary feeding was economically feasible.

Topics: Animal Nutritional Physiological Phenomena; Animals; Antinematodal Agents; Diet; Dietary Supplements; Feces; Goat Diseases; Goats; Hematocrit; Hemoglobins; Host-Parasite Interactions; Intestinal Diseases, Parasitic; Leukocyte Count; Macrolides; Mexico; Nematoda; Parasite Egg Count; Seasons; Strongylida Infections; Weight Gain

Topics: Animals; Antinematodal Agents; Horse Diseases; Horses; Intestinal Diseases, Parasitic; Larva; Life Cycle Stages; Macrolides; Metastrongyloidea; Strongylida Infections

Sixteen controlled laboratory studies, involving 420 kittens and cats, were conducted to evaluate the efficacy and safety of topically applied formulations of imidacloprid and moxidectin for the prevention of feline heartworm disease, treatment of flea infestations and treatment and control of intestinal nematodes. Unit-dose applicators and the dosing schedule used in these studies were designed to provide a minimum of 10mg imidacloprid and 1mg moxidectin/kg. Treatments were applied topically by parting the hair at the base of the skull and applying the solution on the skin. Imidacloprid treatment alone did not display activity against Dirofilaria immitis or intestinal nematodes and moxidectin treatment alone provided little or no activity against adult Ctenocephalides felis infestations. The formulation containing 10% imidacloprid and 1% moxidectin was 100% efficacious against the development of adult D. immitis infections when cats were treated 30 days after inoculation with third-stage larvae. A single treatment with this formulation also provided 88.4-100% control of adult C. felis for 35 days. Imidacloprid/moxidectin was 100% efficacious against adult Toxocara cati and 91.0-98.3% efficacious against immature adults and fourth-stage T. cati larvae. The formulation provided 98.8-100% efficacy against adult Ancylostoma and immature adults and third-stage A. tubaeforme larvae. Monthly topical application with 10% imidacloprid/1% moxidectin is convenient, efficacious and safe for the prevention of feline heartworm disease, treatment of flea infestation and for the treatment and control of intestinal nematode infections of cats.

Topics: Administration, Topical; Animals; Antinematodal Agents; Cat Diseases; Cats; Dirofilariasis; Dose-Response Relationship, Drug; Drug Administration Schedule; Ectoparasitic Infestations; Female; Filaricides; Imidazoles; Insecticides; Intestinal Diseases, Parasitic; Life Cycle Stages; Macrolides; Male; Nematode Infections; Neonicotinoids; Nitro Compounds; Treatment Outcome

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 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.

Topics: Animals; Anthelmintics; Belgium; Body Weight; Cattle; Cattle Diseases; Diarrhea; Feces; Female; Injections, Subcutaneous; Intestinal Diseases, Parasitic; Macrolides; Nematoda; Nematode Infections; Parasite Egg Count; Poaceae; Random Allocation

Four trials, three in the United States and one in South Africa, were conducted to evaluate the potential value of a novel self-medicating applicator in the passive control of gastrointestinal nematodes in cattle and deer, and of files and ticks on cattle using oil-based treatments. The results of the trials demonstrated that this applicator is an effective and practical device for the passive treatment of both deer and cattle for trichostrongyle infections using the endectocide, moxidectin (Cydectin. Fort Dodge Animal Health, USA), of cattle for hom fly (Haemotobia irritans) infestations using the insecticide, cyfluthrin (CyLence, Bayer AG, Germany) and of cattle for tick infestations (in particular Amblyomma hebraeum and Rhipicephalus appendiculatus) using the acaricides deltamethrin and amitraz (Delete All, Intervet, South Africa).

Topics: Administration, Topical; Animals; Animals, Domestic; Animals, Wild; Anthelmintics; Cattle; Deer; Drug Combinations; Ectoparasitic Infestations; Female; Insecticides; Intestinal Diseases, Parasitic; Macrolides; Male; Nematode Infections; Nitriles; Pesticide Synergists; Piperonyl Butoxide; Pyrethrins; Random Allocation; Tick Control; Tick Infestations; Toluidines

Sixty-four Romney ewe lambs were allocated to 12 groups on the basis of liveweight. Four groups (n=5) were administered oral ivermectin (IVM), 4 (n=6) oral moxidectin (MOX) and the remaining 4 (n=5) controlled-release capsules containing IVM (IVM-CRCs). Nine and 10 days later, the groups within each treatment type were challenged with infective-stage larvae (L3) of 1 of 4 different isolates of Teladorsagia circumcincta (two doses each of 5000 L3). The first of these (S) was known to be anthelmintic-susceptible; the second (OR) was a multiple anthelmintic-resistant strain recovered from the field following therapeutic failure of both ivermectin and moxidectin and subsequently maintained in the laboratory without further anthelmintic selection; the third (R) was derived from OR but had been passaged for five generations indoors with each generation being screened with all three broad-spectrum anthelmintic classes; and the fourth (RxS) was an F1 cross between the R and S isolates. As anticipated, because of its limited residual activity, IVM had no significant effect on the establishment, 9 and 10 days post-treatment, of any of the parasite isolates. In contrast MOX, which has greater residual activity, was highly effective at preventing the establishment of the S isolate but showed no significant effect against the OR, R or RxS isolates. The IVM-CRC was also highly effective at preventing the establishment of the S isolate and furthermore it significantly reduced establishment of both the OR and RxS isolates, although it had no significant effect against the R isolate. The results suggest that with respect to the establishment of T. circumcincta L3s following anthelmintic treatment, macrocyclic lactone (ML) resistance is effectively a dominant trait in the presence of MOX, while it behaves as a partially dominant/recessive trait under treatment with IVM-CRCs. The potential implications of this finding in relation to selection for ML resistance in T. circumcincta are discussed.

Topics: Abomasum; Administration, Oral; Animals; Anthelmintics; Delayed-Action Preparations; Drug Resistance; Feces; Female; Intestinal Diseases, Parasitic; Ivermectin; Macrolides; Ostertagia; Ostertagiasis; Parasite Egg Count; Random Allocation; Sheep; Sheep Diseases

The helminth burdens and biodiversity of 9 randomly selected donkeys (Equus asinus) were examined after necropsy. Prior to necropsy, 8 of the animals were subjected to 1 of 3 management interventions (monthly fecal removal, prewinter moxidectin treatment, and a combination of both treatments) or a control for a 16-mo period. The remaining animal was killed earlier in the study. Quantitative samples were collected from the gastrointestinal tract for helminth recovery. The intestinal walls were examined with transmural illumination and thereafter digested with a HCl-peptic method for identification of the mucosal larval stages of cyathostomes. In this study, 37 helminth species belonging to the Ascarididae, Atractidae, Dictyocaulidae. Habronematidae, Onchocercidae, Oxyuridae, Strongylidae, and Trichostrongylidae, 1 cestode species of the Anoplocephalidae, and 1 trematode species in the Paramphistomatidae were recovered. In addition, 1 species of oestrid fly of the Gasterophilidae was identified. The results obtained in the present study support the application of several intervention methods to reduce the helminth burdens in donkeys.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Cecum; Colon; Equidae; Female; Helminthiasis, Animal; Helminths; Intestinal Diseases, Parasitic; Larva; Macrolides; Male; Mucous Membrane; Parasite Egg Count; South Africa

Commercial preparations of fenbendazole (Safe-Guard, Intervet), ivermectin (Eqvalan, Merial) or moxidectin (Quest, Fort Dodge) were administered once to horses scheduled for routine parasiticide treatment. In total, 93 horses from six cooperating farms were used in the study. Computer generated, random allocation of horses to treatment group was conducted at each farm. Fecal egg counts were determined for all horses on trial days 0, 56, 84 and 112, with corresponding calendar dates that were unique to each farm. Only strongyle egg counts from animals which were positive at day 0 were used for analysis of variance and comparisons. Counts for the three treatment groups were similar at day 0, moxidectin

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Drug Resistance; Feces; Fenbendazole; Horses; Intestinal Diseases, Parasitic; Ivermectin; Macrolides; Parasite Egg Count; Random Allocation; Strongyle Infections, Equine; Strongyloidea; Time Factors; Treatment Outcome

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

Twenty crossbred beef heifer calves were used for an efficacy evaluation of 0.5% moxidectin pour-on against gastrointestinal nematodes and Dictyocaulus viviparus. The latter parasite and Bunostomum phlebotomum were the target species. The calves were exposed to natural infection on pasture from late September to December 22. Additionally, all calves were experimentally infected with B. phlebotomum at 71 and 29 days before treatment and with D. viviparus at 29 days before treatment. The 20 calves were randomly allocated into two groups of ten, based on presence of patent lungworm and hookworm infections on days -6 and -1. Treatments were as follows: Group A, moxidectin 0.5% pour-on (PO) at 500 micrograms kg-1 BW; Group B, moxidectin vehicle (controls) by PO application. General strongyle and hookworm egg counts and lungworm larval counts were reduced to zero at 13 days after moxidectin treatment; treatment effect was significant (P < 0.05) only for the strongyle and hookworm counts. Percentage reduction for adult hookworms and mature-immature adult lungworms was 100.0 and also for adults and L4 Haemonchus placei and Ostertagia ostertagi and Trichostrongylus axei adults, adult males of Cooperia pectinata and C. spatulata, and Oesophagostomum radiatum adults. Efficacy values for C. punctata adult males, Cooperia spp. adult females, and Cooperia spp. L4 were > 99.9%, > 99.9%, and 92.4%, respectively. All efficacy values were significant (alpha = 0.05, 1-sided) except for Cooperia spp. L4.

Topics: Administration, Topical; Animals; Anthelmintics; Anti-Bacterial Agents; Cattle; Cattle Diseases; Dictyocaulus Infections; Feces; Female; Intestinal Diseases, Parasitic; Macrolides; Male; Nematode Infections; Parasite Egg Count; Random Allocation

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

The efficacy of orally administered moxidectin was determined against four benzimidazole-resistant nematode isolates. At the start of the trial, 30 lambs were each infected experimentally with 20,000 third stage larvae (5000 Haemonchus contortus, 7000 Teladorsagia circumcincta, 3000 Trichostrongylus colubriformis and 5000 Cooperia curticei); 28 days later they were allocated randomly to three groups of 10: one untreated group, one group treated orally with fenbendazole (5 mg/kg bodyweight) and one group treated orally with moxidectin (0.2 mg/kg). Samples of faeces were taken five and 10 days after treatment and the lambs were killed 10 days after treatment. Fenbendazole reduced the average number of nematode eggs in faeces by 95 per cent and the average number of worms by 25 to 45 per cent according to the species. The efficacy of moxidectin against these benzimidazole-resistant isolates was 100 per cent. No adverse reactions to either of the drugs were observed.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Benzimidazoles; Drug Resistance; Feces; Haemonchiasis; Intestinal Diseases, Parasitic; Macrolides; Male; Nematode Infections; Parasite Egg Count; Sheep; Sheep Diseases; Trichostrongyloidiasis; Trichostrongylosis

The activity of an oral drench of moxidectin against nematodes in naturally infected sheep known to harbour Nematodirus species was evaluated at doses of 0.2 and 0.4 mg/kg bodyweight. Moxidectin was 100 per cent effective against nematodes in the abomasum and 100 per cent effective against nematodes in the small intestine except for adult Trichostrongylus species, against which its efficacy was 94 per cent. It was 100 per cent effective against nematodes in the large intestine except for Trichuris ovis, against which its efficacy was 83 per cent.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Intestinal Diseases, Parasitic; Macrolides; Nematoda; Nematode Infections; Parasite Egg Count; Sheep; Sheep Diseases

The efficacy of moxidectin against gastrointestinal nematode infections was studied in 30 Fleischschaf x Rasa Aragonesa male lambs aged 3 months at the beginning of the experiment. The lambs were distributed in three groups of 10 animals each and experimentally infected with a mixture of an equal number of infective (L3) larvae from each of the following species: Haemonchus contortus (2000), Ostertagia circumcincta (2000), Trichostrongylus colubriformis (2000) and Trichostrongylus vitrinus (2000). Two groups of lambs were drenched with 0.2 mg moxidectin per kg body weight at 6 (Group B) and 21 (Group C) days post challenge while the third group of animals (Group A) remained untreated. The efficacy of the treatment based on worm counts 4 weeks post infection was of 100% against 4th stage larvae of all species and 100%, 99.98%, 100% and 100% against adults of H. contortus, O. circumcincta, T. colubriformis and T. vitrinus, respectively. Significant differences were found in daily weight gain between treated (Group B+C, 157.9 g day-1) and untreated lambs (Group A, 116 g day-1). No differences in feeding behaviour or health condition between treated and untreated lambs were observed.

Topics: Abomasum; Administration, Oral; Animals; Anthelmintics; Anti-Bacterial Agents; Feces; Intestinal Diseases, Parasitic; Intestine, Small; Macrolides; Male; Nematode Infections; Parasite Egg Count; Sheep; Sheep Diseases; Weight Gain

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Feces; Female; Fenbendazole; Helminthiasis; Helminthiasis, Animal; Intestinal Diseases, Parasitic; Ivermectin; Macrolides; Parasite Egg Count; Pregnancy; Puerperal Infection; Sheep; Sheep Diseases; Time Factors

Twenty male Holstein calves averaging 105 kg in weight and naturally infected with gastrointestinal nematodes and small numbers of lungworm and hookworm, were given experimental infections with the two latter species to provide adult and larval stages for anthelmintic evaluation. Following random allotment, one group of 10 calves was injected subcutaneously with moxidectin at a dosage of 0.2 mg kg-1 of body weight. A second group of 10 was injected subcutaneously with unmedicated blank vehicle at a dosage of 1 ml per 50 kg of body weight. Fecal samples were examined before treatment and at 7 and 13 days after treatment. The 20 calves were necropsied for worm recovery at 13 and 14 days after treatment. All calves were positive for lungworm and hookworm on the treatment date. Treatment was 100% effective in elimination of hookworm eggs and lungworm larvae and 99.9% in reducing total egg counts at both 7 and 13 days after treatment. Moxidectin was 100% effective (P less than 0.01) in eliminating the following 11 species of nematodes. Dictyocaulus viviparus mature and immature adults (E5), Bunostomum phlebotomum adults and L4, Ostertagia ostertagi adults and early L4, Ostertagia lyrata adult males, Haemonchus placei adults. Trichostrongylus axei adults, Cooperia spp., including Cooperia punctata, Cooperia spatulata, and Cooperia pectinata adults, Oesophagostomum radiatum adults and Trichuris discolor adults. No adverse reactions to moxidectin treatment were observed.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Cattle; Cattle Diseases; Dictyocaulus Infections; Feces; Hookworm Infections; Injections, Subcutaneous; Intestinal Diseases, Parasitic; Macrolides; Male; Nematode Infections; Parasite Egg Count; Random Allocation

Three groups of 11 naturally infected crossbred beef calves were injected subcutaneously with moxidectin 1 per cent injectable at 0.2 or 0.3 mg moxidectin/kg bodyweight or with the unmedicated vehicle. Nematode infections had been acquired during grazing from December to April. Based on the faecal egg counts and total worm counts of the control calves at necropsy (11 to 13 days after treatment) most of the calves had heavy parasitic burdens. Ostertagia ostertagi was predominant and the mean numbers of adults, developing fourth stage larvae (L4) and inhibited early L4 were 45,906, 10,061 and 68,918, respectively. Haemonchus placei and Trichostrongylus axei were also present in the abomasa. Three species of Cooperia, Oesophagostomum radiatum L4 and T colubriformis adults were found in the intestinal tract. Both dosages of moxidectin were equally effective (P < 0.05) against all the abomasal nematodes (99.9 to 100 per cent) and the intestinal tract nematodes (99.4 to 100 per cent). No adverse reactions to the moxidectin treatment were observed. Abomasal pathology characteristic of heavy O ostertagi infection was observed in the control calves, but not in the treated calves.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Cattle; Cattle Diseases; Feces; Female; Haemonchiasis; Intestinal Diseases, Parasitic; Macrolides; Nematode Infections; Oesophagostomiasis; Ostertagiasis; Parasite Egg Count; Trichostrongyloidiasis; Trichostrongylosis

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Dirofilariasis; Dog Diseases; Dogs; Female; Intestinal Diseases, Parasitic; Macrolides; Male; Nematode Infections