Use of fenbendazole suspension (10%) against experimental infections of Toxocara canis and Ancylostoma caninum in beagle pups

Eleven nematode-free Beagle pups were inoculated with Ancylostoma caninum and Toxocara canis; infection became patent 13 and 35 days later, respectively. Eight pups were treated with fenbendazole oral suspension (10%) at a dosage of 50 mg/kg of body weight/day for 3 days. The remaining three animals were unmedicated controls. The drug was effective in reducing both ascarid and hookworm burdens, and there was marked improvement in the clinical condition of treated pups as compared with unmedicated control pups. Natural expulsion of worms in control animals was 53% for ascarids and 2% for hookworms. Drug-related toxicosis was not observed in any of the medicated animals. It was concluded that fenbendazole oral suspension (10%) at the 50-mg/kg dosage is easily administered and is an effective drug for reducing nematode burdens in experimentally infected pups.     

Effect of fenbendazole on Toxocara canis larvae in tissues of infected dogs.

The effect of fenbendazole therapy was studied in six dogs fed 10,000 embryonated Toxocara canis eggs. At 47 days after they were fed T canis, four dogs were given fenbendazole in two divided doses totaling 50 mg/kg of body weight each day for 14 days. Two infected dogs were not given fenbendazole. All dogs were necropsied at the end of treatment and the foci were counted in the lungs; their skeletal muscles were digested in 1% trypsin for the recovery of larvae. The T canis larvae were not recovered from the skeletal muscle of the four infected dogs treated with fenbendazole; 15 and 42 larvae/100 g of skeletal muscle were recovered from the two nonmedicated infeected dogs. The number of grossly visible foci on surfaces of lungs in treated dogs was markedly less than in the nonmedicated infected dogs. The results indicate that fenbendazole might be effective in preventing prenatal infection in dogs.     

Macrocyclic lactone-resistant Parascaris equorum on stud farms in Canada and effectiveness of fenbendazole and pyrantel pamoate

The aims of studies in 2002 and 2003 on three farms with 76 foals naturally infected with Parascaris equorum were to (i) identify if the nematode was resistant to ivermectin and moxidectin, and (ii) confirm the effectiveness of fenbendazole and pyrantel pamoate for the parasite. Twelve clinical trials, each with a Fecal Egg Count Reduction Test, were conducted on two Thoroughbred and one Standardbred farms in southwestern Ontario, Canada. In each trial, Parascaris eggs/g feces were estimated for each foal pre- and post-treatment using the Cornell-Wisconsin double flotation and Cornell-McMaster dilution techniques. On each farm and for each trial, foals were randomized into treatment groups. Treatments were ivermectin, moxidectin, fenbendazole, pyrantel pamoate administered at the manufacturers' recommended dosages, and some foals were untreated. The overall efficacy for ivermectin was 33.5% (19 foals) and for moxidectin 47.2% (28 foals). Fenbendazole (16 foals) and pyrantel pamoate (21 foals) were highly effective for P. equorum each at 97.6%. For fenbendazole, 15 foals had 100% and for pyrantel pamoate 17 foals had >97% with 14 at 100%.     

The efficacy of pyrantel pamoate against ascarids and hookworms in cats

The purposes of this study were to evaluate pyrantel pamoate administered orally at 20 mg/kg body weight for the removal of induced or natural infections of Ancylostoma tubaeformae and Toxocara cati in cats and to compare the efficacy of paste (40 mg base/g) and granule (80 mg base/g) formulations. Thirty cats of mixed breeding and various ages with natural and/or induced infections of A. tubaeformae and T. cati were assigned to one of three treatment groups: (1) non-medicated controls; (2) paste formulation at 20 mg base/kg; or (3) granule formulation at 20 mg base/kg. Infections were induced by feeding the cats on carcasses of infected mice. The study was conducted in replicates of at least one animal per treatment per replicate. The study parameters included clinical observations, physical examinations, faecal egg counts and the numbers, species and stages of worms recovered at necropsy. The paste formulation was 99.3% and 99.7% effective in reducing egg counts of Ancylostoma sp. and Toxocara sp. respectively. The granule formulation was 97.7% and 99.9% effective in reducing faecal egg counts of Ancylostoma sp. and Toxocara sp. respectively. When administered in paste form, pyrantel pamoate was 99.5% effective in removing adult Ancylostoma and 100.0% effective against adult Toxocara. The granule formulation was 97.9% effective against Ancylostoma and 100% effective against Toxocara. No toxic effects of either formulation of the drug were noted.     

Efficacy of an ivermectin and pyrantel pamoate combination against adult hookworm, Ancylostoma braziliense, in dogs

A chewable tablet incorporating ivermectin and pyrantel was tested in 12 Beagle dogs for efficacy against the adult hookworm, Ancylostoma braziliense. The dogs were administered infective larvae of A braziliense orally. Twenty-one days after infection the dogs were weighed and allocated randomly to receive either an oral treatment with ivermectin and pyrantel in a beef-based chewable tablet or no treatment. The chewable tablet was a commercially available product, which was made to deliver ivermectin at 6 μg/kg and pyrantel at 5.0 mg/kg to each dog. Seven days after treatment the dogs were euthanased, necropsied, and examined for adult hookworms. At necropsy, no adult A braziliense was observed in any of the 6 treated dogs and all 6 dogs that had been left untreated were infected with adult A braziliense (range, 48 to 161). It was concluded that this combination product is 100% efficacious against adult A braziliense.     

Efficacy of ivermectin and pyrantel pamoate combined in a chewable formulation against heartworm, hookworm, and ascarid infections in dogs.

Eight trials were conducted in dogs to document the efficacy of ivermectin (6 micrograms/kg of body weight) and pyrantel pamoate (5 mg of active pyrantel/kg) in a beef-based chewable formulation against Dirofilaria immitis, Ancylostoma caninum, Uncinaria stenocephala, Toxocara canis, and Toxascaris leonina. Three studies involved induced infection with D immitis, and 5 studies involved induced or natural infection with hookworms and ascarids. In 3 intestinal parasite trials, the efficacy of the combination chewable tablet was compared with each of its components. Results indicated that 1 component did not interfere with the activity of the other. In 1 heartworm and 2 intestinal parasite trials, the efficacy of pyrantel, ivermectin/pyrantel combination, or ivermectin with pyrantel dosage of 10 mg/kg was evaluated. The ivermectin/pyrantel combination was 100% effective in preventing development of D immitis larvae. Efficacy of the combined product against T canis, Toxascaris leonina, A caninum, and U stenocephala was 90.1, 99.2, 98.5, and 98.7%, respectively. In the intestinal parasite trials, each individual component was found not to interfere with the anthelmintic action of the other. Increasing the dosage of pyrantel to 10 mg/kg (2 x that in the combination) did not interfere with the efficacy of ivermectin against heartworm or increase the activity of pyrantel against intestinal parasites.     

Efficacy of an ivermectin/pyrantel pamoate chewable formulation against the canine hookworms, Uncinaria stenocephala and Ancylostoma caninum.

The effectiveness of the combination of pyrantel pamoate (5 mg kg-1) and ivermectin (6 micrograms kg-1) against the canine hookworms Uncinaria stenocephala and Ancylostoma caninum was determined. This combination is intended for monthly use as a heartworm preventative and for treatment and control of canine hookworms. The formulation was found to be effective (99.6% reduction in worm burdens) against both species of hookworms in experimentally infected dogs. No adverse effects due to the drug combination were observed in any dog during the course of this study.     

Clinical field efficacy and safety of pyrantel pamoate paste (19.13% w/w pyrantel base) against Anoplocephala spp. in naturally infected horses

Clinical field trials were conducted at five geographical locations in the USA (Oklahoma, Wisconsin, Tennessee, Virginia and Idaho) to evaluate the efficacy and safety of pyrantel pamoate paste (19.13%, w/w, pyrantel base) administered at the recommended dosage of 13.2 mg pyrantel base/kg (6.0 mg pyrantel base/lb) body weight (b.w.) against tapeworm infections of Anoplocephala spp. in naturally infected horses. Horses at each study site were allocated by restricted randomization based on the cestode status (positive or negative) of pre-treatment fecal egg counts to complete sets of four animals each or incomplete sets of fewer than four animals. Within sets comprising of two to four horses, one animal was randomly allocated to receive placebo vehicle paste and the remaining horse(s) received pyrantel pamoate paste administered orally at a minimum dosage of 13.2 mg pyrantel base/kg b.w. on Test Day (TD) 0. Single animal sets received pyrantel pamoate paste. Fecal samples of horses were collected and examined for equine tapeworm (Anoplocephala spp.) eggs a minimum of four times (once or thrice between TD -28 and -14, twice between TD -14 and -7, and once on TD 0) prior to treatment on TD 0. Fecal samples of horses that were positive for cestode infection pre-treatment were examined for cestode eggs on TD 7, 8, 9, 14, 15 and 16. Cestode-negative pre-treatment horses were not sampled again after treatment. A total of 241 horses (141 mares, 16 stallions and 84 geldings; 6 months-30 yrs of age; 173-646 kg; 13 recognized breeds and various crossbreds) were evaluated. The prevalence of Anoplocephala spp. determined by pre-treatment fecal examination ranged from 38.3% in Idaho to 68.1% in Tennessee with an overall prevalence of 52.3%. Ninety cestode-positive and 88 cestode-negative horses were treated with pyrantel pamoate paste, 36 cestode-positive and 27 cestode-negative horses were treated with placebo vehicle paste. Overall, 178 horses were treated with pyrantel pamoate paste, and 63 horses were treated with placebo paste. Of the 178 horses treated with pyrantel pamoate paste, no drug related, adverse clinical or neurological health events were observed. No doses of pyrantel pamoate paste were refused or lost during dosing. At each post-treatment time sampling interval, significantly fewer cestode eggs (P < 0.0115) were passed by cestode-positive horses treated with pyrantel pamoate paste compared to cestode-positive horses that received placebo paste. Efficacy of the pyrantel pamoate paste treatment ranged from 92 to 96% from TD 7 to TD 16 with an overall efficacy of 95%. The results of these trials demonstrated that pyrantel pamoate paste (19.13%, w/w, pyrantel base) administered orally at a dosage of 13.2 mg pyrantel base/kg b.w. is highly efficacious (95%) against Anoplocephala spp. and safe for use in horses with no adverse clinical or neurological health events observed under field use conditions.     

Efficacy of selamectin against experimentally induced and naturally acquired ascarid (Toxocara canis and Toxascaris leonina) infections in dogs

The efficacy of selamectin against adult ascarids was evaluated in eight controlled and masked studies in dogs. Three laboratory studies evaluated selamectin against experimentally induced infections of Toxocara canis; three laboratory studies evaluated selamectin against naturally acquired infections of T. canis; one laboratory study evaluated selamectin against naturally acquired infections of both T. canis and Toxascaris leonina; one field study evaluated selamectin against naturally acquired infections of ascarids (T. canis and/or T. leonina) in dogs presented as veterinary patients. Selamectin was administered topically to the skin of dogs in unit doses designed to deliver a minimum of 6mgkg(-1) (range, 6-12mgkg(-1)). In all studies, dogs were allocated randomly to treatment assignments (selamectin or vehicle control in laboratory studies: selamectin or reference product in the field study) on the basis of pretreatment fecal egg counts. For induced infections, there were significant reductions in geometric mean numbers of adult T. canis after a single application of selamectin (93.9-98.1%, P=0.0001), after two monthly applications (> or =88.3%, P< or =0.0001), and after three monthly applications (100%, P< or =0.0002). In the natural infection laboratory studies, when selamectin was administered twice at an interval of 30 days, the percentage reductions in geometric mean numbers of adult T. canis at necropsy were 84.6, 91.3, and 97.9%, and when selamectin was administered on days 0, 14, and 30, the percentage reductions were 91.1 and 97.6%. Geometric mean fecal T. canis egg counts were reduced by > or =92.9% (P< or =0.0067) at the end of the studies. In the field study, geometric mean fecal ascarid egg counts were reduced by 89.5 and 95. 5% (P=0.0001) for 14 and 30 days, respectively, after a single treatment with selamectin, and by 94.0% (P=0.0001) 30 days after the second treatment with selamectin. These reductions compared favorably with the egg count reductions from dogs treated with a reference product containing praziquantel, pyrantel embonate, and febantel. There were no adverse drug experiences or treatment-related mortalities during any of the studies. Selamectin, when administered topically in a unit dose providing a minimum dosage of 6mgkg(-1), was safe and effective against adult T. canis and T. leonina and in reducing the fecal excretion of T. canis eggs in dogs.     

Efficacy of fenbendazole against adult Dictyocaulus viviparus in experimentally infected calves.

Fenbendazole, methyl-5(phenylthio)-2-benzimidazolecarbamate, a new broad-spectrum anthelmintic, was evaluated against the adult Dictyocaulus viviparus, lungworm of cattle, in artificially infected calves. At a dosage of 5 mg/kg of body weight, fenbendazole removed 100% of the worms if given as an oral suspension, and 99.7% of the worms if given as a feed additive.     

Evaluation of a beef-based chewable formulation of pyrantel pamoate against induced and natural infections of hookworms and ascarids in dogs.

Pyrantel pamoate, formulated in a beef-based chewable tablet, was evaluated for efficacy in dogs against induced and natural infections of Toxocara canis, Toxascaris leonina, Ancylostoma caninum and Uncinaria stenocephala. Dose titration trials were conducted in Canada, the UK and Germany in dogs treated with pyrantel (as pamoate salt) at 0, 2.5, 5 or 10 mg kg-1 body weight. These studies showed that a dose rate of 2.5 mg kg-1, the efficacy of pyrantel against adult T. canis, T. leonina, U. stenocephala and A. caninum was 76.1, 85.6, 100 and 87.9%, respectively. Efficacy at 5 mg kg-1 against the same parasites was 94.2, 92.0, 93.5 and 93.8%, respectively, and at 10 mg kg-1 efficacy was 91.2, 97.6, 98.7 and 91.3%, respectively. No adverse effects due to treatment were seen in any of these trials.     

Efficacy of fenbendazole against helminth parasites of poultry in Uganda

Summary Fenbendazole 4% (Panacur, Hoechst) administered in feed was used to treat chickens infected withAscaridia galli, Heterakis gallinarum andRailletina spp. It was also used to treatSyngamus trachea in broiler birds. There was a marked drop in helminth egg counts in the faeces on the second day of treatment and the faeces became negative by the seventh day after the last treatment. Post-mortem examination 15 to 21 days later showed that the drug was 100% effective againstAscaridia galli andHeterakis gallinarum at 10 mg/kg. However, for complete removal ofRailletina spp. 15 mg/kg was required. Similarly 20 mg/kg fenbendazole was effective againstSyngamus trachea. It was concluded that fenbendazole is suitable for the treatment of the important intestinal and tracheal worms of poultry, a dose of 15 to 20 mg/kg for 3 consecutive days being recommended for use under field conditions.

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Eficacia Del Fenbendazole Contra Helmintos De Aves Domesticas En Uganda

Presumen Se administró Fenbendazole 4% (Panacur, Hoechst) en el alimento, para tratar aves infectadas conAscaridia galli, Heterakis gallinarum y Railletina spp. También se utilizó la droga para tratar pollos de engorde infectados conSyngamus trachea. Hubo un descenso marcado en el conteo de huevos de helmintos al segundo día del tratamiento, y las heces fueron negatives 7 días después del último tratamiento. El examen pos-mortem 15 y 21 días después del tratamiento mostró que la droga fue 100% efectiva contraAscaridia galli y Heterakis gallinarum en dosis de 10 mg/kg. Sin embargo, para el control deRailletina spp. 1a dosis se incrementó a 15 mg/kg. Similarmente, 20 mg/kg de Fenbendazole fueron efectivas contraSyngamus trachea. Se concluye, que el Fenbendazole es efectivo contra el tratamiento de los principales parásitos intestinales y traqueales de las aves domésticas, en dosis de 15 a 20 mg/kg, administrado por días consecutivos, en casos de campo.

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Efficacite Du Fenbendazole Contre Les Helminthes Parasites Des Volailles En Ouganda

Résumé Le Fenbendazole 4 p. 100 (Panacur, Hoechst) administré dans l'alimentation a été utilisé pour le traitement de poulets infectés parAscaridia galli, Heterakis gallinarum etRailletina spp. Il a été également utilisé contreSyngamus trachea chez les oiseaux de chair. On a observé une baisse marquée dans la numération des oeufs dans les fèces dès le deuxième jour du traitement et ces fèces étaient devenues négatives le septième jour après le dernier traitement. L'examen post-mortem pratiqué de 15 à 20 jours plus tard a montré que le produit était efficace à 100 p. 100 contreAscaridia galli etHeterakis gallinarum à 10 mg/kg. Cependant, il a fallu en arriver à la dose de 15 mg/kg pour obtenir la complète élimination deRailletina spp. De même le Fenbendazole à la dose de 20 mg/kg a été effectif contreSyngamus trachea. Il en est conclu que ce produit convient pour le traitement des helminthes intestinaux et trachéaux des volailles, la dose de 15 à 20 mg/kg pendant 3 jours consécutifs étant recommandée lors de son utilisation sur le terrain.

     

Efficacy of fenbendazole and cambendazole against Muellerius capillaris in dairy goats

Two anthelmintics, fenbendazole and cambendazole, were used in an attempt to eliminate Muellerius capillaris infections in a group of 44 goats. During the course of this study (508 days), M capillaris larvae were found in at least one fecal specimen from each of 22 of the 44 goats. All 44 goats were dewormed with fenbendazole (30 mg/kg of body weight) at the onset of this study (day 18). Two additional dewormings with fenbendazole at 4- to 8-week intervals were restricted to the goats that continued to shed M capillaris larvae. On the basis of routine fecal examinations, fenbendazole eliminated M capillaris larvae from the feces of 8 (36%) of these 22 goats. On day 253, cambendazole (60 mg/kg) was given orally to 17 of these 22 goats (2 of the 22 had died and 3 were not available for treatment); 13 of these goats were still shedding M capillaris larvae. Cambendazole eliminated M capillaris larvae from the feces of 10 (77%) of these 13 goats chronically infected with M capillaris.     

Evaluation of the efficacy of oxfendazole against larval and adult Toxocara canis in unweaned dogs

The efficacy of oxfendazole given at a dose-rate of 10 mg kg^-1 for 3 consecutive days against adult and larval Toxocara canis was determined in four litters of naturally infected unweaned greyhound pups. Comparison of the worm-burdens of four pups treated on days 30–32 post partum with four matched litter-mate untreated controls gave an apparent efficacy value of 98-5 per cent, the numbers of adult T. canis at post mortem examination being 3 and 202, respectively. A similar comparison involving 10 pups treated on the 5th to 7th days of life, when the T. canis would have been in various stages of larval development, gave an overall efficacy value of 75.8 per cent, with worm-counts of 1,325 and 321 for control and treatment groups. However, a greater reduction (84.1–91.7 per cent) was observed in worms achieving a length of 40 mm by the time of post mortem examination (Day 21 post partum) than in shorter worms. In the latter case, no demonstrable anthelmintic activity was detected.     

Alternative antiparasitic treatment of horses with pyrantel pamoate suspension and ivermectin oral solution compared with horses treated only with ivermectin

A practical parasite control program was evaluated in a 2-year clinical trial using pyrantel pamoate suspension (PYR) and ivermectin oral solution (IVM) in a seasonal rotation program, in comparison with continued use of IVM given at 2-month intervals. At least 15 horses in each of 2 treatment groups were distributed over 8 locations. In the alternation program, IVM was given twice (October, December) during the botfly (Gasterophilus spp.) season and again in April to treat against the lighter botfly season and to kill existing Onchocerca microfilariae prior to heavy Culicoides swarming. Pyrantel was given in February, June and August to continue suppression of strongyle infections and to treat against potentially developing Anoplocephala infections. In the program of IVM continuous use, the drug was given on the same schedule as either treatment on the alternation program.The course of strongyle infections was monitored by fecal sample analyses (EPG) at semimonthly intervals and by larval cultures of treatment pairs prepared at each treatment interval (alternation program) or at 4-month intervals (continuous IVM program). The strongyle egg count numbers were reduced to zero by the first IVM treatment, increased only slightly by the next treatment at 2 months, and repeated the reduced pattern with each treatment for 2 years. The alternation program in the first year had typical responses to each drug: IVM reducing strongyle EPG counts to zero which increased slightly at 2 months, followed by the PYR treatment, which reduced the strongyle egg counts for 4 weeks with rebound at 6 and 8 weeks. At the end of the first year and into the second, the IVM treatments of October and December established a zero or low strongyle EPG pattern which continued through the spring with PYR and IVM treatments. The second summer PYR treatments then maintained far better cyathostome control than had been reported for this drug. There may be a complementary or enhancing effect by prior treatment with ivermectin within the rotation protocol. The practical therapeutic compatibility between these 2 antiparasitics became obvious. Anoplocephala eggs were found in feces of some horses treated with IVM only, but no Anoplocephala eggs were found in post-treatment feces of horses treated on the alternation program.Strongyle larval cultures prepared as treatment pairs indicated high efficacy by ivermectin throughout the 2 years whether used alone or as a rotational drug, with improved cyathostome control by pyrantel pamoate. The combined use of EPG determinations and concurrent larval cultures in anthelmintic evaluations provide a greater spectrum of reliable results than from parasite egg counts alone.