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1.
J.R. Egerton E.S. Brokken D. Suhayda C.H. Eary J.W. Wooden R.L. Kilgore 《Veterinary parasitology》1981,8(1):83-88
Parenteral administration of ivermectin (22,23-dihydroavermectin B1) significantly reduced the numbers of adult large and small strongyles, the immature stages of small strongyles, pinworm and ascarid, the microfilariae of Onchocerca cervicalis and gastrophilid bots from naturally infected horses. Strongylus vulgaris, S. edentatus and S. equinus were effectively removed by 0.02 mg/kg. Adult small strongyles, Cyathostomum pateratum, C. catinatum, Cylicocyclus nassatus, C. leptostomus, Cyliostephanus minutus, C. longibursatus and C. goldi, were effectively removed by 0.1 mg/kg. Fourth stage small strongyles (cyathostomes), 4th stage Oxyuris equi, 5th stage Parascaris equorum and the microfilarie of Onchocerca cervicalis were significantly reduced by 0.1 mg/kg also. The stomach bots, Gastrophilus intestinalis and G. nasalis, were effectively removed by 0.02 mg of ivermectin/kg. Analysis of the dose response curves obtained for the nematode and larval dipteran parasites found in these naturally infected horses suggests that a parenteral dose of 0.2 mg/kg ivermectin would produce 95% or more removal of these parasites. The antiparasitic efficacies observed for ivermectin in this controlled trial were equivalent to the efficacies found in an abbreviated critical trial contained within the controlled trial. However, it was calculated that the man—day effort required for data collection from one critical trial horse was the same as for 6 controlled-trial horses. 相似文献
2.
Benzimidazole resistance of equine strongyles: critical tests of several classes of compounds against population B strongyles from 1977 to 1981 总被引：2，自引：0，他引：2
From 1977 to 1981, critical tests were conducted on 10 horses naturally infected with population B strongyles. Drugs tested were: oxibendazole (OBZ), 10 mg/kg of body weight (n = 1); albendazole, 10 mg/kg (n = 1); a mixture of thiabendazole (TBZ), 44 mg/kg and trichlorfon, 40 mg/kg (n = 1); a mixture of TBZ at 44 mg/kg with piperazine (PPZ) at 55 mg of base/kg (n = 1); febantel (FBT), 6 mg/kg (n = 3), 12 mg/kg (n = 1), or 24 mg/kg (n = 1); and pyrantel (PRT) pamoate, 6.6 mg of base/kg (n = 1). Large strongyles, Strongylus vulgaris (9 horses) and S edentatus (5 horses), were effectively removed (100%) by each compound and mixture. Five species of small strongyles (Cyathostomum catinatum, Cyathostomum coronatum, Cylicocyclus nassatus, Cylicostephanus goldi, and Cylicostephanus longibursatus), previously singled out in this population as resistant to 5 benzimidazoles (TBZ, mebendazole, cambendazole, fenbendazole, and oxfendazole), but not OBZ, were efficaciously removed by OBZ, albendazole, the mixture of TBZ plus PPZ, FBT (24 mg/kg), or PRT. These 5 small strongyle species were resistant to FBT (6 mg/kg) in 3 foals and Cylicostephanus minutus was also resistant in 2 of 3 foals to FBT (6 mg/kg). Doubling the dose of FBT to 12 mg/kg increased the average removal of the 5 basic species plus Cylicostephanus minutus to 88%. The mixture of TBZ and trichlorfon was relatively ineffective against 3 species (C catinatum, C coronatum, and Cylicostephanus longibursatus), but unexpectedly efficacious (86% to 99%) for 2 species (Cylicocyclus nassatus and Cylicostephanus goldi).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
3.
Benzimidazole resistance of equine stronygles--critical tests of six compounds against population B 总被引：1，自引：0，他引：1
Critical tests were conducted on eight horses naturally infected with several species of large and small strongyles from population B. Tested were six benzimidazoles, including thiabendazole (2 lots) (44 mg/kg of body weight); mebendazole (8.8 mg/kg); cambendazole (two formulations) (20 mg/kg); fenbendazole (10 mg/kg); oxibendazole (10 mg/kg); and oxfendazole (10 mg/kg). All compounds were administered by stomach tube except one of the two cambendazole formulations which was an intraoral paste. Removal of large strongyles (when present), Strongylus vulgaris and Strongylus edentatus, was 100% by each drug. In general, five species of small strongyles (Cyathostomum catinatum, Cyathostomum coronatum, Cylicocyclus nassatus, Cylicostephanus goldi, and Cylicostephanus longibursatus) exhibited varying degrees of resistance (% removal) to all of the drugs except oxibendazole. A total of 19 other species of small strongyles from seven genera, including the three described earlier were about 100% removed by the six benzimidazoles. Poor removal of immature (fourth-stage larvae) forms was also characteristic of the six drugs. 相似文献
4.
Seven critical tests in equids were conducted with single doses of fenbendazole (5 mg kg-1) alone (Panacur--American Hoechst, Somerville, NJ); (2 tests with paste and 1 with suspension formulation) or in combination with piperazine (American Hoechst); (40 mg base kg-1); (4 tests with paste formulation). The main purpose of the tests was evaluation of activity against benzimidazole-resistant small strongyles (Cyathostomum catinatum, Cyathostomum coronatum, Cylicocyclus nassatus, Cylicostephanus goldi, and Cylicostephanus longibursatus). Natural infections of 2 populations of benzimidazole-resistant small strongyles were evaluated; 1 was population B in 2 horses and the other was population S in 5 ponies. Removal of the 5 species of population B was 49-91% in the animal treated with fenbendazole paste alone and 100% (4 of these species present) in the animal treated with the combination. For population S, 2 of the 5 resistant species were present in small numbers in 1 animal treated with fenbendazole paste alone and all were removed; the 1 animal receiving fenbendazole suspension alone had removals of 0-70% for the 5 benzimidazole-resistant species. Also for population S, the 5 resistant species were present in 2 animals treated with the paste combination and removal was 98-100% and of 4 of the 5 resistant species in 1 animal, removal was 76-99%. Removal of large strongyles (Strongylus vulgaris and Strongylus edentatus) was 92-100% for fenbendazole paste alone or in combination with piperazine in the 5 infected animals. For Oxyuris equi, present in 1 animal treated with the combination, there was 91% removal of immature and 100% removal of mature specimens. There probHably was no activity by fenbendazole alone or the combination against bots, tapeworms, and parenteral stages of S. vulgaris and S. edentatus. The combination may have had some activity against immature Habronema spp. and mature abronema muscae. 相似文献
5.
The anthelmintic activity of cambendazole 31% paste was evaluated in a controlled trial against naturally acquired gastro-intestinal parasites of the horse. Four groups of five adult horses were treated at dose rates of 0, 15, 20 and 25 mg/kg. The three dose levels of cambendazole tested were efficacious against the large strongyles Strongylus edentatus and S. vulgaris, the stomach worm Trichostrongylus axei, the pinworms Oxyuris equi and Probstmayria vivipara and all the species of small strongyles present. No efficacy was demonstrated against the tapeworm Anoplocephala perfoliata or the horse bots Gasterophilus intestinalis or G. nasalis 相似文献
6.
Critical tests were completed on six horses to evaluate the antiparasitic activity of a paste formulation mixture of morantel citrate and trichlorfon, administered intraorally at the dose rate of 6 mg morantel base kg-1 and trichlorfon at 30 mg kg-1. Aggregate average removals were: 78% for two horses infected with 2nd instar Gasterophilus intestinalis; 100% for one infected with 2nd instar G. nasalis; 96% for six infected with 3rd instar G. intestinalis; 100% for four infected with 3rd instar G. nasalis; 100% for five infected with Parascaris equorum; 100% for one infected with mature Oxyuris equi; 100% for five infected with Strongylus vulgaris; 72% for five infected with S. edentatus; and partial removal (25%) of Anoplocephala perfoliata infection from one infected animal. Pre- and post-treatment EPG and LPG data indicated a reduction of 97% of the mature small strongyle infections. Evidence of toxicosis was not observed in any of the horses. 相似文献
7.
T R Bello 《American journal of veterinary research》1991,52(4):566-569
A controlled test was done in 30 naturally infected ponies to evaluate the antiparasitic activity of the dienbendazole analog VET 220-S given alone or with trichlorfon (TCF) by nasogastric intubation. Six ponies were nontreated; 6 were given VET 220-S (5.0 mg/kg); 6 were given TCF (40 mg/kg); 6 were given VET 220-S (2.5 mg/kg) and TCF (40 mg/kg); and 6 were given VET 220-S (5.0 mg/kg) and TCF (40 mg/kg). All ponies were euthanatized and necropsied 7 or 8 days after treatment. Draschia megastoma, Oxyuris equi, Strongylus vulgaris, S edentatus, and small strongyles were removed efficaciously by all doses of VET 220-S. Habronema muscae and microfilariae of Onchocerca cervicalis were not removed by VET 220-S or TCF. Gasterophilus intestinalis was 97.9% removed by TCF. Pregnant mares in all groups were not adversely affected by treatment, except for 1 mare that had diarrhea after TCF treatment. Parasite eggs per gram and larval culture data agreed with necropsy data. 相似文献
8.
Objective To compare the efficacy of moxidectin to ivermectin, oxibendazole and morantel against some gastrointestinal nematodes in horses.
Design Faecal egg count reduction after treatment.
Procedure A farm was selected where the population of small strongyles in horses was known to be resistant to oxibendazole. Horses were allocated to treatment groups based on faecal egg counts. After treatment, faecal samples were taken up to 109 days after treatment and faecal egg counts estimated. Faecal cultures were used to estimate the contribution of small and large strongyles to the faecal egg counts at each sampling.
Results Moxidectin (0.4 mg/kg) suppressed faecal egg counts for 109 days after treatment in most horses compared to 40 days with ivermectin (0.2 mg/kg), 13 days with morantel (9.4 mg/kg) and less than 13 days with oxibendazole (10 mg/kg). Most of the faecal egg count was attributable to small strongyles based on faecal culture, although Strongylus vulgaris was present in some samples in low numbers. Oxibendazole resistance in small strongyles was confirmed and a less than expected efficacy of morantel was also seen.
Conclusion Moxidectin was highly effective in reducing faecal egg counts after treatment for at least 12 weeks and up to 16 weeks in most horses. These horses were infected with a population of small strongyles known to be resistant to oxibendazole and possibly morantel. The duration of the reduction in faecal egg counts after treatment with moxidectin (0.4 mg/kg) was at least twice that of ivermectin (0.2 mg/kg) and greater than four times that for morantel and oxibendazole. 相似文献
Design Faecal egg count reduction after treatment.
Procedure A farm was selected where the population of small strongyles in horses was known to be resistant to oxibendazole. Horses were allocated to treatment groups based on faecal egg counts. After treatment, faecal samples were taken up to 109 days after treatment and faecal egg counts estimated. Faecal cultures were used to estimate the contribution of small and large strongyles to the faecal egg counts at each sampling.
Results Moxidectin (0.4 mg/kg) suppressed faecal egg counts for 109 days after treatment in most horses compared to 40 days with ivermectin (0.2 mg/kg), 13 days with morantel (9.4 mg/kg) and less than 13 days with oxibendazole (10 mg/kg). Most of the faecal egg count was attributable to small strongyles based on faecal culture, although Strongylus vulgaris was present in some samples in low numbers. Oxibendazole resistance in small strongyles was confirmed and a less than expected efficacy of morantel was also seen.
Conclusion Moxidectin was highly effective in reducing faecal egg counts after treatment for at least 12 weeks and up to 16 weeks in most horses. These horses were infected with a population of small strongyles known to be resistant to oxibendazole and possibly morantel. The duration of the reduction in faecal egg counts after treatment with moxidectin (0.4 mg/kg) was at least twice that of ivermectin (0.2 mg/kg) and greater than four times that for morantel and oxibendazole. 相似文献
9.
A paste formulation containing 14.3 per cent of oxibendazole and 44 per cent of trichlorfon was administered to 33 ponies and horses. The dose rate used was equivalent to 10 mg and 30 mg/kg bodyweight, of oxibendazole and trichlorfon respectively. After treatment 25 animals passed between one and 82 third stage larvae of Gasterophilus intestinalis in their faeces. Dosing with 0.2 mg ivermectin/kg bodyweight three weeks later resulted in six animals expelling between one and four bots. The efficacy of the oxibendazole-trichlorfon paste was on average 96.2 per cent. This drug combination given to 52 ponies and horses at the indicated dose rate and to six ponies at twice that dose was tolerated without side effects except transient softening of the faeces in several animals and mild symptoms of colic in two horses. 相似文献
10.
Critical tests were done on 24 naturally parasitized horses to compare the antiparasitic activity of an oral paste preparation of mebendazole and trichlorfon with that of the marketed powder formulation. Each formulation was administered at the recommended dosages of 8.8 mg of mebendazole and 40 mg of trichlorfon/kg of body weight. Efficacy of the paste formulation ranged from 97.7% to 100% against 2nd- and 3rd-stage Gasterophilus spp, adult Strongylus vulgaris, S edentatus, Parascaris equorum, small strongyles; and larval and adult forms of Oxyuris equi. Adverse effects were generally limited to slight softening of the feces. Mild and transient restlessness or sweating were also observed in 2 of 12 horses treated with the paste formulation. The toxic effects of the paste, administered at 2.2 times the therapeutic dose, were examined in 6 horses and compared with the effects of a nonmedicated paste, administered in similar volumes to 6 other horses. Drug-related changes were not detected in clinical chemical analyses, hematologic values, or liver function tests. Transient clinical signs of organophosphate toxicosis (primarily the passage of loose feces) and prolonged inhibition of erythrocyte cholinesterase activity were evident within 1 hour after drug treatment. These effects were similar to those reported for the 2.2 X dose of marketed powder formulation. 相似文献
11.
M L Colglazier 《American journal of veterinary research》1979,40(3):384-386
The efficacy of the benzimidazole, oxfendazole, and the organophosphate, caviphos, against gastrointestinal parasites of ponies was evaluated by the critcial test method. Oxfendazole (10 mg/kg of body weight) given in single oral doses was 100% effective against adult large strongylids (Strongylus vulgaris, Strongylus edentatus, and Strongylus equinus), 99% effective against adult small strongylids, and 97% effective against 4th-stage small strongylids (genera identified in order of frequency: Cylicostephanus, Cyathostomum, Cylicocyclus, Triodontophorus, Poteriostomum, Oesophagodontus, Cylicodontophorus, Gyalocephalus, and Craterostomum). Caviphos (40 mg/kg of body weight) admixed in the grain ration (horse crunch) was 89% effective against adult large strongylids (S vulgaris and S edentatus) and 99% effective against adult small strongylids (genera identified earlier in order of frequency above), but only 35% effective against 4th-stage small strongylids. Both drugs were effective (100%) against adult and immature pinworms (Oxyuris equi) but ineffective against Habronema spp and Draschia megastoma. Oxfendazole was only 11% effective against stomach bots (Gasterophilus spp); caviphos was 73% effective against these species. During a three-day pretreatment interval, about 34% of the total population of small strongylids was lost spontaneously from the 29 ponies. 相似文献
12.
Prevalence of internal parasites in horses in critical tests of activity of parasiticides over a 28-year period (1956-1983) in Kentucky 总被引：1，自引：0，他引：1
The prevalence and number of naturally acquired gastrointestinal parasites were compiled for horses used in critical tests of activity of parasiticides over a 28-year period (1956-1983). Data are presented as follows: n = number of horses examined; % = mean prevalence; number in parentheses after % = aggregate mean number of parasites in infected horses. Parasites found were: bots (n = 513) - Gasterophilus intestinalis, 2nd instar, 61%(58); 3rd instar, 94%(168); G. nasalis, 2nd instar, 36%(28); 3rd instar, 81%(51); stomach worms (n = 200) - Habronema muscae, 65%(179); Draschia megastoma, 29%(95); Trichostrongylus axei, 46%(3000); ascarids (n = 513) - Parascaris equorum, mature, 50%(25); immature, 23%(33); tapeworms (n = 513), Anoplocephala perfoliata, 17%(15); A. magna, 14%(10); large strongyles (n = 487), Strongylus vulgaris, 84%(80); S. edentatus, 79%(101); S. equinus, 6%(14); small strongyles (n = 210), 100%(142,000); pinworms (Oxyuris equi), immature (n = 210), 78%(9000); mature (n = 506), 40%(62); Probstmayria vivipara (n = 210), 12%(10(7]; S. vulgaris in cranial mesenteric artery (n = 472), 89%(57). The majority of the horses examined were mixed lighthorse type but several Thoroughbreds were included. Ages varied from about 4 months to 20 years old, with most being approximately 1-3 years old. They probably had either no or infrequent previous treatment with parasiticides. Most of the horses were selected for presence of certain internal parasites, usually large strongyles, prior to usage in the critical tests. 相似文献
13.
Thirteen critical tests (n = 11 horses and 2 ponies) and 4 controlled tests (n = 4 donkeys and 6 horses) were performed to evaluate the activity of the experimental macrocyclic lactone compound F28249-alpha against internal parasites of equids. In the critical tests, activity was determined mainly against the large parasites, but 1 critical test also included benzimidazole-resistant small strongyles. In the controlled tests, evaluation of drug activity included large parasites and stomach worms in all 4 tests, and lungworms in 2 tests. The period between treatment and euthanasia was 6 to 9 days for the critical tests and 14, 17, or 52 days for the controlled tests. The compound was administered by stomach tube at dose rates of 1, 2, 3, 3.5, or 4 mg/kg of body weight. In the critical tests, removal at all 5 dose rates was 100% for Gasterophilus nasalis (2nd and 3rd instars), Parascaris equorum (mature), Strongylus vulgaris, and Strongulus edentatus from the gastrointestinal tract. For Gasterophilus intestinalis in the stomach, mean removals of 2nd instars were 88% at the rate of 2 mg/kg and 93% to 100% at rates greater than or equal to 3 mg/kg. For 3rd instars, mean removals were 7% at 1 mg/kg, 77% at 2 mg/kg, 90% at 3 mg/kg, and 98% at 3.5 mg/kg. Discharge of G intestinalis in feces was typically a slow, prolonged process and probably higher removal values, especially at lower dose rates, would have attended a longer interval after treatment before necropsy examination.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
14.
T R Bello 《American journal of veterinary research》1989,50(11):1976-1980
A controlled test was performed to titrate the anthelmintic dosage of dienbendazole in 24 mixed-breed ponies naturally infected with Strongylus vulgaris, S edentatus, and small strongyle species, as determined by parasitic egg and larval counts in feces. Comparison of results of treatment was made among 3 dienbendazole dosages--2.5, 5, and 10 mg/kg of body weight--and a gum (excipient) mixture given by nasogastric intubation. All ponies were euthanatized and necropsied at 7 or 8 days after treatment. Trichostrongylus axei, Habronema muscae, S vulgaris, S edentatus, small strongyles, and Oxyuris equi were efficaciously eliminated in response to all doses of dienbendazole; Gasterophilus spp were not affected by any dose. There were not sufficient numbers of Draschia megastoma, Anoplocephala spp, or Parascaris equorum in the ponies to evaluate drug effect. Changes in the appearance of the intestinal lining were dose-dependent; in the ponies treated with 5 and 10 mg of dienbendazole/kg, the mucosa appeared clean and smooth, though in ponies given 2.5 mg/kg, it appeared clean, but was nodular and moderately reactive to embedded immature small strongyles. In the gum mixture-treated ponies, the large intestinal mucosa was inflamed, with edematous areas, in response to infections caused by large and small strongyles. A limited clinical titration was done in 12 ponies that were fecal culture negative for S vulgaris larvae, although other strongyles were detected. Two ponies in each of 6 groups were given the following dosages: 0 (gum mixture only), 0.5, 1, 2.5, and 5 mg of dienbendazole/kg. One group of 2 ponies was given 5 mg of fenbendazole/kg as a standard treatment control.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
15.
The efficacy of fenbendazole against immature stages of Trichonema spp., Strongylus vulgaris and Strongylus edentatus was evaluated. Naturally infected 6 to 12 month old ponies were given single, oral doses of 0, 15, 30 and 60 mg/kg of body weight. A dose response relationship was noted between increasing dose levels and efficiency against larval trichonemes and migrating stages of S. vulgaris and S. edentatus. Dose levels of 30 mg/kg and higher removed 93 per cent of mucosal stages of Trichonema spp., while doses of 60 mg/kg removed 83 per cent and 89 per cent of the migrating larvae of S. vulgaris and S. edentatus respectively. 相似文献
16.
In order to assess the resistance situation against macrocyclic lactones in Parascaris equorum and against tetrahydropyrimidine derivatives in strongyles in Finnish trotter horses, 112 foals on 18 farms, mostly 1 year old, were examined for these parasites with a modified McMaster faecal flotation method. P. equorum positive foals (n=24) were given ivermectin orally at a dose of 200 μg/kg b.w., while strongyle positive but P. equorum negative foals (n=38) received pyrantel embonate orally at a dose of 19 mg/kg. Sixteen P. equorum infected foals, treated with ivermectin, also harboured strongyles. During the anthelmintic treatment visit to the farm, Faecal Egg Count Reduction Test (FECRT) reference (first) samples were collected. Fourteen days later, the second sampling (reduction samples) was done. The FECR was calculated for each foal/parasite combination. The reduction efficacies of ivermectin against P. equorum (mean 52%, calculated from the individual egg count reductions) and pyrantel against strongyles (43%) were strongly indicative of widespread resistance. Also indication of ivermectin resistance among strongyles was seen. The widespread use of anthelmintics for Finnish horses obviously has resulted in resistance, as has happened elsewhere, too. 相似文献
17.
In a controlled trial in naturally-infected young ponies, oxfendazole administered orally at dose-rates of 10 mg per kg and 50 mg per kg resulted in complete elimination of Trichostrongylus axei, Parascaris equorum, Oxyuris equi and adult Strongylus vulgaris. Also, all migrating Strongylus edentatus larvae recovered from the subperitoneal tissues of the flank were found to be dead. Minimum efficiencies of 99.8 per cent and 99.1 per cent were obtained against adult small strongyles (Trichonema spp) and 97.6 per cent and 100 per cent of developing small strongyle larvae at dose-rates of 10 mg per kg and 50 mg per kg respectively. Although the arterial lesions caused by migrating S vulgaris larvae were less severe in the treated compared with the untreated animals, reductions in mean larval numbers over controls were only in the region of 49 to 59 per cent. 相似文献
18.
Phenothiazine in the origin of benzimidazole resistance in population-B equine strongyles 总被引：1，自引：0，他引：1
Clinical trials on a central Kentucky Thoroughbred Farm (B) during 1960-1961 involved nine test treatments of mares, yearlings and weanlings (n = 124), and compared efficacies of phenothiazine (PTZ), piperazine (PPZ), mixtures of PTZ + PPZ and thiabendazole (TBZ) for (1) percent reduction and (2) complete clearance or graded reduction of strongyle egg per gram (epg) counts. Three grades of PTZ (N.F. green, micronized purified and 2-3 microns purified) at the dose rate of 55 mg kg-1 were ineffective in six tests; reduction of strongyle epg count were low grade (26%) and complete clearance was found in only 1 of 32 horses. Piperazine alone at 88 mg base kg-1 was efficacious in two tests; epg counts were effectively reduced (98%), but complete clearance was found in only 2 of 10 horses. Several mixtures of PTZ + PPZ with various dosages of PTZ (27.5-55 mg kg-1) plus PPZ base (88 mg kg-1) were quite effective in six tests, as epg counts were reduced by 96% and complete clearance occurred in 25 of 38 horses. Four trials with TBZ at dose rates between 13 and 44 mg kg-1 in 1961 reduced epg counts by 98%, but cleared only 15 of 36 horses. These data indicated: (1) a large segment of the Farm B small strongyle population was resistant to PTZ at the outset of these observations in 1960; (2) TBZ-resistant individuals were also present in this population when TBZ was first used in 1961. During the ensuing 4-year study (1962-1965) on Farm B mares (n = 15 per year) and yearlings (n = 15-17 per year), biweekly epg and larvae per gram (lpg) counts were carried out to compare the efficacy of three treatment programs: (1) monthly doses of TBZ at 26 mg kg-1; (2) monthly doses of TBZ at 13 mg kg-1; (3) bimonthly doses of a mixture of PTZ + PPZ and carbon disulfide (CS2) at dose rates of 27.5 + 88 and 78 mg kg-1, respectively, or a mixture of PTZ + PPZ + trichlorfon (TCF) at dose rates of 27.5 + 88 + 40 mg kg-1, respectively. Emergence of a TBZ-resistant segment of the small strongyle infections was evaluated by three criteria: (1) annual mean strongyle epg counts; (2) efficacy of individual treatments for epg reductions (%); (3) complete clearance or graded reductions of strongyle epg counts.4+ PTZ-resistant small strongyles. Initial use of TBZ in 1961 produced effective epg reductions, but complete clearance data revealed the presence of TBZ-resistant small strongyles at the outset... 相似文献
19.
Interactions between treatments with coumaphos, bishydroxycoumarin (an anticoagulane), trichlorfon (an organophosphorous compound), and phenobarbital sodium (an inducer of microsomal enzymes) were investigated in sheep. A daily dose of 2 mg of coumaphos/kg of body weight for 6 days did not affect the plasma enzymes or the antiprothrombinemic effect of bishydroxy-coumarin in wethers. The treatment of ewes with an intravenous (IV) injection of trichlorfon, insufficient to produce significant inhibition of erythrocyte acetylcholinesterase (AChE) activity, appeared to produce additive effects with those produced by subsequent treatment with 4 mg of coumaphos/kg/day. In ewes given 40 mg of phenobarbital sodium/kg for 5 days intraperitoneally (IP), the anticholinesterase effect of 4 mg of coumaphos/kg was significantly reduced and signs of toxicity were not present. Treatment with daily doses of 2 mg of coumaphos/kg for 6 days did not modify the anticholinesterase effect of a 2nd series of treatments given 6 weeks later. 相似文献
20.
The efficacy of ivermectin, fenbendazole, pyrantel pamoate and doramectin was evaluated under field conditions at 2 sites in the Free State Province of South Africa. The study involved 25 horses at each site, divided into 5 groups of equal size. Ivermectin, fenbendazole and pyrantel pamoate were administered orally at doses of 0.2, 10 and 19 mg/kg respectively. Doramectin was administered by intramuscular injection at a dose of 0.2 mg/kg. Treatment efficacy was based on the mean faecal egg count reduction 14 days post treatment. At site A a faecal egg count reduction of 100% was found after treatment with ivermectin, fenbendazole and doramectin. A 96.1% reduction was found after treatment with pyrantel pamoate. At site B ivermectin and doramectin produced a 100% reduction in faecal egg counts, fenbendazole produced an 80.8% reduction and pyrantel pamoate a 94.1% reduction. Doramectin produced a 100% reduction in faecal egg counts at both sites, despite not being registered for use in horses. In addition, the results indicated reduced efficacy of fenbendazole at site B, which suggested benzimidazole resistance. Larval cultures showed that cyathostomes accounted for between 86 and 96% of pre-treatment parasite burdens at both sites. Other helminths identified in the faecal samples were Strongylus spp. and Trichostrongylus axei. 相似文献