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1.
Comparative long-term efficacy of ivermectin and moxidectin over winter in Canadian horses treated at removal from pastures for winter housing 
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下载免费PDF全文 Johanne Elsener Alain Villeneuve 《The Canadian veterinary journal. La revue veterinaire canadienne》2009,50(5):486-490
The impact of a late fall treatment on the spring rise of fecal egg counts was evaluated in a controlled study with Canadian horses treated with 2 different dewormers immediately after removal from pasture for winter housing. The horses were stabled until the end of the trial period. Seventeen weanlings, 20 yearlings, and 15 2-year-old horses located in Ontario, which were presumed to be naturally infected with cyathostomins after pasture grazing, were randomly allocated to either a group treated with 0.4 mg/kg of moxidectin and 2.5 mg/kg of praziquantel or a group treated with 0.2 mg/kg of ivermectin and 1.5 mg/kg of praziquantel. Three weeks after treatment, all strongyle fecal egg counts were reduced to zero for both treatment groups. However, at 5 months post-treatment, mean geometric fecal egg counts were statistically higher for the yearlings and 2-year-old horses treated with ivermectin than for the yearlings and 2-year-old horses treated with moxidectin (P < 0.0001). 相似文献
2.
Eighty horses were involved in a comparative, controlled, and randomised field study conducted in Australia and Brazil. This study was undertaken to address the duration of efficacy (by faecal egg count reduction) of four anthelmintic pastes and to measure the time required between treatments on horses naturally infected by gastrointestinal nematodes. The treatment interval was based on the egg reappearance period (ERP), defined as "the period after treatment when horses have reached a positive egg count equal or superior to 200 eggs per gram (epg) of faeces". Horses were ranked according to pre-treatment faecal egg counts and randomly allocated on Day 0 to one of the four treatment groups (n=16). Group A received a combination of ivermectin at 200 microg/kg and praziquantel at 1.5mg/kg, Group B received an ivermectin paste at 200 microg/kg, Group C received a reference product containing ivermectin at 200 microg/kg, Group D received a moxidectin paste at 400 microg/kg, and Group E received a placebo. Horses were individually faecal sampled at weekly interval from Days 0 to 70 after treatment and coprocultures were made on pooled samples at the pre-treatment time on D-7 in Brazil and D-6 in Australia.The nematode population was mainly composed of small strongyles (Cyathostominae, Gyalocephalus spp., Triodontophorus spp.). All products were efficient (>90% efficacy) until Day 42 with no statistical difference between groups. From Day 49 onwards, Group C reached the threshold, while Group B exceeded this threshold on Day 56. Groups A and D remained below 200 epg for the entire study period (70 days). The interval between two anthelmintic treatments can vary according to the threshold. The ERP was defined as the period after treatment while the output of eggs is negligible or considered as acceptable. The mean number of days calculated to recurrence of 200 epg and more was, respectively, 60 days for product A, 56 days for products B and C, and 64 days for product D. If treatments are combined with other methods of limiting exposure to infective larvae on pasture, the number of treatments required will be reduced even further. 相似文献
3.
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
4.
Grubbs ST Amodie D Rulli D Wulster-Radcliffe M Reinemeyer C Yazwinski T Tucker C Hutchens D Smith L Patterson D 《Veterinary therapeutics : research in applied veterinary medicine》2003,4(3):249-256
The safety and efficacy of 2% moxidectin/12.5% praziquantel oral gel administered at a rate of 0.4 mg moxidectin and 2.5 mg praziquantel/kg was studied in client-owned horses under field use conditions. Four hundred horses (300 treated with moxidectin/praziquantel oral gel and 100 treated with vehicle) were enrolled, feces were collected, and eggs were counted. Investigators as well as horse owners were masked to treatment assignment. No adverse reactions to treatment were observed in any horses. Moxidectin/praziquantel gel reduced Anoplocephala spp by more than 99% and provided a significant (P <.05) reduction (> 98%) in the strongyle egg count of treated horses. 相似文献
5.
Equine helminth infections: control by selective chemotherapy 总被引：3，自引：0，他引：3
A programme of selective anthelmintic therapy was used in a herd of 31 horses. Faecal egg counts were done during the months of September, November, January, March, May and the following September. Horses with greater than or equal to 100 eggs per gram (epg) were treated with ivermectin, and those with less than 100 epg were not treated. The criteria for adequate internal parasite control in the herd was a median herd faecal egg count of less than or equal to 100 epg. Effectiveness of selective therapy was assessed by faecal egg count after nine months of treatment and was determined to be adequate when a median herd egg count of 0 epg was obtained. However, on returning from pasture the following September, median herd egg count had risen to 325 epg. A statistically significant correlation was seen in the paired September faecal egg counts of the horses in that initial September faecal egg count was predictive for the following September. Initial September faecal egg count was related to the number of anthelmintic treatments required during the period of selective therapy, whereas age of horse was not. We propose that faecal egg counts be incorporated into strategic anthelmintic programmes as an economical tool for identifying and targeting herd members predisposed to shedding elevated numbers of helminth eggs. 相似文献
6.
Two hundred and thirty-three horses were screened for the presence of roundworms by faecal egg counts (FECs) and for tapeworms by an ELISA specific for antibodies to the immunodominant 12 kDa and 13 kDa tapeworms antigen. The 62 horses were found to be infected with both parasites were treated with a combination of 0.2 mg/kg ivermectin and 1.5 mg/kg praziquantel. The treatment suppressed the median FEC of the horses to zero for 10 weeks and significantly reduced their anti-12/13 kDa antibody levels. The estimated risk of tapeworm-associated colic in these horses was halved by 12 weeks after the treatment. 相似文献
7.
Brazik EL Luquire JT Little D 《Journal of the American Veterinary Medical Association》2006,228(1):101-103
CASE DESCRIPTIONS: 16 horses treated daily with pyrantel tartrate (2.64 mg/kg [1.2 mg/lb], PO) as part of a prophylactic anthelmintic program. CLINICAL FINDINGS: Fecal worm egg counts (FWECs) were obtained on all 16 horses. Mean FWEC was 478 eggs/g (epg; range, 0 to 4,075 epg). Three of the 16 horses were responsible for 85% of the total fecal egg output for the herd on the day of sampling. Six horses had FWECs < 200 epg. Three horses that had arrived within 4 months of the sampling date had FWECs < 100 epg. TREATMENT AND OUTCOME: An FWEC reduction test was initiated the day after FWECs were obtained; all horses with FWECs > 100 epg (9 horses) were treated with pyrantel pamoate (6.6 mg/kg [3 mg/lb], PO), and 14 days later, the FWEC was repeated. During the 14-day period, all horses received pyrantel tartrate (2.64 mg/kg, PO) daily. Fecal worm egg count reduction was calculated for each horse. Mean FWEC reduction for the group was 28.5% (range, increase of 21% in FWECs 14 days after treatment to a decrease of 100% in FWEC 14 days after treatment). CLINICAL RELEVANCE: Farms should be monitored for cyathostomes resistant to pyrantel pamoate prior to use of pyrantel tartrate. Fecal worm egg counts should be monitored routinely in horses before and after treatment to ensure efficacy of cyathostome control measures. 相似文献
8.
Studies on a Thoroughbred breeding farm in Ohio from 1982 to 1988 demonstrated the value of three anthelmintic pastes (ivermectin, oxibendazole, pyrantel pamoate) in controlling benzimidazole resistant cyathostomes (small strongyles) in adult horses. However, a comparison of drug efficacy in suppressing faecal egg counts for the full period between treatments showed a significant reduction in efficacy of all drugs in yearling horses compared with adults. Mean faecal egg counts of adult horses were generally kept below 100 eggs per gram (epg) of faeces when using oxibendazole or pyrantel pamoate at four to five week intervals and ivermectin at eight week intervals. By contrast, mean counts of young horses rose as high as 655 epg (oxibendazole), 729 epg (pyrantel pamoate) and 852 epg (ivermectin) within the same time period after treatment. Individual counts of treated yearlings sometimes exceeded 3,000 epg. Three distinct mechanisms appeared to be involved in the poor results in young horses. These were 1) anthelmintic refuge, 2) anthelmintic resistance, and 3) anthelmintic avoidance. 相似文献
9.
Matthee S 《Journal of the South African Veterinary Association》2003,74(2):53-56
Anthelmintic products form the basis of helminth control practices on horse stud farms at present. Regular evaluation of the efficacy of these products is advisable, as it will provide information on the worm egg reappearance period and the resistance status in the worm population. The aim of this study was to evaluate the efficacy of doramectin, pyrantel pamoate, ivermectin and moxidectin on a Thoroughbred stud farm in the Western Cape Province, South Africa. The study also compared the anthelmintic efficacy of two moxidectin formulations administered at their recommended dosages (an injectable, at 0.2 mg/kg, not registered for horses, and an oral gel at 0.4 mg/kg, registered for horses). Two mixed-sex groups of 30 yearlings and 40 weaners were tested in 2001 and 2002, respectively, divided into 3 and 4 groups of equal size. In 2001, moxidectin was one of 3 drugs administered orally and at a dose rate of 0.4 mg/kg. In 2002, pyrantel pamoate and ivermectin were orally administered at 19 and 0.2 mg/kg. Moxidectin and doramectin (the latter not registered for horses) were administered by intramuscular injection at a dose of 0.2 mg/kg, the dosage registered for other host species. The faecal egg count reduction test was used to determine the anthelmintic efficacies in both years. Each animal acted as its own control and the arithmetic mean faecal egg count and lower 95% confidence limit was calculated for each of the groups. A 100% reduction in the faecal egg counts and a 100% lower 95% confidence limit was recorded for moxidectin (0.4 mg/kg) in 2001. In 2002, a 99% and 96% reduction was recorded for pyrantel pamoate and ivermectin, respectively. In the same year doramectin and moxidectin (both injectable and given at 0.2 mg/kg) did not have any effect on worm egg counts. Of the 4 drugs tested in 2002, only pyrantel pamoate recorded lower 95% confidence limits above 90%. 相似文献
10.
Effectiveness of oxibendazole against benzimidazole-resistant strongyles in horses 总被引：1，自引：1，他引：0 下载免费PDF全文
下载免费PDF全文 Slocombe JO Cote JF McMillan I 《The Canadian veterinary journal. La revue veterinaire canadienne》1989,30(8):663-665
Twenty-eight horses with a residual burden of strongyle eggs in the faces after treatment with mebendazole (MBZ) paste were treated with a suspension of either MBZ or oxibendazole (OBZ). Fecal samples were collected before and 14 days after these treatments. The number of strongyle eggs/g (epg) of feces for each horse was estimated using the Cornell-McMaster dilution and the Cornell-Wisconsin double centrifugation procedures. The epg for each horse was transformed using log (× + 1) and in an analysis of variance of the reduction in egg count for each horse on the logarithmic scale, there was a highly significant difference between the treatments. The mean epg was increased in the MBZ-treated horses and reduced in the OBZ-treated horses, but the reduction was only by 82% with an upper confidence limit of 89%. Subsequently, the horses were retreated with MBZ and OBZ suspensions without significant reduction in the mean epg for OBZ-treated horses. 相似文献
11.
J A DiPietro K S Todd T F Lock V Reuter-Dallman 《Journal of the American Veterinary Medical Association》1985,186(3):262-264
Fifty horses from a herd known to have benzimidazole-resistant small strongyles were treated with febantel (6 mg/kg), combinations of febantel (6 mg/kg) and piperazine citrate (25 or 55 mg base/kg), thiabendazole (44 mg/kg), or placebo (0.6 ml of water/kg). Pretreatment and 7-day posttreatment fecal examinations were done. Fecal cultures, strongyle egg per gram (epg) counts, sugar flotation fecal examinations, and in vitro testing for benzimidazole resistance were performed. Results of fecal examinations before treatment were similar in all horses, and results of testing were positive for benzimidazole resistance. Horses treated with febantel and piperazine at all dosages had significantly lower mean strongyle epg counts and greater percentage reduction in mean strongyle epg counts (99.7% to 99.9%) 7 days after treatment, compared with those determined for horses treated with febantel, thiabendazole, or placebo. Adverse reactions to treatment were not observed. 相似文献
12.
Irvine RJ 《The Veterinary record》2000,147(20):570-573
An experiment was conducted to evaluate moxidectin as a tool for understanding the impact of parasitism on wild Svalbard reindeer (Rangifer tarandus platyrhynchus). Adult females were injected subcutaneously with moxidectin at a dose rate of 0-4 mg/kg bodyweight, and groups of animals were culled within its expected period of efficacy (around 14 days) or around 12 or 24 weeks after treatment. Moxidectin was effective in eliminating the reindeers' abomasal worm burdens, and although they became reinfected, worm burdens were significantly lower in the treated animals compared to the untreated controls for up to 24 weeks after treatment. Nematode eggs did not reappear in faeces until five weeks after treatment, a similar period to that claimed by the manufacturer for sheep and cattle. Animals culled 12 and 24 weeks after treatment had been reinfected and harboured a wide range of abomasal worm burdens which contributed to the understanding of the seasonal variation in the relationship between faecal egg count and worm burden. 相似文献
13.
Moxidectin has broad‐spectrum anti‐nematodal and anti‐arthropodal activities in the horse but is not effective against tapeworms or flukes. Moxidectin and ivermectin have the same efficacy against internal, adult parasites of horses. Moxidectin, however, is highly effective in eliminating encysted and hypobiotic larval stages of cyathostomins, whereas ivermectin is not. Treatment of horses with moxidectin results in an egg‐reappearance period (ERP) of 15–24 weeks. Because of its long ERP, moxidectin is labelled to be used at 12 week intervals. Moxidectin may provide protection against infection by ingested cyathostomin larvae for 2–3 weeks after it is administered. The larvicidal activity of moxidectin has often been compared to that of fenbendazole administered at either 7.5 or 10 mg/kg bwt for 5 consecutive days. The efficacy of fenbendazole, when administered daily for 5 consecutive days at 7.5 or 10 mg/kg bwt, against all stages of cyathostomins is often less than that of moxidectin because resistance of cyathostomins to benzimidazoles is prevalent worldwide, and the 5 day course of fenbendazole does not overcome this resistance. There are now reports of resistance of ascarids to moxidectin. Overt resistance of cyathostomins and a shortened egg re‐emergence period after treatment with moxidectin have been reported. Rapid removal of manure by natural fauna can significantly reduce larval nematode concentrations and thereby reduce intervals of anthelmintic treatment. Of the macrocyclic lactones, moxidectin has the least deleterious effect on faecal fauna. 相似文献
14.
The results from routine monitoring of parasite burdens in ewe flocks from 1980 to 1991 by the Massey University Veterinary Clinic were analysed. Faecal strongylate nematode egg counts from 401 flock samples were analysed according to ewe age (two-tooth, 16-23 month-old vs mixed-age, greater than 2-year-old ewes) and month of the year. Each flock sample contained faeces from ten ewes and nematode egg counts were carried out on each faecal sample. ln the mixed-age ewes, the overall mean faecal egg count per gram of faeces (epg) was lowest during January (82 epg) and rose to a peak during October (539 epg). The overall mean faecal egg count in two-tooth ewes remained constant from January (240 epg) to June (294 epg) and dropped during July (156 epg). Overall, 8% of the mixed-age ewes and 12% of the two-tooth ewe submissions had a mean egg count equal to or greater than 500 epg. It is possible that these data over-estimate the pasture contamination by ewes as farmers are more likely to submit faecal samples and to seek veterinary assistance when parasitism is thought to be a problem. The role of ewes as a source of pasture contamination should be considered when developing parasite control regimes on farms. 相似文献
15.
Faecal excretion profile of moxidectin and ivermectin after oral administration in horses 总被引：2，自引：0，他引：2
Pérez R Cabezas I Sutra JF Galtier P Alvinerie M 《Veterinary journal (London, England : 1997)》2001,161(1):85-92
A study was undertaken to evaluate and compare faecal excretion of moxidectin and ivermectin in horses after oral administration of commercially available preparations. Ten clinically healthy adult horses, weighing 390-446 kg body weight (b.w.), were allocated to two experimental groups. Group I was treated with an oral gel formulation of moxidectin at the manufacturer's recommended therapeutic dose of 0.4 mg/kg b.w. Group II was treated with an oral paste formulation of ivermectin at the recommended dose of 0.2 mg/kg b.w. Faecal samples were collected at different times between 1 and 75 days post-treatment. After faecal drug extraction and derivatization, samples were analysed by High Performance Liquid Chromatography using fluorescence detection and computerized kinetic analysis.For both drugs the maximum concentration level was reached at 2.5 days post administration. The ivermectin treatment groups' faecal concentrations remained above the detectable level for 40 days (0.6 +/- 0.3 ng/g), whereas the moxidectin treatment group remained above the detectable level for 75 days (4.3 +/- 2.8 ng/g). Ivermectin presented a faster elimination rate than moxidectin, reaching 90% of the total drug excreted in faeces at four days post-treatment, whereas moxidectin reached similar levels at eight days post-treatment. No significant differences were observed for the values of maximum faecal concentration (C(max)) and time of C(max)(T(max)) between both groups of horses, demonstrating similar patterns of drug transference from plasma to the gastrointestinal tract. The values of the area under the faecal concentration time curve were slightly higher in the moxidectin treatment group (7104 +/- 2277 ng.day/g) but were not significantly different from those obtained in the ivermectin treatment group (5642 +/- 1122 ng.day/g). The results demonstrate that although a 100% higher dose level of moxidectin was used, attaining higher plasma concentration levels and more prolonged excretion and gut secretion than ivermectin, the concentration in faeces only represented 44.3+/- 18.0% of the total parental drug administered compared to 74.3 +/- 20.2% for ivermectin. This suggests a higher level of metabolization for moxidectin in the horse. 相似文献
16.
REASONS FOR PERFORMING STUDY: Possible anthelmintic resistance on a breeding farm where a rapid rotation anthelmintic programme had been implemented for 9 years was investigated. Cyathostomins resistant to fenbendazole and pyrantel were documented by faecal worm egg count reduction test (FWECRT). OBJECTIVES: To 1) manage small strongyle transmission in a herd of horses in which resistance to both pyrantel pamoate and fenbendazole was identified and thereby reduce the risk of clinical disease in the individual animal, 2) monitor the change in resistance patterns over time and 3) monitor the efficacy of ivermectin over the study period. METHODS: Targeted ivermectin treatment of horses on the farm was instituted for mature horses with faecal worm egg counts (FWEC) > 200 eggs/g (epg) and for horses < age 2 years with FWEC > 100 epg. RESULTS: Over a 30 month period, targeted ivermectin treatment achieved acceptable control in mares, as judged by FWEC, and improved control of patent cyathostome infection in consecutive foal crops. Egg reappearance time (ERT) after treatment with ivermectin was < 8 weeks in mares and foals more frequently in the second year of the study than in the first year. Numbers of anthelmintic treatments were reduced by 77.6 and 533% in the mare and foal group, respectively. CONCLUSIONS: Targeted ivermectin treatment may be an economically viable method of managing multiple drug resistant cyathostominosis. POTENTIAL RELEVANCE: Use of ivermectin should be monitored closely for development of resistance. 相似文献
17.
Slocombe JO Coté JF de Gannes RV 《The Canadian veterinary journal. La revue veterinaire canadienne》2008,49(1):56-60
Three clinical trials with fecal egg count reduction tests and coproculture were conducted on 2 standardbred farms in Ontario. On Farm A, the treatment groups were mebendazole and ivermectin in trial 1, and fenbendazole and moxidectin in another. On Farm B, treatment groups were mebendazole and ivermectin. All horses treated with mebendazole or fenbendazole were subsequently treated with ivermectin or moxidectin. Strongyle eggs/g feces were estimated pre- and post-treatment using the Cornell-McMaster dilution and Cornell-Wisconsin centrifugal flotation techniques. After treatment, there was no change in the arithmetic mean eggs/g feces for horses given mebendazole, and a reduction of only 49.1% for those given fenbendazole. All horses receiving ivermectin or moxidectin had their egg counts reduced to 0. Only cyathostomes were found on culture. On both farms the benzimidazole resistant strains appeared to have persisted for at least 10 years. Development of and monitoring for anthelmintic resistance are briefly discussed. 相似文献
18.
AbstractAIM: To evaluate resistance to anthelmintics containing abamectin, levamisole, and oxfendazole (AB-LEV-OX), derquantal and abamectin (DEQ-AB), moxidectin, and monepantel in naturally acquired gastrointestinal nematodes present on a sheep farm.METHODS: Faecal nematode egg count reduction tests (FECRT) were carried out on lambs that were approximately 7 months-old and infected with naturally acquired nematodes. Lambs were randomly allocated to one of five groups (n=15 per group): treatment with 2?mg/kg derquantel and 0.2?mg/kg abamectin; 0.2?mg/kg abamectin, 8?mg/kg levamisole HCl and 4.5?mg/kg oxfendazole; 2.5?mg/kg monepantel; 0.2?mg/kg moxidectin, or no treatment. Post-treatment samples were collected 12 days later. Abomasa and small intestines were collected from two slaughtered lambs from each of the DEQ-AB, AB-LEV-OX, moxidectin and control groups 15 days after treatment, for nematode counting.RESULTS: The FECRT demonstrated that efficacy was 90.3 (95% CI=84.2–94.1)% for AB-LEV-OX, 54.5 (95% CI=28.4–71.1)% for moxidectin, 99.2 (95% CI=97.4–99.8)% for DEQ-AB and 100% for monepantel, across all genera. For Trichostrongylus spp. efficacy was 85.5% for AB-LEV-OX and 46.7% for moxidectin. Haemonchus spp. were fully susceptible to all treatments. Post-treatment nematode counts indicated that the resistant Trichostrongylus spp. were from the small intestine.CONCLUSIONS: Anthelmintic resistance to both AB-LEV-OX and moxidectin was present in the Trichostrongylus genus on a commercial sheep farm. Monepantel and DEQ-AB were both effective against Trichostrongylus spp. based on FECRT results.CLINICAL RELEVANCE: This finding of resistance to an AB-LEV-OX triple-combination anthelmintic in the Trichostrongylus genus in sheep in New Zealand further limits anthelmintic treatment options available, and calls into question whether this combination is suitable for use as a quarantine treatment. 相似文献
19.
Spickett A de Villiers JF Boomker J Githiori JB Medley GF Stenson MO Waller PJ Calitz FJ Vatta AF 《Veterinary parasitology》2012,184(1):48-58
Haemonchosis is considered to be the most economically important gastrointestinal disease of small ruminants in the tropics and subtropics. However, chemical anthelmintics, which were the mainstay of control, have been compromised by a high prevalence of resistance worldwide. Copper oxide wire particles (COWP) have been shown to have anthelmintic effects, but few studies have examined their use under field conditions. The use of COWP was therefore evaluated as a tactical anthelmintic treatment in indigenous goats raised under communal farming conditions in Bergville, KwaZulu-Natal Province, South Africa. At the beginning of the summer rainfall season (October 2007), the faecal egg counts of 172 female goats belonging to 15 farmers were determined and this sampling continued every four weeks until the second week of January 2008. The goats within each of the 15 herds were ranked according to their faecal egg counts for this week. The goats were sequentially paired off within each ranking starting with those goats with the highest counts. One goat from each pair was randomly allocated to a treated or control group. Two weeks later, a 4 g COWP bolus was randomly administered to each goat in the treated group. Faecal egg counts were carried out on the goats two weeks following treatment, and the sampling of the goats then proceeded every four weeks until October 2008. Except for the six-week period prior to the administration of the COWP, the goats were examined according to the FAMACHA© system and symptomatically treated with 12 mg/kg levamisole when anaemic. The percentage reduction in faecal egg count due to the COWP treatment was 89.0%. Mean pre- and post-treatment faecal egg counts for the COWP-treated group (n = 73) were 2347 eggs per gram of faeces (epg) and 264 epg, respectively. The corresponding values for the untreated controls (n = 66) were 2652 epg and 2709 epg. The prevalence of Haemonchus spp. larvae in pre- and post-treatment faecal cultures was 72% and 46%, respectively. Symptomatic anthelmintic treatments in combination with mid-summer tactical treatments with COWP appear to be useful strategies for the control of Haemonchus contortus in indigenous goats in this farming system and this approach could have application in other similar agro-ecological zones. 相似文献
20.
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. 相似文献