101
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Herd RP, Coles GC. Slowing the spread of anthelmintic resistant nematodes of horses in the United Kingdom. Vet Rec 1995; 136:481-5. [PMID: 7645183 DOI: 10.1136/vr.136.19.481] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The growing importance of anthelmintic resistance in cyathostomes (small strongyles) of horses poses a threat to the health and welfare of all types of horses. On the basis of published information on cyathostomes of horses, six recommendations are made for reducing the development and spread of anthelmintic resistant nematodes. The need for restraint in the use of anthelmintics, the application of epidemiological principles of worm control and a greater emphasis on pasture management are the principal recommendations.
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102
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Coles GC. Warble fly and sheep scab. Vet Rec 1995; 136:423. [PMID: 7625065 DOI: 10.1136/vr.136.16.423-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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103
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104
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Grimshaw WT, Hunt KR, Hong C, Coles GC. Detection of anthelmintic resistant nematodes in sheep in southern England by a faecal egg count reduction test. Vet Rec 1994; 135:372-4. [PMID: 7831741 DOI: 10.1136/vr.135.16.372] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
On five farms identified by in vitro tests to have benzimidazole resistance, and on one farm with apparent anthelmintic failure, faecal egg count reduction tests were performed using benzimidazoles, levamisole and ivermectin. With benzimidazoles efficacy was less than 70 per cent on all farms, confirming the validity of the in vitro tests to detect benzimidazole resistance. On two farms levamisole had an efficacy of less than 90 per cent but laboratory tests failed to demonstrate levamisole resistance. Ivermectin reduced egg counts by 100 per cent on all farms.
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105
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Coles GC, Giordano-Fenton DJ, Tritschler JP. Efficacy of moxidectin against nematodes in naturally infected sheep. Vet Rec 1994; 135:38-9. [PMID: 7975073 DOI: 10.1136/vr.135.2.38] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
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.
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106
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Hunt KR, Hong C, Coles GC, Jones TO. Benzimidazole-resistant Trichostrongylus colubriformis from goats in central England. Vet Rec 1994; 134:420-1. [PMID: 8036773 DOI: 10.1136/vr.134.16.420] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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107
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Coles GC, Borgsteede FH, Geerts S. Recommendations for the control of anthelmintic resistant nematodes of farm animals in the EU. Vet Rec 1994; 134:205-6. [PMID: 8171806 DOI: 10.1136/vr.134.9.205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
As a result of a recent European Union meeting on anthelmintic resistant nematodes of farm animals, a list was made of nine proposals for research and five to control anthelmintic resistance. The most important were the need to have standardised and new tests to monitor the development and spread of resistant nematodes in sheep, goats, horses, cattle and pigs, and for education of veterinary surgeons and farmers in the optimal control strategies to be used to delay the development of anthelmintic resistance in nematodes.
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108
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Small AJ, Coles GC. Detection of anthelmintic resistance by culture in vitro of parasitic stages of ovine nematodes. Vet Parasitol 1993; 51:163-6. [PMID: 8128582 DOI: 10.1016/0304-4017(93)90209-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Exsheathed L3 larvae of Haemonchus contortus were cultured at 38.5 degrees C in a complex medium supporting growth to adult worms. Although there was a clear difference in response between susceptible and benzimidazole/ivermectin/closantel resistant H. contortus using thiabendazole, the test failed to differentiate satisfactorily between the strains using ivermectin or closantel.
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109
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Coles GC, Harris TJ, Hong C. Activity of morantel citrate against strains of benzimidazole-resistant nematodes of sheep in the United Kingdom. Vet Rec 1993; 133:156-7. [PMID: 8236701 DOI: 10.1136/vr.133.7.156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The activity of morantel citrate (5.94 mg/kg base) was determined in laboratory tests against field isolates of benzimidazole-resistant nematodes. Its efficacies against adult and seven-day-old worms were 100 per cent and 100 per cent for Cooperia curticei, 95.1 per cent and 69.8 per cent for Haemonchus contortus and 100 per cent and 82 per cent for Ostertagia circumcincta. Morantel citrate was 100 per cent effective against benzimidazole-susceptible Nematodirus battus and Trichostrongylus vitrinus, and it reduced faecal egg counts by 97.9 per cent in sheep infected naturally with benzimidazole-resistant H contortus and O circumcincta.
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110
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Drescher KM, Rogers EJ, Bruce JI, Katz N, Dias LC, Coles GC. Response of drug resistant isolates of Schistosoma mansoni to antischistosomal agents. Mem Inst Oswaldo Cruz 1993; 88:89-95. [PMID: 8246759 DOI: 10.1590/s0074-02761993000100014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The susceptibility of four isolates of Schistosoma mansoni (BH, MAP, MPR-1 and K) to four multiple doses of anti-schistosomal agents (hycanthone, niridazole, oxamniquine, and praziquantel) were evaluated in infected female Swiss albino mice. These schistosomal isolates had been maintained in the laboratory without further drug pressure for 20 to 30 generations. Multiple dosage regimens were used for each drug against each isolate of S. mansoni to generate ED50 (effective dose 50%) values. Results demonstrated that the K isolate is resistant to niridazole, the MPR-1 isolate to oxamniquine, and the MAP isolate to both hycanthone and oxamniquine. The BH isolate was susceptible to all drugs and was used as the reference isolate. All isolates were susceptible to parziquantel. The significance of the difference in response of the MPR-1 and MAP isolates is discussed. These results confirm the resistance of these isolates of S. mansoni to three schistosomicides and demonstrate that the resistance of these isolates are stable over long periods of time without exposure to drugs.
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111
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Coles GC, Bauer C, Borgsteede FH, Geerts S, Klei TR, Taylor MA, Waller PJ. World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) methods for the detection of anthelmintic resistance in nematodes of veterinary importance. Vet Parasitol 1992; 44:35-44. [PMID: 1441190 DOI: 10.1016/0304-4017(92)90141-u] [Citation(s) in RCA: 1057] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Methods have been described to assist in the detection of anthelmintic resistance in strongylid nematodes of ruminants, horses and pigs. Two tests are recommended, an in vivo test, the faecal egg count reduction test for use in infected animals, and an in vitro test, the egg hatch test for detection of benzimidazole resistance in nematodes that hatch shortly after embryonation. Anaerobic storage for submission of faecal samples from the field for use in the in vitro test is of value and the procedure is described. The tests should enable comparable data to be obtained in surveys in all parts of the world.
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112
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Webster KA, Rankin M, Goddard N, Tarry DW, Coles GC. Immunological and feeding studies on antigens derived from the biting fly, Stomoxys calcitrans. Vet Parasitol 1992; 44:143-50. [PMID: 1441185 DOI: 10.1016/0304-4017(92)90152-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Pairs of rabbits were immunised with three antigenic preparations derived from Stomoxys calcitrans gut, abdominal section and whole flies. Immunoblotting studies demonstrated that a humoral response was mounted against eight antigens from the gut preparation and 12 each from the abdominal and whole fly preparations. In vitro feeding experiments showed higher mortality between Days 4 and 7 in the group of flies which had fed upon blood from rabbits inoculated with the gut derived antigen. This group also produced the lowest percentage of viable eggs (15.5%).
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113
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Hong C, Hunt KR, Harris TJ, Coles GC, Grimshaw WT, McMullin PF. A survey of benzimidazole resistant nematodes in sheep in three countries of southern England. Vet Rec 1992; 131:5-7. [PMID: 1502771 DOI: 10.1136/vr.131.1.5] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Faecal samples were collected from 209 randomly selected sheep farms in southern England, and the nematode eggs extracted were tested by an egg hatch assay and by a larval development test for their resistance to benzimidazoles. Benzimidazole resistance was found on 35 per cent of farms tested in East Sussex, 44 per cent in Oxfordshire and 61 per cent in West Sussex.
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114
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Coles GC, Tarry DW, Sinclair IJ. Vaccination against warble fly? PARASITOLOGY TODAY (PERSONAL ED.) 1992; 8:236; author reply 236. [PMID: 15463627 DOI: 10.1016/0169-4758(92)90122-i] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
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115
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Coles GC, Roush RT. Slowing the spread of anthelmintic resistant nematodes of sheep and goats in the United Kingdom. Vet Rec 1992; 130:505-10. [PMID: 1641966 DOI: 10.1136/vr.130.23.505] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Anthelmintic resistant nematodes pose an increasing threat to animal welfare and lamb production on lowland sheep farms in the United Kingdom. Based on published information on anthelmintic resistance in nematodes and insecticide resistance in arthropods, seven recommendations are made for reducing the development and spread of anthelmintic resistant nematodes. The two most important are probably to prevent the introduction of resistant worms through the purchase of stock and to reduce the reliance on frequent anthelmintic treatments by using epidemiological principles of nematode control.
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116
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117
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Hunt KR, Hong C, Coles GC, Simpson VR, Neal C. Benzimidazole-resistant Cooperia curticei from Cornwall, England. Vet Rec 1992; 130:164. [PMID: 1566544 DOI: 10.1136/vr.130.8.164] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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118
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Katz N, Rocha RS, de Souza CP, Coura Filho P, Bruce JI, Coles GC, Kinoti GK. Efficacy of alternating therapy with oxamniquine and praziquantel to treat Schistosoma mansoni in children following failure of first treatment. Am J Trop Med Hyg 1991; 44:509-12. [PMID: 1905880 DOI: 10.4269/ajtmh.1991.44.509] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Two hundred children infected with Schistosoma mansoni were treated with either 20 mg/kg oxamniquine or 60 mg/kg praziquantel. Cure rates (about 85%) were similar as was the percentage reduction (80%) in egg counts in uncured children. Treatment with the alternative drug of children not cured with the first treatment resulted in negative stools in 11 of 12 cases examined one month after the second round of therapy. In order to minimize the risk of the development of drug resistance, our data suggest that infected patients be treated with one drug, and therapeutic failures with another. Evidence from experiments in mice with isolates obtained after failures of one treatment in children suggests that therapeutic failure does not necessarily indicate the presence of drug-resistant schistosomes. The value of using mice to assess drug resistance in schistosomes is questioned.
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119
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120
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121
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Maloney MD, Semprevivo LH, Coles GC. A comparison of the glycolipid compositions of cercarial and adult Schistosoma mansoni and their associated hosts. Int J Parasitol 1990; 20:1091-3. [PMID: 2074137 DOI: 10.1016/0020-7519(90)90055-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Glycolipid patterns of cercarial and adult Schistosoma mansoni were determined and compared with those of Biomphalaria glabrata snails and mouse (BALB/c strain) red blood cells by high-performance thin-layer chromatography. Differences in glycolipid content were found between cercariae and adult worms and between these stages and their respective host tissues.
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122
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Babish JG, Coles GC, Tritschler JP, Gutenmann WH, Lisk DJ. Toxicity and tissue residue depletion of levamisole hydrochloride in young goats. Am J Vet Res 1990; 51:1126-30. [PMID: 2389890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Toxicity and tissue residue depletion studies were conducted in young goats, using an oral drench formulation of levamisole hydrochloride. In the target animal toxicity study, 3 groups of 5 goats each were given levamisole orally to provide approximately 11.88, 23.76, or 35.64 mg of levamisole HCl/kg/d for 3 consecutive days; a fourth group of 5 goats served as untreated controls. Blood samples were taken for analysis of levamisole 1 day prior to dosing and 1, 2, 3, 4, and 7 days following the third dose. At the 35.64-mg/kg dose, 2 of 5 goats responded with typical cholinergic signs of toxicosis on each of the 3 days of dosing. The times for the onset of clinical signs of toxicosis ranged from 18 to 63 minutes, with an average duration of 32 minutes. Administration of 23.76 mg of levamisole HCl/kg resulted in hyperactive behavior in 1 of 5 goats only on the first day of dosing; no abnormal behavior was observed in any of the 5 goats following the second or third dose of levamisole HCl at 23.76 mg/kg. Untoward effects were not seen in the 5 goats dosed at 11.88 mg of levamisole HCl/kg or in the controls during the 3-day dosing period or in the following 7-day observation period. Overall, the observed signs of toxicosis did not become more severe, affect more goats, or persist for a longer period on subsequent dosing days.(ABSTRACT TRUNCATED AT 250 WORDS)
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123
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Coles GC. How widespread are benzimidazole-resistant nematodes of sheep? Vet Rec 1990; 126:629. [PMID: 2378052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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124
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Enos A, Coles GC. Effect of benzimidazole drugs on tubulin in benzimidazole resistant and susceptible strains of Caenorhabditis elegans. Int J Parasitol 1990; 20:161-7. [PMID: 2332276 DOI: 10.1016/0020-7519(90)90096-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
An in vitro assay was used to determine efficacy and if side resistance was present to benzimidazole anthelmintics tested against Caenorhabditis elegans after selection with albendazole. Side resistance was present to all the benzimidazoles tested, except for oxibendazole and parbendazole. At a concentration of 1 mM, all of the drugs, except thiabendazole, were effective in killing 100% of the albendazole susceptible worms. Tubulin from albendazole resistant and susceptible C. elegans was isolated and run on polyacrylamide gels. Western blots with anti-tubulin antibody showed that the albendazole resistant strain had an altered tubulin. Electron microscopy of albendazole-treated drug resistant worms showed microtubules throughout the intestinal cells. Microtubules were not observed in albendazole-treated drug susceptible worms.
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125
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Coles GC. Recent advances in laboratory models for evaluation of helminth chemotherapy. THE BRITISH VETERINARY JOURNAL 1990; 146:113-9. [PMID: 2184914 DOI: 10.1016/0007-1935(90)90003-l] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Extensive research on nematodes of veterinary importance has resulted in new tests based on incubation of parasitic nematodes in culture media, with a variety of detection systems including visual observation, inhibition of aggregation, reduced secretion of acetylcholinesterase and electronic motility measurements. There has been a proliferation of tests to detect benzimidazole resistant nematodes including egg embryonation, egg hatch, larval motility, differences in esterases, and tubulin binding by labelled benzimidazoles. A simple larval development test, which detects resistance to all types of anthelmintics, is likely to become the preferred test for evaluation of resistance in nematodes of grazing animals. By contrast the relative unimportance of trematodes and cestodes from a commercial point of view has resulted in few recent developments in models for evaluating chemotherapy. But the emergence of drug resistant strains of both schistosomes and liver fluke indicates the need for simple tests to detect resistance.
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