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ABSTRACT: Anthelmintic resistance among parasites of sheep and goats has been known to occur for at least four decades. Both species
of host have similar genera of nematodes, but the nematodes in goat herds usually develop anthelmintic resistance more rapidly.
In vitro tests show higher ED50 values in goats than in flocks of sheep. Sheep and goats differ in many ways; for example, goats have a higher metabolic
rate and require higher dose rates for drugs. The immune system of goats is also different. Additionally, these animals are
reared under different management systems, i.e. sheep graze pastures and goats browse bushes, and lambing/kidding periods
are different. Most anthelmintics used in goats have not been licensed for this animal species, and correct dose rates have
rarely been experimentally determined. Possible explanations for such differences are discussed.
Keywordsanthelmintic resistance–sheep–goats
Helminthologia 04/2012; 48(3):137-144. · 0.77 Impact Factor
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ABSTRACT: The objective of the study was to compare the in vitro egg hatch test (EHT), larval development test (LDT) and in vivo faecal egg count reduction test (FECR test) for the detection of benzimidazole resistance in equine strongyles. The presence of resistant or susceptible strongyle populations was determined in 25 stud farms using the in vivo FECR test and in vitro EHT. On the basis of the FECR values, resistance to fenbendazole was detected on 15 of the 25 farms (60%). The ED50 value (anthelmintic concentration producing 50% inhibition of hatching) for suspected resistant populations varied from 0.110 to 0.222 microg/ml thiabendazole (TBZ). Final LD50 values (anthelmintic concentration inhibiting development of 50% of eggs into L3 infective larvae) above 0.029 microg/ml TBZ in the in vitro larval development test on samples from 11 stud farms revealed the presence of populations of small strongyles suspected of being benzimidazole-resistant.
Veterinary Research Communications 06/2003; 27(4):281-8. · 0.82 Impact Factor
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ABSTRACT: The objective of the study was to compare the in vitro egg hatch test (EHT), larval development test (LDT) and in vivo faecal egg count reduction test (FECR test) for the detection of benzimidazole resistance in equine strongyles. The presence of resistant or susceptible strongyle populations was determined in 25 stud farms using the in vivo FECR test and in vitro EHT. On the basis of the FECR values, resistance to fenbendazole was detected on 15 of the 25 farms (60%). The ED50 value (anthelmintic concentration producing 50% inhibition of hatching) for suspected resistant populations varied from 0.110 to 0.222 g/ml thiabendazole (TBZ). Final LD50 values (anthelmintic concentration inhibiting development of 50% of eggs into L3 infective larvae) above 0.029 g/ml TBZ in the in vitro larval development test on samples from 11 stud farms revealed the presence of populations of small strongyles suspected of being benzimidazole-resistant.
Veterinary Research Communications 04/2003; 27(4):281-288. · 0.82 Impact Factor
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ABSTRACT: The present study included 19 stud farms, including 243 horses, that were investigated for the occurrence of anthelmintic resistant cyathostomes. The number of horses on the farms varied from nine to more than 100, and horses of all ages were included. A minimum of seven horses were used for faecal egg count reduction (FECR) tests. The anthelmintics included were: fenbendazole (paste formulation), ivermectin (paste formulation) and pyrantel (powder). Resistance to benzimidazoles was detected on 14 farms, with FECR values ranging from 65.1 to 86.3%. Larval cultures after fenbendazole treatment revealed exclusively cyathostome larvae. Ivermectin was tested on eight farms and proved to be effective on all. Pyrantel was tested on two farms and FECR test indicated high efficacy (92-97%). Egg hatch assay (EHA) results showed that mean concentrations of thiabendazole that inhibited hatching in 50% of the eggs (ED(50)) in resistant populations were over 0.1 microg ml(-1). The results of our study suggest widespread resistance to fenbendazole in equine cyathostomes in Slovakia, and possible strategies to delay anthelmintic resistance are discussed briefly.
Veterinary Parasitology 01/2001; 94(1-2):67-74. · 2.58 Impact Factor
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ABSTRACT: A larvoscopic examination of faeces collected from localities inhibited by chamois in the Tatra National Park (TANAP) in 1997 demonstrated the presence of the lung nematodes Muellerius spp. (likely to be M. tenuispiculatus and M. capillaris) and Neostrongylus linearis. The overall prevalence of lung nematodes in chamois herds in TANAP was 48.4% with prevalences of 45.6% and 11.9% for Muellerius spp. and N. linearis, respectively. No significant differences in lung nematode prevalences were observed in the biotopes of TANAP with prevalence values of 44.9% being recorded in the High Tatras and 58.5% in the Belianske Tatras. Individual species were in equal proportion in both biotopes, although N. linearis was significantly less prevalent (11.2-13.8%). The prevalence of lung nematodes in the High Tatras varied from 25.0 to 84.2% within individual localities, while in the Belianske Tatras it was more proportionate (50.0-85.7%). In the High Tatras, the prevalence of lung nematodes in the chamois herds peaked during August, declining to its lowest in October. A similar prevalence was also recorded for Muellerius species, while the minimum prevalence of N. linearis was found in July. In the Belianske Tatras, the prevalence of lung nematodes including both species of Muellerius peaked in July and gradually decreased until October. On the other hand, N. linearis was most prevalent in October. The mean L1 count per gram faeces was low (7.6 +/- 13.2 larvae g-1).
Journal of Helminthology 10/1999; 73(3):259-63. · 1.38 Impact Factor
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ABSTRACT: The present study included 19 stud farms, including 243 horses, that were investigated for the occurrence of anthelmintic resistant cyathostomes. The number of horses on the farms varied from nine to more than 100, and horses of all ages were included. A minimum of seven horses were used for faecal egg count reduction (FECR) tests. The anthelmintics included were: fenbendazole (paste formulation), ivermectin (paste formulation) and pyrantel (powder). Resistance to benzimidazoles was detected on 14 farms, with FECR values ranging from 65.1 to 86.3%. Larval cultures after fenbendazole treatment revealed exclusively cyathostome larvae. Ivermectin was tested on eight farms and proved to be effective on all. Pyrantel was tested on two farms and FECR test indicated high efficacy (92–97%). Egg hatch assay (EHA) results showed that mean concentrations of thiabendazole that inhibited hatching in 50% of the eggs (ED50) in resistant populations were over 0.1 μg ml−1. The results of our study suggest widespread resistance to fenbendazole in equine cyathostomes in Slovakia, and possible strategies to delay anthelmintic resistance are discussed briefly.
Veterinary Parasitology.
