Comparative use of faecal egg count reduction test, egg hatch assay and beta-tubulin codon 200 genotyping in small strongyles (cyathostominae) before and after benzimidazole treatment.
Abstract: A survey on benzimidazole (BZ) resistance in small strongyles was performed on three farms in the tenth region in Chile. Samples from a total of 100 horses were tested using the faecal egg count reduction test (FECRT), the egg hatch assay (EHA) and an allele-specific PCR for the detection of beta-tubulin isotype 1 genes coding for phenylalanine (phe) or tyrosine (tyr) at codon 200. In the past, BZ-type drugs have been used within anthelmintic campaigns on all the three farms. This has predictably led to a high degree of BZ resistance at the Valdivia and Riñihue farms and to a lesser degree at the Frutillar farm, as demonstrated by all the three tests. The FECRT indicated resistance in every farm by faecal egg count reductions (FECR) of 27% (S.D. +/- 33), 26.5% (S.D. +/- 26.9) and 83.9% (S.D. +/- 22.8) for the Valdivia, Riñihue and Frutillar farms, respectively. With the EHA, the following mean LD(50) values were found before and after treatment with fenbendazole (FBZ): 0.093, 0.141 and 0.066 microg TBZ/ml and 0.149, 0.158 and 0.091 microg TBZ/ml, respectively, for the Valdivia, Riñihue and Frutillar samples. The corresponding LD(96) values were 0.222, 0.263 and 0.188 microg TBZ/ml before treatment and 0.316, 0.322 and 0.221 microg TBZ/ml after treatment, indicating BZ resistance in all the cases. Genotyping was performed on more than 1700 single larvae, at least 10 per faecal sample, for 98 pre- and 66 post-treatment samples. Despite a general trend toward higher percentages of phe/tyr and tyr/tyr individuals following treatment, no statistically significant difference was found between these two and the phe/phe genotype percentages. However, a significantly negative correlation was detected between the LD(50) values and the phe/phe percentages and there was a positive correlation between the FECRT results and the phe/phe percentages. Thus, there seems to be a difference in the significance of the codon 200 polymorphism in the mechanisms of BZ resistance in small strongyles of the horse and sheep trichostrongyles.
Publication Date: 2002-09-19 PubMed ID: 12237141DOI: 10.1016/s0304-4017(02)00197-8Google Scholar: Lookup
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- Comparative Study
- Journal Article
Summary
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This research examines benzimidazole resistance in small strongyles (a type of parasite) in horses, using three techniques; faecal egg count reduction test, egg hatch assay and DNA testing of beta-tubulin genes. Results from three different farms indicate varying levels of drug resistance.
Introduction
- The study was aimed at evaluating the resistance of a type of horse parasite, small strongyles, against benzimidazole (BZ), a common anthelmintic drug. The research was carried out on three farms located in the tenth region of Chile.
Methodology
- The study used samples from a total of hundred horses and measured BZ resistance using three different methods. One method is the faecal egg count reduction test (FECRT), which measures the amount of parasite eggs in the animal’s faeces before and after drug treatment.
- Another testing method used was the egg hatch assay (EHA) that checks how well the eggs of the parasites can hatch after exposure to the drug.
- The third method was an allele-specific PCR, a type of genetic testing, for detecting beta-tubulin genes, which are heavily involved in BZ resistance. More specifically, the study looked for the presence of beta-tubulin isotype 1 genes coding for phenylalanine (phe) or tyrosine (tyr) at codon 200. These represent genetic markers of BZ resistance.
Observations and Data
- Resistance to BZ was found at all three farm sites, albeit to varying degrees. Farms located in Valdivia and Riñihue showed a higher degree of resistance than the third farm in Frutillar.
- Genotyping was performed on over 1700 single larvae from both pre- and post-treatment samples. While there was a general trend towards higher percentages of resistance-associated genotypes (phe/tyr and tyr/tyr) after treatment, the study did not find a statistically significant difference for the phe/phe genotype percentages.
Significant Findings
- A significant negative correlation was observed between the LD(50) values and the phe/phe percentages, and a positive correlation between the FECRT results and the phe/phe percentages, indicating a potential difference in the significance of the codon 200 polymorphism in BZ resistance mechanisms.
Conclusion
- The study results suggest the existence of BZ resistance among small strongyles in horses. While all three testing methods showed the presence of resistance to some degree, the observations indicate that the mechanisms of resistance may differ from those seen in other parasites, namely sheep trichostrongyles.
Cite This Article
APA
von Samson-Himmelstjerna G, von Witzendorff C, Sievers G, Schnieder T.
(2002).
Comparative use of faecal egg count reduction test, egg hatch assay and beta-tubulin codon 200 genotyping in small strongyles (cyathostominae) before and after benzimidazole treatment.
Vet Parasitol, 108(3), 227-235.
https://doi.org/10.1016/s0304-4017(02)00197-8 Publication
Researcher Affiliations
- Institute of Parasitology, Hannover School of Veterinary Medicine, Buenteweg 17, 30559 Hannover, Germany. gvsamson@tiho-hannover.de
MeSH Terms
- Animals
- Antinematodal Agents / pharmacology
- Antinematodal Agents / therapeutic use
- Codon
- DNA, Helminth / genetics
- Drug Resistance / genetics
- Feces / parasitology
- Fenbendazole / pharmacology
- Fenbendazole / therapeutic use
- Genotype
- Horses
- Lethal Dose 50
- Male
- Parasite Egg Count / veterinary
- Polymerase Chain Reaction
- Statistics, Nonparametric
- Strongyle Infections, Equine / drug therapy
- Strongyle Infections, Equine / parasitology
- Strongylida / genetics
- Strongylida / growth & development
- Strongylida / metabolism
- Tubulin / genetics
Citations
This article has been cited 6 times.- Morrison AA, Mitchell S, Mearns R, Richards I, Matthews JB, Bartley DJ. Phenotypic and genotypic analysis of benzimidazole resistance in the ovine parasite Nematodirus battus.. Vet Res 2014 Dec 9;45:116.
- Lake SL, Matthews JB, Kaplan RM, Hodgkinson JE. Determination of genomic DNA sequences for beta-tubulin isotype 1 from multiple species of cyathostomin and detection of resistance alleles in third-stage larvae from horses with naturally acquired infections.. Parasit Vectors 2009 Sep 25;2 Suppl 2(Suppl 2):S6.
- Traversa D, von Samson-Himmelstjerna G, Demeler J, Milillo P, Schürmann S, Barnes H, Otranto D, Perrucci S, di Regalbono AF, Beraldo P, Boeckh A, Cobb R. Anthelmintic resistance in cyathostomin populations from horse yards in Italy, United Kingdom and Germany.. Parasit Vectors 2009 Sep 25;2 Suppl 2(Suppl 2):S2.
- Corning S. Equine cyathostomins: a review of biology, clinical significance and therapy.. Parasit Vectors 2009 Sep 25;2 Suppl 2(Suppl 2):S1.
- von Samson-Himmelstjerna G, Coles GC, Jackson F, Bauer C, Borgsteede F, Cirak VY, Demeler J, Donnan A, Dorny P, Epe C, Harder A, Höglund J, Kaminsky R, Kerboeuf D, Küttler U, Papadopoulos E, Posedi J, Small J, Várady M, Vercruysse J, Wirtherle N. Standardization of the egg hatch test for the detection of benzimidazole resistance in parasitic nematodes.. Parasitol Res 2009 Sep;105(3):825-34.
- Alvarez-Sánchez MA, Pérez-García J, Cruz-Rojo MA, Rojo-Vázquez FA. Anthelmintic resistance in trichostrongylid nematodes of sheep farms in Northwest Spain.. Parasitol Res 2006 Jun;99(1):78-83.
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