Methods to determine resistance to anthelmintics when continuing larval development occurs

Lyndal-Murphy, M.; Swain, A. J.; Pepper, P.M.

doi:10.1016/j.vetpar.2013.11.002

Cited by 37 publications

(34 citation statements)

References 21 publications

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“…(1992), as well as the upper 95% CI as suggested by Lyndal-Murphy et al. (2014), from which we categorised three conditions:

Efficacious treatment, when mean FECR% and upper CI ≥ 95% and lower CI ≥ 90%;

Reduced efficacy, when mean FECR% and upper CI < 95% and lower CI < 90%;

Inconclusive, when none of the above conditions were met.

…”

Section: Methodsmentioning

confidence: 60%

“…The inclusion of untreated animals in a FECRT has been recommended to detect changes in the FEC of a herd not related with the treatment, and for the correction of such fluctuations in the estimation of drug efficacy (Coles et al., 1992, Lyndal-Murphy et al., 2014). However, the inclusion of a control group is based on the assumption that treated and untreated animals with comparable FEC share similar worm burdens, which may not be always the case in cattle (Michel, 1967, Michel, 1969).…”

Section: Discussionmentioning

confidence: 99%

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Efficacy of ivermectin against gastrointestinal nematodes of cattle in Denmark evaluated by different methods for analysis of faecal egg count reduction

Pena-Espinoza

Thamsborg

Denwood

et al. 2016

International Journal for Parasitology: Drugs and Drug Resistan

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The efficacy of ivermectin (IVM) against gastrointestinal nematodes in Danish cattle was assessed by faecal egg count reduction test (FECRT). Six cattle farms with history of clinical parasitism and avermectin use were included. On the day of treatment (Day 0), 20 naturally infected calves per farm (total n = 120) were stratified by initial faecal egg counts (FEC) and randomly allocated to a treatment group dosed with 0.2 mg IVM kg−1 body weight s.c. (IVM; n = 10) or an untreated control group (CTL; n = 10). Individual FEC were obtained at Day 0 and Day 14 post-treatment and pooled faeces by group were cultured to isolate L3 for detection of Ostertagia ostertagi and Cooperia oncophora by qPCR. Treatment efficacies were analysed using the recommended WAAVP method and two open-source statistical procedures based on Bayesian modelling: ‘eggCounts’ and ‘Bayescount’. A simulation study evaluated the performance of the different procedures to correctly identify FEC reduction percentages of simulated bovine FEC data representing the observed real data. In the FECRT, reduced IVM efficacy was detected in three farms by all procedures using data from treated animals only, and in one farm according to the procedures including data from treated and untreated cattle. Post-treatment, O. ostertagi and C. oncophora L3 were detected by qPCR in faeces of treated animals from one and three herds with declared reduced IVM efficacy, respectively. Based on the simulation study, all methods showed a reduced performance when FEC aggregation increased post-treatment and suggested that a treatment group of 10 animals is insufficient for the FECRT in cattle. This is the first report of reduced anthelmintic efficacy in Danish cattle and warrants the implementation of larger surveys. Advantages and caveats regarding the use of Bayesian modelling and the relevance of including untreated cattle in the FECRT are discussed.

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“…(1992), as well as the upper 95% CI as suggested by Lyndal-Murphy et al. (2014), from which we categorised three conditions:

Efficacious treatment, when mean FECR% and upper CI ≥ 95% and lower CI ≥ 90%;

Reduced efficacy, when mean FECR% and upper CI < 95% and lower CI < 90%;

Inconclusive, when none of the above conditions were met.

…”

Section: Methodsmentioning

confidence: 60%

Section: Discussionmentioning

confidence: 99%

Efficacy of ivermectin against gastrointestinal nematodes of cattle in Denmark evaluated by different methods for analysis of faecal egg count reduction

Pena-Espinoza

Thamsborg

Denwood

et al. 2016

International Journal for Parasitology: Drugs and Drug Resistan

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“…In Brazil, its reported effectiveness rate was higher than that of other drugs tested in eight studies involving sheep (AMARANTE et al, 1992;THOMAZ-SOCCOL et al, 1996;MELO et al, 2003;ROSALINSKI-MORAES et al, 2007;CRUZ et al, 2010;VERÍSSIMO et al, 2012;SPRENGER et al, 2013) and in three studies involving goats (MATTOS et al, 2000;RODRIGUES et al, 2007;LIMA et al, 2010a). Levamisole has also been reported to be more effective than other antiparasitics in Canada (FALZON et al, 2013), Denmark (PENA-ESPINOZA et al, 2014) and Australia (LYNDAL-MURPHY et al, 2014). It is worth noting that levamisole showed a higher effectiveness rate than other anthelmintics, but that it has not been entirely effective (95%) in most studies, and that resistance to this drug has been reported.…”

Section: Developments In Research and The Effectiveness Of Anthelmintmentioning

confidence: 97%

Overview of anthelmintic resistance of gastrointestinal nematodes of small ruminants in Brazil

Salgado

Santos

2016

Rev. Bras. Parasitol. Vet.

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Frequent and inappropriate use of all classes of antiparasitic drugs in small ruminants has led to failures in their effectiveness, culminating in a global problem of anthelmintic resistance. Brazil stands out as one of the world's leaders in publications about anthelmintic resistance, and for having the most numerous reports of this resistance in small ruminants in the Americas. These studies have involved mainly the fecal egg count reduction test (FECRT) and its correlation with field management practices. In vivo effectiveness testing is conducted in areas where livestock is of greater economic significance, e.g., in the South (sheep) and Northeast (goats), or is important for research and economic centers, such as the Southeast (sheep). The most widely studied species is sheep, for which the widest range of drugs is also evaluated. Despite significant advances achieved in molecular research, laboratory analyses should include knowledge about the reality in the field so that they can become feasible for the producer. Moreover, molecular studies can be underpinned by the analysis of field studies, such as the maintenance of antiparasitic effectiveness over time and the mechanisms involved in this process.Keywords: Small ruminants, anthelmintic resistance, sheep, goat, gastrointestinal nematodes. ResumoO uso frequente e inapropriado de todas as classes de antiparasitários em pequenos ruminantes levou a falhas de eficácia, culminando na problemática global de resistência anti-helmíntica. O Brasil destaca-se como sendo um dos pioneiros nas publicações com resistência anti-helmíntica no mundo e por ter o maior número de relatos em pequenos ruminantes na América. Essas pesquisas envolvem principalmente o teste da redução da contagem de ovos nas fezes (TRCOF) e sua correlação com as práticas de manejo utilizadas no campo. Os estudos de testes de eficácia in vivo localizam-se em áreas onde há maior importância dos rebanhos como nas Regiões Sul (ovinos) e Nordeste (caprinos), ou com importância em polos de pesquisa e econômicos, como a região Sudeste (ovinos). Ovina é a espécie mais estudada e com maior gama de drogas avaliadas. Mesmo com grande avanço em pesquisas moleculares, as análises laboratoriais devem envolver o conhecimento da realidade do campo para que possam se tornar viáveis ao produtor. Além disso, a análise dos estudos de campo pode nortear estudos moleculares como, por exemplo, a manutenção da eficácia das drogas ao longo dos anos e os mecanismos envolvidos em tal processo.

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“…Assays for detecting resistance in parasites primarily rely on phenotypic analyses, which are widely applied in livestock (Lyndal-Murphy et al, 2014). Standardization of this molecular tool is a critical advance, particularly because the phenotypic tests offer low sensitivity, as a greater number of excreted eggs in dog feces does not necessarily indicate a higher parasite load.…”

Section: Resultsmentioning

confidence: 99%

Development of a new amplification-refractory mutation system for detection of a single nucleotide polymorphism linked to drug resistance in Ancylostoma caninum

Lf¹,

Ém²

2015

Genet. Mol. Res.

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ABSTRACT. Single nucleotide polymorphisms at codons 167, 198, and 200 in the β-tubulin isotype 1 gene have been associated with benzimidazole resistance. Until now, the only mutation observed in Ancylostoma caninum was at codon 200 of this gene. However, the standardized methodologies used to detect mutations in this species are faulty. The objective of this study was to standardize a molecular technique based on amplification-refractory mutation system-polymerase chain reaction (ARMS-PCR) for detecting the mutation at codon 200 in the A. caninum β-tubulin isotype 1 gene. Controls were synthesized both for the absence of the mutation, using conventional PCR, and for the presence of the mutation, using the Megaprimer-PCR technique. After (2015) standardization of the ARMS-PCR using the controls, the technique was validated through an analysis of 75 A. caninum DNA samples, followed by sequencing. The results revealed that the developed technique has high sensitivity, specificity, and reproducibility, which allow its application in the field.

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Methods to determine resistance to anthelmintics when continuing larval development occurs

Cited by 37 publications

References 21 publications

Efficacy of ivermectin against gastrointestinal nematodes of cattle in Denmark evaluated by different methods for analysis of faecal egg count reduction

Efficacy of ivermectin against gastrointestinal nematodes of cattle in Denmark evaluated by different methods for analysis of faecal egg count reduction

Overview of anthelmintic resistance of gastrointestinal nematodes of small ruminants in Brazil

Development of a new amplification-refractory mutation system for detection of a single nucleotide polymorphism linked to drug resistance in Ancylostoma caninum

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