Practices to optimise gastrointestinal nematode control on sheep, goat and cattle farms in Europe using targeted (selective) treatments

Charlier, Johannes; Morgan, Eric R.; Rinaldi, Laura; Dijk, Jan van; Demeler, Janina; Höglund, Johan; Hertzberg, Hubertus; Ranst, B Van; Hendrickx, Guy; Vercruysse, Jozef; Kenyon, Fiona

doi:10.1136/vr.102512

Cited by 157 publications

(153 citation statements)

References 53 publications

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“…One strategy that aims to achieve this is targeted selective treatment (TST), which involves the treatment of selected individuals that require, or will benefit from, treatment, as opposed to treatment of the entire group (van Wyk et al., 2006). Individuals are generally identified as needing to receive treatment on the basis of their level of parasitism or performance (Charlier et al., 2014). Although TST strategies have been developed and applied successfully in lambs (Greer et al., 2009, Kenyon et al., 2009, Kenyon et al., 2013), there are considerably fewer studies on cattle, with the first insights into the application of TST having occurred relatively recently (Greer et al., 2010, McAnulty et al., 2011, Höglund et al., 2013, O'Shaughnessy et al., 2014a, O'Shaughnessy et al., 2015a, O'Shaughnessy et al., 2015b).…”

Section: Introductionmentioning

confidence: 99%

Modelling the consequences of targeted selective treatment strategies on performance and emergence of anthelmintic resistance amongst grazing calves

Berk

Laurenson

Forbes

et al. 2016

International Journal for Parasitology: Drugs and Drug Resistan

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The development of anthelmintic resistance by helminths can be slowed by maintaining refugia on pasture or in untreated hosts. Targeted selective treatments (TST) may achieve this through the treatment only of individuals that would benefit most from anthelmintic, according to certain criteria. However TST consequences on cattle are uncertain, mainly due to difficulties of comparison between alternative strategies. We developed a mathematical model to compare: 1) the most ‘beneficial’ indicator for treatment selection and 2) the method of selection of calves exposed to Ostertagia ostertagi, i.e. treating a fixed percentage of the population with the lowest (or highest) indicator values versus treating individuals who exceed (or are below) a given indicator threshold. The indicators evaluated were average daily gain (ADG), faecal egg counts (FEC), plasma pepsinogen, combined FEC and plasma pepsinogen, versus random selection of individuals. Treatment success was assessed in terms of benefit per R (BPR), the ratio of average benefit in weight gain to change in frequency of resistance alleles R (relative to an untreated population). The optimal indicator in terms of BPR for fixed percentages of calves treated was plasma pepsinogen and the worst ADG; in the latter case treatment was applied to some individuals who were not in need of treatment. The reverse was found when calves were treated according to threshold criteria, with ADG being the best target indicator for treatment. This was also the most beneficial strategy overall, with a significantly higher BPR value than any other strategy, but its degree of success depended on the chosen threshold of the indicator. The study shows strong support for TST, with all strategies showing improvements on calves treated selectively, compared with whole-herd treatment at 3, 8, 13 weeks post-turnout. The developed model appeared capable of assessing the consequences of other TST strategies on calf populations.

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Section: Introductionmentioning

confidence: 99%

Modelling the consequences of targeted selective treatment strategies on performance and emergence of anthelmintic resistance amongst grazing calves

Berk

Laurenson

Forbes

et al. 2016

International Journal for Parasitology: Drugs and Drug Resistan

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“…The worldwide production of small ruminants is strongly impacted by gastrointestinal parasites that cause high mortality rates (HOSTE & TORRES-ACOSTA, 2011;STEAR et al, 2011;KNOX et al, 2012;FALZON et al, 2014), as well as losses resulting from subclinical infections that are reflected in low productivity (CHARLIER et al, 2014). In tropical countries, Haemonchus contortus is the most prevalent nematode in herds, causing severe losses due to the high pathogenic pressure it exerts through hematophagy (KASSAI, 1999).…”

Section: Introductionmentioning

confidence: 99%

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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“…The use of ocular mucosa color (FAMACHA), parasite load on fecal examination, and weight gain of animals (COSTA et al, 2011;CHARLIER et al, 2014a) may also help to identify the best time for a chemical intervention. Other options include integrated management practices with the intention of minimizing the effects of parasitic infection through strategic and selective treatment schemes (HAMMERSCHMIDT et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

Multiple anthelmintic resistance in Southern Brazil sheep flocks

Oliveira

Riet-Correa

Estima-Silva

et al. 2017

Rev. Bras. Parasitol. Vet.

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Gastrointestinal parasites represent an important cause of reduced productivity of sheep worldwide. As anthelmintic are still the main control tool for these parasites, this work evaluated the efficacy of commercially available active principles in 22 sheep flocks in the southern region of Rio Grande do Sul, Brazil. In each farm 10 sheep were randomly distributed in seven groups with the following treatments: abamectin; albendazole; closantel; levamisole; monepantel; trichlorphon and no anthelmintic (control). All flocks showed resistance to at least three anthelmintics and in 20 farms only two products demonstrated efficacy for parasitic control. In two farms, there was no susceptibility to the six active principles tested. The results of this study provide evidence that the common commercially available anthelmintic are not assuring effective chemical control of gastrointestinal parasitic infections in ovine flocks in the southern region of Rio Grande do Sul. Monepantel, the newest introduced drug in the Brazilian market was not effective in 18% of the flocks tested, confirming that the parasitic resistance can be established quickly after the introduction of new molecules mainly when alternative program of parasite control is not performed.Keywords: Sheep breeding, gastrointestinal nematodes, chemical control, resistance. ResumoAs parasitoses gastrintestinais representam importante causa de queda na produtividade na ovinocultura mundial. Como a utilização de anti-helmínticos é, ainda, a principal forma de controle parasitário, o presente estudo avaliou a eficácia de princípios ativos comercialmente disponíveis, em 22 rebanhos ovinos da região Sul do Rio Grande do Sul, Brasil. Em cada propriedade foram utilizados 10 ovinos divididos em sete grupos que receberam os seguintes tratamentos: abamectina; albendazole; closantel; levamisole; monepantel; e triclorfon. Um grupo permaneceu como controle, sem tratamento anti-helmíntico. Nas 22 propriedades do estudo houve resistência, no mínimo, a três anti-helmínticos. Em 20 propriedades apenas dois produtos demonstraram eficácia para o controle parasitário. Em duas propriedades não houve sensibilidade aos seis princípios ativos testados. Os resultados do presente estudo demonstraram que os anti-helmínticos disponíveis no marcado Brasileiro não asseguram um controle parasitário efetivo nos rebanhos ovinos da região Sul do Rio Grande do Sul, incluindo o monepantel que foi ineficaz em 18% dos rebanhos testados, confirmando que a resistência dos parasitos aos princípios ativos pode se estabelecer rapidamente após a introdução de novas moléculas, principalmente quando programas alternativos de controle não são realizados.Palavras-chave: Ovinocultura, nematoides gastrintestinais, controle químico de parasitos, resistência.

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Practices to optimise gastrointestinal nematode control on sheep, goat and cattle farms in Europe using targeted (selective) treatments

Cited by 157 publications

References 53 publications

Modelling the consequences of targeted selective treatment strategies on performance and emergence of anthelmintic resistance amongst grazing calves

Modelling the consequences of targeted selective treatment strategies on performance and emergence of anthelmintic resistance amongst grazing calves

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

Multiple anthelmintic resistance in Southern Brazil sheep flocks

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