Multiple resistance of gastrointestinal nematodes to nine different drugs in a sheep flock in southern Brazil

Cezar, Alfredo Skrebsky; Toscan, Gustavo; Camillo, Giovana; Sangioni, Luís Antônio; Ribas, Henrique Olmedo; Vogel, Fernanda Silveira Flôres

doi:10.1016/j.vetpar.2010.06.013

Cited by 86 publications

(53 citation statements)

References 20 publications

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“…With regard to the efficacy noted with the drugs administered individually or in combination, the results of this study corroborate those presented by Sczesny-Moraes et al (2010), but contradict those reported by Soccol et al (2004), Buzzulini et al (2007), Cezar et al (2010), and Holsback et al (2013), all of which found higher efficacies with the administration of drug combinations compared to those obtained with individual drugs.…”

Section: Groupssupporting

confidence: 72%

“…If this animal were removed from the group, the reevaluated FECR rate would increase to 94%, which is comparable to those of G3 and G5 (93% and 95%, respectively), suggesting that fenbendazole neither contributed to the improvement of the efficacy of the treatment, nor was it responsible for any antagonism (Table 2). Cezar et al (2010) proposed that random combinations of drugs are not advisable as they might increase the treatment costs without adding to the efficacy of their anthelminthic activity, and might also speed up the problem of development of cross-parasitic resistance.…”

Section: Groupsmentioning

confidence: 99%

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Anthelmintic efficiency of doramectin, fenbendazole, and nitroxynil, in combination or individually, in sheep worm control

Holsback

Luppi

Silva

et al. 2016

Rev. Bras. Parasitol. Vet.

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The anthelmintic efficiency of doramectin, fenbendazole, and nitroxynil, used individually or in combination, was determined by the Fecal Egg Count Reduction (FECR) test and cultivation of larvae of anthelminthic-treated sheep grouped as follows: G1 (doramectin), G2 (fenbendazole), G3 (nitroxynil), G4 (doramectin + fenbendazole), G5 (doramectin + nitroxynil), G6 (fenbendazole + nitroxynil), G7 (doramectin + nitroxynil + fenbendazole), G8 (untreated). In addition to individually used doramectin and fenbendazole, the helminths were also resistant to the combination of doramectin + fenbendazole; nitroxynil + fenbendazole; and doramectin + nitroxynil + fenbendazole, with their FECR rates ranging from 62-83%. The helminths showed possible nitroxynil-resistance, but had low resistance when the drug was administered in combination with doramectin. The evaluation of individual helminth species revealed that fenbendazole was fully effective against Cooperia; doramectin (G1), moderately effective against Haemonchus and insufficiently active against Cooperia; nitroxynil, effective against Haemonchus and insufficiently active against Cooperia. It was concluded from the results that herd nematodes are resistant to doramectin, fenbendazole, and nitroxynil, and that the combined use of the drugs not only fails to significantly improve the anthelmintic efficiency against Haemonchus and Cooperia, but is also cost-ineffective.Keywords: Parasitic resistance, Haemonchus, Cooperia, small ruminants, anthelmintic association. ResumoEficiências da doramectina, fenbendazole e nitroxynil, utilizados individualmente ou associadamente, foram determinadas através do Teste de Redução na Contagem de Ovos nas Fezes (RCOF) e cultivo de larvas. Os grupos experimentais foram os seguintes: G1 (ovinos tratados com doramectina), G2 (fenbendazole), G3 (nitroxynil), G4 (doramectina + fenbendazole), G5 (doramectina + nitroxynil), G6 (fenbendazole + nitroxynil), G7 (doramectina + fenbendazole + nitroxynil) e G8, não tratados. Os helmintos foram considerados resistentes a doramectina e ao fenbendazole isoladamente e às associações doramectina + fenbendazole, fenbendazole + nitroxynil, e doramectina + fenbendazole + nitroxynil, com taxas de RCOF variando de 62-83%. Helmintos foram considerados suspeitos de resistência ao nitroxynil e apresentaram baixa resistência, quando esta droga foi associada à doramectina. Dos tratamentos isolados, o fenbendazole demonstrou total eficácia (100%) contra Cooperia. Doramectina (G1) foi moderadamente efetiva contra Haemonchus e insuficientemente ativa contra Cooperia, e o nitroxynil efetivo contra Haemonchus (93,2%) e insuficientemente ativo contra Cooperia (0%). Concluiu-se neste estudo que os nematódeos do rebanho são resistentes à doramectina, fenbendazole e nitroxynil, e que, ainda que associadas, não devem ser utilizadas no rebanho por não melhorarem a eficiência anti-helmíntica nem a efetividade contra Haemonchus e Cooperia e por não apresentarem custo-benefício justificado.

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Section: Groupssupporting

confidence: 72%

Section: Groupsmentioning

confidence: 99%

Anthelmintic efficiency of doramectin, fenbendazole, and nitroxynil, in combination or individually, in sheep worm control

Holsback

Luppi

Silva

et al. 2016

Rev. Bras. Parasitol. Vet.

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“…Subsequent reports of multiple resistance to the macrocyclic lactones ivermectin and moxidectin (CONDER et al, 1993;SHOOP et al, 1993) raised the possibility of cross-resistance between them (MOLENTO et al, 1999). In addition to other drugs, Cezar et al 2010 andCruz et al 2010 reported resistance to nitroxynil, a narrow spectrum anthelmintic that had until then been effective against Haemonchus spp.…”

Section: History Of Ahr In Small Ruminants In Brazil and Around The Wmentioning

confidence: 99%

“…However, it was found that these combinations could fail, particularly when there was already resistance to one or more drugs, although the use of combinations was found to be valid when inserted in integrated programs of drug resistance management and underpinned by parasitological examinations (LEATHWICK & BESIER, 2014). In Brazil, resistance to various combinations of antiparasitics were reported in sheep in the state of Paraná by Thomaz-Soccol et al (1996) and ThomazSoccol et al (2004), in Rio Grande do Sul by Echevarria et al (1996) and Cezar et al (2010), and in Mato Grosso do Sul by Sczesny-Moraes et al (2010) (see Table 1). …”

Section: History Of Ahr In Small Ruminants In Brazil and Around The Wmentioning

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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“…For the purposes of this guideline, AR may be simply defined as a heritable change in susceptibility to an anthelmintic in a population of parasitic nematodes such that a dose which normally provides ≥95% clearance of adult worms provides ≤80% clearance. Anthelmintic resistance is arguably the greatest threat to the sustainable control of helminthoses in the short-to medium-term and the problem is compounded by the fact that many of these parasite populations are resistant to more than one class of anthelmintic (van Wyk et al, 1997;Love et al, 2003;Anziani et al, 2004;Wrigley et al, 2006;Sargison et al, 2007;Sutherland et al, 2008;Gasbarre et al, 2009a,b;Cezar et al, 2010;Baker et al, 2012;Molento et al, 2012;Reinemeyer, 2012). Despite the scarcity of well-structured surveys, it is generally accepted that the prevalence of AR is increasing globally in the ruminant livestock industries and in horses.…”

Section: Introductionmentioning

confidence: 99%

World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) Guideline: Anthelmintic combination products targeting nematode infections of ruminants and horses

Geary

Hosking

Skuce

et al. 2012

Veterinary Parasitology

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a b s t r a c tIncreasing threats from anthelmintic resistant nematode populations warrant and motivate a reappraisal of chemotherapeutic strategies for nematode control in ruminant livestock and horses. The objective of this paper is to present a guideline for the evaluation of products containing two or more constituent anthelmintic actives in a single dosage form for the treatment of nematode infections in these animals. At present, regulatory policies on the approval of such products vary across jurisdictions, and this World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guideline should enable the harmonization of the requirements. This guideline makes clear recommendations on the minimal standards needed, but stresses that registration dossiers for combination anthelmintic products submitted for approval must conform to the standards and practices already established in existing guidelines for anthelmintics.

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Multiple resistance of gastrointestinal nematodes to nine different drugs in a sheep flock in southern Brazil

Cited by 86 publications

References 20 publications

Anthelmintic efficiency of doramectin, fenbendazole, and nitroxynil, in combination or individually, in sheep worm control

Anthelmintic efficiency of doramectin, fenbendazole, and nitroxynil, in combination or individually, in sheep worm control

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

World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) Guideline: Anthelmintic combination products targeting nematode infections of ruminants and horses

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