Decision making on helminths in cattle: diagnostics, economics and human behaviour

Charlier, Johannes; Waele, Valérie De; Ducheyne, Els; Voort, Mariska van der; Velde, Fiona Vande; Claerebout, Edwin

doi:10.1186/s13620-016-0073-6

Cited by 48 publications

(33 citation statements)

References 41 publications

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“…DHR is a cell-permeable fluorophore that fluoresces in the presence of peroxide and peroxynitrite (two forms of ROS). For each fish we measured: (1) baseline ROS production in unstimulated granulocytes and (2) induced ROS production in Phorbol 12-myristate 13-acetate (PMA)-stimulated granulocytes. Here, we focus on the second metric (see Fig.…”

Section: Tapeworm Infection Prevalence Differs Among Natural Sticklebackmentioning

confidence: 99%

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Recent evolution of extreme cestode growth suppression by a vertebrate host

Weber

Steinel

Shim

et al. 2016

Preprint

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Parasites can be a major cause of natural selection on hosts, which consequently evolve a variety of strategies to avoid, eliminate, or tolerate infection. When ecologically similar host populations present disparate infection loads, this natural variation can reveal immunological strategies underlying adaptation to infection and population divergence. For instance, the tapeworm Schistocephalus solidus persistently infects between 0% to 80% of threespine stickleback (Gasterosteus aculeatus) in lakes on Vancouver Island. To test whether these heterogeneous infection rates are due to evolved differences in immunity, we experimentally exposed lab-reared fish from high-and low-infection populations, which are not known to differ in natural exposure risk, to controlled doses of Schistocephalus. We observed heritable between-population differences in several immune traits: fish from the naturally uninfected population initiated a stronger granulocyte response to Schistocephalus infection, and their granulocytes constitutively generated threefold more reactive oxygen species (ROS). Despite these immunological differences, Schistocephalus was equally successful at establishing initial infections in both host populations. However, the low-infection fish dramatically suppressed tapeworm growth relative to high-infection fish, and parasite size was intermediate in F1hybrid hosts. Our results show that stickleback recently evolved heritable variation in their capacity to suppress helminth growth. Comparative data from many from natural populations indicate that growth suppression is widespread but not universal and, when present, is associated with reduced infection prevalence. Host suppression of helminth somatic growth may be an important immune strategy that aids in parasite clearance, or in mitigating the fitness costs of persistent infection.Significance: Large parasites remain a persistent source of morbidity and mortality in humans, domesticated animals, and wildlife. Hosts are subject to strong natural selection to eliminate or tolerate these parasite infections. Here, we document the recent evolution of a striking form of resistance by a vertebrate host (threespine stickleback) against its cestode parasite (Schistocephalus solidus). After Pleistocene glacial retreat, marine stickleback colonized freshwater lakes, encountered Schistocephalus, and evolved varying levels of resistance to it. We show that a heavily-and a rarely-infected population of stickleback have similar resistance to Schistocephalus colonization, but rarely-infected fish suppress parasite growth by orders of magnitude. These populations represent ends of a natural continuum of cestode growth suppression, which is associated with reduced infection prevalence.

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Section: Tapeworm Infection Prevalence Differs Among Natural Sticklebackmentioning

confidence: 99%

“…Helminth parasites (trematodes, nematodes, cestodes) currently infect approximately 24% of humanity (1), undermine agricultural productivity (2,3), and threaten conservation of some wild populations (4). These social, economic, and environmental costs motivate substantial interest in how vertebrate hosts combat helminth infection.…”

Section: Introductionmentioning

confidence: 99%

Recent evolution of extreme cestode growth suppression by a vertebrate host

Weber

Steinel

Shim

et al. 2016

Preprint

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“…Gastrointestinal (GI) parasitism is among the most important production‐limiting diseases of grazing ruminants (Charlier et al., ). Inadequate anthelmintic drug uses, among other factors, have led to the current scenario of anthelmintic resistance, considered a main concern in veterinary medicine today (Kaplan & Vidyashankar, ).…”

Section: Introductionmentioning

confidence: 99%

“…Gastrointestinal (GI) parasitism is among the most important production-limiting diseases of grazing ruminants (Charlier et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Pharmaco‐parasitological evaluation of the ricobendazole plus levamisole nematodicidal combination in cattle

Cantón

Ceballos

Dominguez

et al. 2017

Vet Pharm & Therapeutics

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The goals of the current study were to evaluate the potential pharmacokinetic (PK) interactions and the clinical efficacy occurring after the subcutaneous (s.c.) administration of ricobendazole (RBZ) and levamisole (LEV) given both separately and coadministered to calves naturally infected with susceptible gastrointestinal nematodes.The clinical efficacy was shown in two seasons, winter and spring, with predominance of different nematode populations. Groups of 15 calves were treated with RBZ alone, LEV alone and RBZ + LEV combination, and an untreated group was kept as a Control.RBZ and LEV plasma concentrations were quantified by HPLC. The clinical efficacy was determined by the faecal egg count reduction test. RBZ and LEV have similar plasma persistence, being detected in plasma over 24 hr post-treatment. No PK interactions were observed after the combined treatment, with similar PK parameters (p > .05) obtained for the single-drug and the combination-based strategy. In winter, the observed clinical efficacies were 96%, 99% and 100% for groups treated with RBZ, LEV and RBZ + LEV, respectively; however, in spring, the efficacies were 95%, 93% and 96% for the same groups. Remarkably, the combination was the only treatment that achieved 100% clinical efficacy against both Haemonchus spp and Ostertagia spp in winter; but the increased presence of Ostertagia spp. in spring (28% in untreated group) determined a tendency to reduced efficacies compared to winter time (only 10% of Ostertagia spp. in untreated group), even for the combined treatment. Overall, in a scenario where the nematode population is susceptible, the RBZ + LEV treatment may be a valid combination in cattle to delay the development of resistance, especially in winter when this combination achieved 100% of efficacy. Thus, selection of anthelmintic resistance will never occur. In fact, this is one of the greatest challenges for the whole cattle production system: to be one step ahead of anthelmintic resistance.

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“…Given that the costs of parasite control measures are typically borne by the farmer, there is a pivotal role for the development of models and computational tools to assess the farm‐level economic impact of nematode as well as other infections. Several models have already been developed, but they need further translation and support to evolve from research to practice (Charlier et al., ). In addition, these models are mostly restricted to dairy cattle farms and need to be extended to include beef, sheep, goat and pig production systems.…”

Section: Socio‐economicsmentioning

confidence: 99%

Mind the gaps in research on the control of gastrointestinal nematodes of farmed ruminants and pigs

Charlier

Thamsborg

Bartley

et al. 2017

Transbound Emerg Dis

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Gastrointestinal (GI) nematode control has an important role to play in increasing livestock production from a limited natural resource base and to improve animal health and welfare. In this synthetic review, we identify key research priorities for GI nematode control in farmed ruminants and pigs, to support the development of roadmaps and strategic research agendas by governments, industry and policymakers. These priorities were derived from the DISCONTOOLS gap analysis for nematodes and follow-up discussions within the recently formed Livestock Helminth Research Alliance (LiHRA). In the face of ongoing spread of anthelmintic resistance (AR), we are increasingly faced with a failure of existing control methods against GI nematodes. Effective vaccines against GI nematodes are generally not available, and anthelmintic treatment will therefore remain a cornerstone for their effective control. At the same time, consumers and producers are increasingly concerned with environmental issues associated with chemical parasite control. To address current challenges in GI nematode control, it is crucial to deepen our insights into diverse aspects of epidemiology, AR, host immune mechanisms and the socio-psychological aspects of nematode control. This will enhance the development, and subsequent uptake, of the new diagnostics, vaccines, pharma-/nutraceuticals, control methods and decision support tools required to respond to the spread of AR and the shifting epidemiology of GI nematodes in response to climatic, land-use and farm husbandry changes. More emphasis needs to be placed on the upfront evaluation of the economic value of these innovations as well as the socio-psychological aspects to prioritize research and facilitate uptake of innovations in practice. Finally, targeted regulatory guidance is needed to create an innovation-supportive environment for industries and to accelerate the access to market of new control tools.

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Decision making on helminths in cattle: diagnostics, economics and human behaviour

Cited by 48 publications

References 41 publications

Recent evolution of extreme cestode growth suppression by a vertebrate host

Recent evolution of extreme cestode growth suppression by a vertebrate host

Pharmaco‐parasitological evaluation of the ricobendazole plus levamisole nematodicidal combination in cattle

Mind the gaps in research on the control of gastrointestinal nematodes of farmed ruminants and pigs

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