Interactions between Ostertagia ostertagi and Cooperia oncophora in calves

Hilderson, Hans; Vercruysse, Jozef; Claerebout, Edwin; Graaf, Dirk C. de; Fransen, J.; Berghen, P.

doi:10.1016/0304-4017(94)00656-w

Cited by 23 publications

(14 citation statements)

References 25 publications

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“…It is difficult to distinguish between species in faecal samples, with large numbers of eggs produced by Cooperia worms implying threshold values of FEC may not be representative of O. ostertagi burdens. Although there does not appear to be inter-species interactions (Kloosterman et al., 1984, Satrija and Nansen, 1993, Hilderson et al., 1995) there are important consequences for levels of protein loss, hence modification of the model to account for Cooperia would prove beneficial in future development.…”

Section: Discussionmentioning

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: Discussionmentioning

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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“…Monospecific and concurrent artificial infections of O. ostertagi and Cooperia suggested an absence of inter-species interactions (Kloosterman et al 1984 ; Satrija and Nansen, 1993 ; Hilderson et al 1995 ). Concurrent infections did, however, show greater than additive FEC in comparison with the two monospecific infections (Kloosterman et al 1984 ; Satrija and Nansen, 1993 ; Hilderson et al 1995 ), thought to be a consequence of enhanced pathological effects (Parkins et al 1990 ). This has been suggested to reflect the fact that Cooperia increases the rate of protein loss leading to a reduced growth rate and growth requirements.…”

Section: Discussionmentioning

confidence: 99%

A stochastic model to investigate the effects of control strategies on calves exposed toOstertagia ostertagi

et al. 2016

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SUMMARYPredicting the effectiveness of parasite control strategies requires accounting for the responses of individual hosts and the epidemiology of parasite supra- and infra-populations. The first objective was to develop a stochastic model that predicted the parasitological interactions within a group of first season grazing calves challenged by Ostertagia ostertagi, by considering phenotypic variation amongst the calves and variation in parasite infra-population. Model behaviour was assessed using variations in parasite supra-population and calf stocking rate. The model showed the initial pasture infection level to have little impact on parasitological output traits, such as worm burdens and FEC, or overall performance of calves, whereas increasing stocking rate had a disproportionately large effect on both parasitological and performance traits. Model predictions were compared with published data taken from experiments on common control strategies, such as reducing stocking rates, the ‘dose and move’ strategy and strategic treatment with anthelmintic at specific times. Model predictions showed in most cases reasonable agreement with observations, supporting model robustness. The stochastic model developed is flexible, with the potential to predict the consequences of other nematode control strategies, such as targeted selective treatments on groups of grazing calves.

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“…In general, very little is known about these cells, despite numerous studies indicating the importance of GLs in parasite immunology. GLs have been associated with resistance to O. ostertagi, Trichostrongylus colubriformis, H. contortus, and other helminths in the past (43)(44)(45)(46). The exact effector mechanism used by GLs against worms is still unclear, but as granulysin was detected in mucus, granule exocytosis could be one of these effector mechanisms.…”

Section: Discussionmentioning

confidence: 99%

Granule Exocytosis of Granulysin and Granzyme B as a Potential Key Mechanism in Vaccine-Induced Immunity in Cattle against the Nematode Ostertagia ostertagi

et al. 2013

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dOstertagia ostertagi is considered one of the most economically important bovine parasites. As an alternative to anthelmintic treatment, an experimental host-protective vaccine was previously developed on the basis of ASP proteins derived from adult worms. Intramuscular injection of this vaccine, combined with QuilA as an adjuvant, significantly reduced fecal egg counts by 59%. However, the immunological mechanisms triggered by the vaccine are still unclear. Therefore, in this study, the differences in immune responses at the site of infection, i.e., the abomasal mucosa, between ASP-QuilA-vaccinated animals and QuilA-vaccinated control animals were investigated on a transcriptomic level by using a whole-genome bovine microarray combined with histological analysis. Sixty-nine genes were significantly impacted in animals protected by the vaccine, 48 of which were upregulated. A correlation study between the parasitological parameters and gene transcription levels showed that the transcription levels of two of the upregulated genes, those for granulysin (GNLY) and granzyme B (GZMB), were negatively correlated with cumulative fecal egg counts and total worm counts, respectively. Both genes were also positively correlated with each other and with another upregulated gene, that for the IgE receptor subunit (FCER1A). Surprisingly, these three genes were also correlated significantly with CMA1, which encodes a mast cell marker, and with counts of mast cells and cells previously described as globule leukocytes. Furthermore, immunohistochemical data showed that GNLY was present in the granules of globule leukocytes and that it was secreted in mucus. Overall, the results suggest a potential role for granule exocytosis by globule leukocytes, potentially IgE mediated, in vaccine-induced protection against O. ostertagi.

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Interactions between Ostertagia ostertagi and Cooperia oncophora in calves

Cited by 23 publications

References 25 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

A stochastic model to investigate the effects of control strategies on calves exposed toOstertagia ostertagi

Granule Exocytosis of Granulysin and Granzyme B as a Potential Key Mechanism in Vaccine-Induced Immunity in Cattle against the Nematode Ostertagia ostertagi

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