Acquired immunity against Cooperia spp. and Ostertagia spp. in calves: effect of level of exposure and timing of the midsummer increase

Ploeger, H.W.; Kloosterman, A.; Rietveld, F.W.

doi:10.1016/0304-4017(94)00711-k

Cited by 25 publications

(9 citation statements)

References 12 publications

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“…Faecal avoidance changes the timing of when hosts come into contact with parasites on pasture; this delay in L3 ingestions can delay the acquisition of immunity resulting in the parasite burden peaking later in the grazing season. This could have substantial consequences for production, as delaying the acquisition of immunity can lead to pathogenic parasitism shifting towards the time when livestock are older and normally productive [26]. As host susceptibility varies over the year with age and physiological status [44], [49], [60], changes in the timing of infection could further alter transmission dynamics.…”

Section: Discussionmentioning

confidence: 99%

Modelling Parasite Transmission in a Grazing System: The Importance of Host Behaviour and Immunity

et al. 2013

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Parasitic helminths present one of the most pervasive challenges to grazing herbivores. Many macro-parasite transmission models focus on host physiological defence strategies, omitting more complex interactions between hosts and their environments. This work represents the first model that integrates both the behavioural and physiological elements of gastro-intestinal nematode transmission dynamics in a managed grazing system. A spatially explicit, individual-based, stochastic model is developed, that incorporates both the hosts’ immunological responses to parasitism, and key grazing behaviours including faecal avoidance. The results demonstrate that grazing behaviour affects both the timing and intensity of parasite outbreaks, through generating spatial heterogeneity in parasite risk and nutritional resources, and changing the timing of exposure to the parasites’ free-living stages. The influence of grazing behaviour varies with the host-parasite combination, dependent on the development times of different parasite species and variations in host immune response. Our outputs include the counterintuitive finding that under certain conditions perceived parasite avoidance behaviours (faecal avoidance) can increase parasite risk, for certain host-parasite combinations. Through incorporating the two-way interaction between infection dynamics and grazing behaviour, the potential benefits of parasite-induced anorexia are also demonstrated. Hosts with phenotypic plasticity in grazing behaviour, that make grazing decisions dependent on current parasite burden, can reduce infection with minimal loss of intake over the grazing season. This paper explores how both host behaviours and immunity influence macro-parasite transmission in a spatially and temporally heterogeneous environment. The magnitude and timing of parasite outbreaks is influenced by host immunity and behaviour, and the interactions between them; the incorporation of both regulatory processes is required to fully understand transmission dynamics. Understanding of both physiological and behavioural defence strategies will aid the development of novel approaches for control.

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Section: Discussionmentioning

confidence: 99%

Modelling Parasite Transmission in a Grazing System: The Importance of Host Behaviour and Immunity

et al. 2013

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“…The disease is particularly important in young animals in the first or second grazing season, but adult cattle may also harbor clinical infections. Unlike most gastrointestinal nematodes of cattle, development of immunity against the parasite is slow to arise, and is seldom completely protective against reinfection (Armour, 1985;Ploeger et al, 1995). This prolonged susceptibility to the detrimental effects of the parasite is a principle reason why the parasite causes severe economic losses.…”

Section: Introductionmentioning

confidence: 99%

Inhibition of bovine T lymphocyte responses by extracts of the stomach worm Ostertagia ostertagi

Gómez-Muñoz

Canals-Caballero²,

Almerı́a

et al. 2004

Veterinary Parasitology

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Lowered immune responses during bovine ostertagiosis have been reported in both in vivo and in vitro assay systems. In the present study we have employed three different life cycle stages of the nematode Ostertagia ostertagi to determine if products of this economically important parasite inhibit in vitro proliferation of Con A-stimulated cells from uninfected animals. We have demonstrated an inhibitory effect upon the growth of Con A-stimulated lymphocytes after addition of fourth stage larval (L4) soluble extract (L4SE) to the cultures. In contrast, extracts from the third stage larvae (L3) had little or no inhibitory activity. The suppressive products were also shown to be secreted by the late L4. The suppressive activity is reversible if the L4 products are removed from culture. There is no immediate effect on proliferating cells and the L4SE must be in culture for 24-48 h before suppression is observable. The L4SE caused slight but not statistically significant decreases in the percentage of T cells and increases in B cell percentages in cultures when compared with cultures stimulated with Con A alone. No changes were seen in percentage of cells positive for markers for CD4, CD8, gammadelta T cells, or monocytes/macrophages as a consequence of the addition of L4SE. In contrast, there was a strong and significant reduction in the expression of the IL-2 receptors in cells cultured in the presence of the worm extract. There was no evidence of either necrosis or apoptosis resulting from the presence of L4 products in culture. The expression of messenger RNA for interleukin-2, -4, -13, tumor necrosis factor-alpha (TNF-alpha), and gamma-interferon (gamma-IFN) was decreased when L4SE was included in cultures of Con A-stimulated cells compared to cultures stimulated with Con A only. In contrast, messenger RNA expression of transforming growth factor-beta (TGF-beta) and interleukin-10 (IL-10) was increased in cells growing in the presence of L4 products. The potential role of these cytokines during ostertagiosis is discussed.

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“…A consequence of these assumptions would be an under- or over-estimation of calf performance during parasitism, as was indeed the case in the validation of the model by Ward (2006b) . This could arise, for example, by over or under expression of the immune function to parasites as a consequence of nutrition ( Ploeger et al, 1995 , Coop and Kyriazakis, 1999 ).…”

Section: Discussionmentioning

confidence: 99%

A simulation model to investigate interactions between first season grazing calves and Ostertagia ostertagi

Berk

Bishop

Forbes

et al. 2016

Veterinary Parasitology

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Acquired immunity against Cooperia spp. and Ostertagia spp. in calves: effect of level of exposure and timing of the midsummer increase

Cited by 25 publications

References 12 publications

Modelling Parasite Transmission in a Grazing System: The Importance of Host Behaviour and Immunity

Modelling Parasite Transmission in a Grazing System: The Importance of Host Behaviour and Immunity

Inhibition of bovine T lymphocyte responses by extracts of the stomach worm Ostertagia ostertagi

A simulation model to investigate interactions between first season grazing calves and Ostertagia ostertagi

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