Interactions between gastrointestinal nematode parasites and diarrhoea in sheep: Pathogenesis and control

Williams, Andrew R.; Palmer, D.G.

doi:10.1016/j.tvjl.2011.10.009

Cited by 19 publications

(20 citation statements)

References 63 publications

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“…The parasitic nematodes that colonize the gastrointestinal tract of ruminants cause decreased appetite, reduced growth rate and persistent diarrhoea [36]. Virtually all ruminants grazing improved pastures are infected, either clinically or sub-clinically, with nematode members of the family Trichostrongylidae, of which T .…”

Section: Discussionmentioning

confidence: 99%

Suppression of ovine lymphocyte activation by Teladorsagia circumcincta larval excretory-secretory products

McNeilly

Rocchi

Bartley

et al. 2013

Vet Res

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Teladorsagia circumcincta is an important pathogenic nematode of sheep. It has been demonstrated previously that stimulation of murine T lymphocytes with excretory-secretory (ES) products derived from fourth stage larvae of T. circumcincta (Tci-L4-ES) results in de novo expression of Foxp3, a transcription factor intimately involved in regulatory T cell function. In the current study, Foxp3+ T cell responses in the abomasum and the effects of Tci-L4-ES on ovine peripheral blood mononuclear cells (PBMC) following T. circumcincta infection were investigated. T. circumcincta infection resulted in a significant increase in numbers of abomasal Foxp3+ T cells, but not an increase in the proportion of T cells expressing Foxp3. Unlike in mice, Tci-L4-ES was incapable of inducing T cell Foxp3 expression but instead suppressed mitogen-induced and antigen-specific activation and proliferation of ovine PBMC in vitro. This effect was heat labile, suggesting that it is mediated by protein(s). Suppression was associated with up-regulation of interleukin-10 (IL-10) mRNA, and specific monoclonal antibody neutralisation of IL-10 resulted in a 50% reduction in suppression, indicating involvement of the IL-10 signaling pathway. Suppression was significantly reduced in PBMC isolated from T. circumcincta infected vs. helminth-naïve lambs, and this reduction in suppression was associated with an increase in Tci-L4-ES antigen-specific T cells within the PBMC. In conclusion, we have identified a mechanism by which T. circumcincta may modulate the host adaptive immune response, potentially assisting survival of the parasite within the host. However, the impact of Tci-L4-ES-mediated lymphocyte suppression during T. circumcincta infection remains to be determined.

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Section: Discussionmentioning

confidence: 99%

Suppression of ovine lymphocyte activation by Teladorsagia circumcincta larval excretory-secretory products

McNeilly

Rocchi

Bartley

et al. 2013

Vet Res

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“…17,19,20 Phenotypic culling of ewes with severe dag will reduce the risk of breech-strike among the current generation of sheep, but will contribute only modest genetic improvement, because the major source of genetic improvement within a wool flock comes from the ram. [23][24][25] It is now well established that susceptibility to gastrointestinal parasites and hypersensitivity scouring are two separate genetic traits in Merino sheep. For example, in a survey of five Victorian sheep farms, up to 40% of lactating ewes were scouring by the end of winter, despite adequate control programs for internal parasites.…”

Section: Odds Ratios and 95% Confidence Interval (Ci) Of Risk Factorsmentioning

confidence: 99%

“…20,21 In south-eastern Australia, persistent diarrhoea regularly occurs in winter and spring. 23,25,26 Thus, decreasing the incidence of diarrhoea is not as simple as selecting sheep with low FECs to increase resistance to internal parasites. 22 Diarrhoea in high winter rainfall areas can be caused by internal parasites, bacterial enteritis or poorly defined 'nutritional factors' .…”

Section: Odds Ratios and 95% Confidence Interval (Ci) Of Risk Factorsmentioning

confidence: 99%

“…For example, in a survey of five Victorian sheep farms, up to 40% of lactating ewes were scouring by the end of winter, despite adequate control programs for internal parasites. 23,25,26 Most measurements of breech characteristics for selection purposes are conducted on sheep aged less than 18 months, with recommendations to select as early as lamb marking because of their high susceptibility to and risk of breech-strike. 23 Internal parasites can cause diarrhoea when sheep have an increased susceptibility to worm infections, and hence a high faecal egg count (FEC).…”

Section: Odds Ratios and 95% Confidence Interval (Ci) Of Risk Factorsmentioning

confidence: 99%

“…Alternatively, immunologically competent sheep can develop diarrhoea following a hypersensitivity response to the ingestion of infective larvae (low FEC). [23][24][25] It is now well established that susceptibility to gastrointestinal parasites and hypersensitivity scouring are two separate genetic traits in Merino sheep. 23,25,26 Thus, decreasing the incidence of diarrhoea is not as simple as selecting sheep with low FECs to increase resistance to internal parasites.…”

Section: Odds Ratios and 95% Confidence Interval (Ci) Of Risk Factorsmentioning

confidence: 99%

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Breech‐strike on mulesed, clipped and unmulesed Merino ewes and hoggets in south‐eastern Australia

2014

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Early-season treatment of unmulesed sheep prevented most breech-strikes during spring and early summer on both hoggets and breeding ewes, confirming it as a short- to medium-term option for the control of breech-strike. Some benefits were associated with the use of clips but, to control breech-strike, clipped sheep should be treated the same as unmulesed sheep. Genetic selection to reduce the prevalence of dag will be required for future strategies to control breech-strike on Merino sheep in south-eastern Australia.

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Contribution of the Immune Response in the Ileum to the Development of Diarrhoea caused by Helminth Infection: Studies with the Sheep Model

Hassan

Chua

Kaur

et al. 2022

Funct Integr Genomics

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Gastrointestinal helminths are a global health issue, for humans as well as domestic animals. Most studies focus on the tissues that are infected with the parasite, but here we studied the ileum, a tissue that is rarely infected by helminths. We tested whether inflammation in the ileum contributes to the development and severity of diarrhoea, by comparing sheep that are susceptible (n = 4) or resistant (n = 4) to the disease. We analyzed the ileum transcriptome using RNASeq sequencing approach and various bioinformatics tools including FastQC, STAR, featureCounts, DESeq2, DAVID, clusterProfiler, Cytoscape (ClusterONE) and EnrichR. We identified 243 differentially expressed genes (DEGs), of which 118 were up-regulated and 125 were down-regulated DEGs in the diarrhoea-susceptible animals compared to the diarrhoea-resistant animals. The resulting DEGs were functionally enriched for biological processes, pathways and gene set enrichment analysis. The up-regulated DEGs suggested that an inflammatory immune response was coupled with genes involved in ‘Th2 immune response’ and ‘anti-inflammatory response’. The down-regulated DEGs were related to ion transport, muscle contraction and pathways preventing inflammation. We conclude that i) susceptibility to helminth-induced diarrhoea involves an inflammatory response at a non-infectious site; ii) down-regulation of pathways preventing inflammation can contribute to the severity of diarrhoea; and iii) genes involved in anti-inflammatory responses can reduce the inflammation and diarrhoea.

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Interactions between gastrointestinal nematode parasites and diarrhoea in sheep: Pathogenesis and control

Cited by 19 publications

References 63 publications

Suppression of ovine lymphocyte activation by Teladorsagia circumcincta larval excretory-secretory products

Suppression of ovine lymphocyte activation by Teladorsagia circumcincta larval excretory-secretory products

Breech‐strike on mulesed, clipped and unmulesed Merino ewes and hoggets in south‐eastern Australia

Contribution of the Immune Response in the Ileum to the Development of Diarrhoea caused by Helminth Infection: Studies with the Sheep Model

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