Assessment of accuracy of liver fluke diagnostic tests using the gold standard of total worm counts.

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dc.citation.volume54
dc.contributor.authorDowling A
dc.contributor.authorLawrence KE
dc.contributor.authorHowe L
dc.contributor.authorScott I
dc.contributor.authorPomroy WE
dc.coverage.spatialNetherlands
dc.date.accessioned2024-11-06T01:43:26Z
dc.date.available2024-11-06T01:43:26Z
dc.date.issued2024-08-24
dc.description.abstractIn many regions of New Zealand liver fluke is endemic, infecting most grazing ruminants, including cattle, sheep, and deer. Restricting the economic losses and welfare costs associated with liver fluke relies on accurately identifying those animals with a production limiting infection. This has proven a difficult goal and although several antemortem quantitative tests are available, including faecal egg counts (FEC), serum ELISA and copro-antigen ELISA, none can be considered a gold standard test of liver fluke infection. The accepted gold standard test for fascioliasis is the total fluke count, which is both laborious and can only be completed at post-mortem. This study aimed to compare the performance of four liver fluke diagnostic tests, against the results of a gold standard total fluke count test. Two groups of cattle were selected, 29 culled mixed age beef cows (MAC) and ten 30-month-old steers. The cattle were blood sampled and faecal sampled prior to slaughter and their whole livers recovered post slaughter at the abattoir. Liveweight was also recorded at slaughter. After collection, each liver was weighed, scored for gross pathology, then serum, faeces and livers were frozen at -20 °C for later analysis. Faecal egg counts and F. hepatica copro-antigen ELISA tests were completed on the faecal samples and total fluke counts were completed on the livers. Fasciola hepatica antibody concentration in serum samples were quantified using a commercial ELISA test. Poisson regression models were built to model the association between each diagnostic test and the total fluke count, and a linear regression model was built to examine the relationship between each diagnostic test and live weight at slaughter. The median fluke count was significantly higher in MAC than steers (p = 0.01), and F. hepatica eggs were present in 100% steers and 66% MAC. There was a significant effect of copro-antigen ELISA value on total fluke count (p < 0.0001), with a coproantigen ELISA value = 20.1 predicting 10 flukes and a value = 44.8 predicting 30 flukes. There was also a significant effect of FEC on total fluke count (p = 0.002) but the R-squared value for this model was lower. There was no association between liver fibrosis score or antibody ELISA test and total fluke count (p = 0.95, p = 0.73, respectively). There was a significant effect of total fluke count (p = 0.03) on liveweight at slaughter, with liveweight falling 20.4 kg for each unit increase in loge (total fluke count). There was no effect of FEC (p = 0.11), antibody ELISA (p = 0.55) or copro-antigen ELISA value (p = 0.16) on liveweight at slaughter. Taken together, these results show that the coproantigen ELISA test is the better test for estimating the true liver fluke burden and that the number of flukes in the liver has a negative effect on cattle live weights at slaughter.
dc.description.confidentialfalse
dc.edition.editionSeptember 2024
dc.format.pagination101102-
dc.identifier.author-urlhttps://www.ncbi.nlm.nih.gov/pubmed/39237240
dc.identifier.citationDowling A, Lawrence KE, Howe L, Scott I, Pomroy WE. (2024). Assessment of accuracy of liver fluke diagnostic tests using the gold standard of total worm counts.. Vet Parasitol Reg Stud Reports. 54. (pp. 101102-).
dc.identifier.doi10.1016/j.vprsr.2024.101102
dc.identifier.eissn2405-9390
dc.identifier.elements-typejournal-article
dc.identifier.issn2405-9390
dc.identifier.number101102
dc.identifier.piiS2405-9390(24)00131-X
dc.identifier.urihttps://mro.massey.ac.nz/handle/10179/71929
dc.languageeng
dc.publisherElsevier B.V.
dc.publisher.urihttps://www.sciencedirect.com/science/article/pii/S240593902400131X
dc.relation.isPartOfVet Parasitol Reg Stud Reports
dc.rights(c) 2024 The Author/s
dc.rightsCC BY 4.0
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.subjectFasciola hepatica
dc.subjectGold standard test
dc.subjectNew Zealand
dc.subjectcattle
dc.subjectAnimals
dc.subjectCattle
dc.subjectFascioliasis
dc.subjectCattle Diseases
dc.subjectFeces
dc.subjectFasciola hepatica
dc.subjectParasite Egg Count
dc.subjectNew Zealand
dc.subjectMale
dc.subjectEnzyme-Linked Immunosorbent Assay
dc.subjectFemale
dc.subjectSensitivity and Specificity
dc.subjectLiver
dc.subjectDiagnostic Tests, Routine
dc.subjectAntibodies, Helminth
dc.titleAssessment of accuracy of liver fluke diagnostic tests using the gold standard of total worm counts.
dc.typeJournal article
pubs.elements-id491392
pubs.organisational-groupOther
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