Prevalence of liver fluke (Fasciola hepatica) in wild Red Deer (Cervus elaphus): coproantigen ELISA is a practicable alternative to faecal egg counting for surveillance in remote populations

French, A. S., Zadoks, R. N. , Skuce, P. J., Mitchell, G., Gordon-Gibbs, D. K., Craine, A., Shaw, D., Gibb, S. W. and Taggart, M. A. (2016) Prevalence of liver fluke (Fasciola hepatica) in wild Red Deer (Cervus elaphus): coproantigen ELISA is a practicable alternative to faecal egg counting for surveillance in remote populations. PLoS ONE, 11(9), e0162420. (doi: 10.1371/journal.pone.0162420) (PMID:27598003) (PMCID:PMC5012657)

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Abstract

Red deer (Cervus elaphus) are hosts of liver fluke (Fasciola hepatica); yet, prevalence is rarely quantified in wild populations. Testing fresh samples from remote regions by faecal examination (FE) can be logistically challenging; hence, we appraise frozen storage and the use of a coproantigen ELISA (cELISA) for F. hepatica surveillance. We also present cELISA surveillance data for red deer from the Highlands of Scotland. Diagnoses in faecal samples (207 frozen, 146 fresh) were compared using a cELISA and by FE. For each storage method (frozen or fresh), agreement between the two diagnostics was estimated at individual and population levels, where population prevalence was stratified into cohorts (e.g., by sampling location). To approximate sensitivity and specificity, 65 post-slaughter whole liver examinations were used as a reference. At the individual level, FE and cELISA diagnoses agreed moderately (κfrozen = 0.46; κfresh = 0.51), a likely reflection of their underlying principles. At the population level, FE and cELISA cohort prevalence correlated strongly (Pearson’s R = 0.89, p < 0.0001), reflecting good agreement on relative differences between cohort prevalence. In frozen samples, prevalence by cELISA exceeded FE overall (42.8% vs. 25.8%) and in 9/12 cohorts, alluding to differences in sensitivity; though, in fresh samples, no significant difference was found. In 959 deer tested by cELISA across the Scottish Highlands, infection prevalence ranged from 9.6% to 53% by sampling location. We highlight two key advantages of cELISA over FE: i) the ability to store samples long term (frozen) without apparent loss in diagnostic power; and ii) reduced labour and the ability to process large batches. Further evaluation of cELISA sensitivity in red deer, where a range of fluke burdens can be obtained, is desirable. In the interim, the cELISA is a practicable diagnostic for F. hepatica surveillance in red deer, and its application here has revealed considerable geographic, temporal, sex and age related differences in F. hepatica prevalence in wild Scottish Highland red deer.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Zadoks, Professor Ruth and Skuce, Dr Philip
Authors: French, A. S., Zadoks, R. N., Skuce, P. J., Mitchell, G., Gordon-Gibbs, D. K., Craine, A., Shaw, D., Gibb, S. W., and Taggart, M. A.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:PLoS ONE
Publisher:Public Library of Science
ISSN:1932-6203
ISSN (Online):1932-6203
Copyright Holders:Copyright © 2016 French et al.
First Published:First published in PLoS ONE 11(9): e0162420
Publisher Policy:Reproduced under a Creative Commons License

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