Abstract
BackgroundFasciola hepatica is a liver parasite of mammals and it results in poor welfare outcomes and economic losses in ruminants. While faecal egg count is the test most commonly used for diagnosis, it does not indicate presence of migrating immature stages. Serological techniques increase sensitivity at all stages of the liver fluke infection. The aim of this study was to compare four commercially available ELISA tests for the diagnosis of F. hepatica. For this purpose, we tested three sample types; (i) known F. hepatica status sera from an experimental infection for the comparison of sensitivities and specificities, (ii) sera from pre- and post-flukicide-treated (albendazole, closantel, nitroxynil and triclabendazole) beef cattle to contrast the differences of seropositivity before and after treatment, and (iii) bulk tank milk samples from dairy herds sampled during high and low F. hepatica exposure periods for assessing seasonal variations with the four tests available. Samples were tested using ELISA kits supplied by four manufacturers (Ildana Biotech, IDEXX, Svanova, and Bio-X). Samples were analysed simultaneously and in duplicate.ResultsIn the control population Ildana, IDEXX and Bio-X presented 100% sensitivity (Se) and specificity (Sp), Svanovir presented a Se of 59% and a Sp of 96%. In flukicide-treated beef cattle, kits highlighted decreasing antibody levels 90 days post-treatment in variable degrees. Finally, bulk milk showed a significant decrease in ELISA value between high and low fluke exposure periods with all tests studied.ConclusionsSe and Sp found in the present study, confirm that Ildana, IDEXX and Bio-X are accurate for the detection of F. hepatica exposure in Irish cattle. Svanovir Se and Sp in this population, indicate that a larger study is necessary to confirm this test characteristic in Irish herds. In post-treatment use, Bio-X showed a consistent and significant decrease of ELISA value in all groups treated, denoting to be a reliable tool for assessing treatment effect at 90 days post-treatment. Finally, all tests showed to be a reliable tool for the F. hepatica monitoring of high and low exposure seasons, using bulk tank milk samples.
Highlights
Fasciola hepatica is a liver parasite of mammals and it results in poor welfare outcomes and economic losses in ruminants
With regards to the Bio-X kit, containing the CL1 antigen (Table 1), an earlier study found a strong correlation between an inhouse enzyme-linked immunosorbent assays (ELISA), which used the same antigen as Svanovir (E/S), and Bio-X in sera from non-infected and naturally infected cattle [46]
The Svanovir kit has previously shown a significant decrease of optical density ratio (ODR) at 3–6 months [49] and 1 year [50] post treatment. These previous reports and the present results propose the use of the Svanovir kit more than 90 days after treatment
Summary
Fasciola hepatica is a liver parasite of mammals and it results in poor welfare outcomes and economic losses in ruminants. Fasciola hepatica has a preference for temperate climatic zones as its 18 to 30 week life cycle [4] requires mild temperatures and high humidity for the development of the intermediate host and free-living stages [15,16,17,18]. It can, be found in areas of the tropics in conjunction with Fasciola gigantica [14]. In temperate climatic zones without large seasonal climatic variations such as Ireland, management factors strongly influence the exposure and spatial distribution of the parasite [20, 21]
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