Table 7.

Available liver fluke diagnostic techniques, when to use them and their characteristics (valid for western Europe)

Test	When to use it	Sampling	Diagnostic value	Drawbacks
Blood antibody ELISA	From approx. 3–4 weeks post-infection	Regular blood sampling. Use first-season grazing animals (lambs and/or calves) as “sentinels” and 10 animals per risk group (consider on-farm risks, such as grazing)	Measure of acute disease risk. Increasing antibody levels identify when active infection is occurring for targeted treatment	Careful interpretation of test results is required to avoid premature treatment. Test results for sentinel animals indicate risk status only for their group. Antibody levels can remain high even after successful treatment and in previously exposed older animals
Coproantigen ELISA	From approx. 8–10 weeks post-infection	Dung, individual (avoid using pooled if possible)	Mid- to late-stage infection	Low sensitivity in cattle and in pooled samples. If result is negative, advise re-test in approx. 4 weeks
Milk ELISA	From approx. 2–4 weeks post-infection	Bulk milk tank	Monitoring the parasite-infection status of a herd Test results are associated with parasite-induced production losses	Antibodies can persist until 8 months after effective treatment
Fluke egg counts	From approx. 10–11 weeks post-infection	Dung, individual and pooled	Definitive diagnosis when adult parasites present	Test sensitivity may be low, especially in cattle. If result is negative, advise re-test in 4–8 weeks
Post-mortem	From approx. 2 weeks post-infection	Fallen stock	Definitive diagnosis (all stages of infection)	Abattoir returns are useful, but should not be considered equivalent to veterinary post-mortem in terms of reliability

ELISA Enzyme-linked immunosorbent assay

Adapted from: Liver fluke. A guide to test-based control [94]