Epsilon Archive for Student Projects

Abstract

Fasciolosis, caused by the liver fluke Fasciola hepatica, is a parasitic disease of major economic importance in cattle and sheep production worldwide. Accurate diagnosis is essential for effective control, yet the performance of available diagnostic methods varies considerably depending on infection intensity, host species, and practical circumstances.
This master's thesis compared three methods: i) traditional sedimentation, ii) AI-based copromicroscopy (OvaCyte™), and iii) a commercial coproantigen-ELISA test, for diagnosing F. hepatica in faecal samples of ruminants.
A total of 70 faecal samples were collected from livestock (47 from cattle and 23 from sheep) at four locations in Sweden. For 28 cattle and 23 sheep that were sampled at slaughter, infection status was first determined through visual liver inspection. Faecal samples were then analysed using all three methods. Detection rates, egg counts, coinfection with rumem fluke , time efficiency, and agreement between the different methods were evaluated.
Coproantigen-ELISA detected F. hepatica in the highest proportion of tested samples (49/70, 70.0%), followed by traditional sedimentation (45/70, 64.3%) and OvaCyte™ (37/70, 52.9%). In sheep, all three methods detected F. hepatica in all 23 samples (100%). In cattle, ELISA was positive in 26 of 47 samples (55.3%) , sedimentation in 22 of 47 samples (46.8%) , and OvaCyte™ in 14 of 47 samples (29.8%). OvaCyte™ recovered the highest total number of F. hepatica eggs (1,261 EPG) compared to sedimentation (1,146 eggs/5g). Rumen fluke infection was common in sheep (73.9% by sedimentation, 60.9% by OvaCyte™) but rare in cattle (2.1–4.3%). ELISA was the most time-efficient method (6 hours for 70 samples), followed by OvaCyte™ (12 to 15 minutes preparation plus 3 minutes reading time per sample) and sedimentation (45 minutes sedimentation plus 11 to 16 minutes reading time per sample). Pairwise agreement between methods was moderate (κ = 0.44–0.47), with the highest agreement observed between the microscopy-based detection methods.
No single diagnostic method is optimal for all situations. ELISA is most effective for herd level screening and early detection in cattle. Sedimentation remains a practical, low cost alternative for confirmatory diagnosis, particularly in resource limited settings. OvaCyte™ provides full automation, consistent results, and excellent performance in sheep, along with the unique ability to detect mixed infections with rumen flukes simultaneously. In sheep, OvaCyte™ is the preferred method due to its perfect detection rate, highest egg recovery, and ability to detect mixed infections with other flukes. For mixed farms, ELISA is recommended for cattle, but it is also suitable for sheep. When clinical suspicion is high or the consequences of missing an infection are severe, using multiple tests in parallel provides the most reliable diagnosis.