Evaluation of Fas2-ELISA in milk and serum for the detection of Fasciola hepatica infection in cattle

Fasciola hepatica causes a significant loss in milk and meat production in cattle farming worldwide. The treatment and control of F. hepatica infection in cattle raised in regions with a high prevalence of the infection requires sensitive, specific, and affordable diagnostic tests. This study aims to evaluate two tests, Fas2-ELISA and ES-ELISA, for the diagnosis of fascioliasis in beef and dairy cattle from two livestock basins in Peru. Serum and fecal samples were collected from beef cattle slaughtered at an abattoir in Lima; serum, milk, and fecal samples were collected from F. hepatica naturally infected dairy cows in the San Lorenzo district, located in the Mantaro Andean Valley, and dairy cows raised in university stables in La Molina district in Lima. ES-ELISA detects IgG antibodies against F. hepatica excretory-secretory products (ES) from adult flukes, and Fas2-ELISA detects the Fas2 antigen, a cysteine proteinase purified from F. hepatica adult flukes. The diagnostic parameters for beef cattle were determined using inspection for F. hepatica flukes in the liver as a reference test. ES-ELISA for the detection of F. hepatica infection in beef cattle showed a sensitivity (Se) of 93.2 % (95 % CI, 83.5–98.1 %) and specificity (Sp) of 88 % (95 % CI, 80.4–93.5 %). Fas2-ELISA showed a Se and Sp of 98.3 % (95 % CI, 91–99 %) and 93.6 % (95 % CI, 87–97 %), respectively. The diagnostic parameters for detecting F. hepatica infection in milk samples by ES-ELISA showed a Se of 100 % (95 % CI, 92–100 %) and Sp of 83 % (95 % CI, 65–94 %), Fas2-ELISA showed a Se of 98 % (95 % CI, 89–100 %) and Sp of 93 % (95 % CI, 78–99 %) using coproscopy as a reference test. These results suggest that Fas2-ELISA could be a useful test for detecting F. hepatica infection in milk samples from dairy cattle and may be further developed as a bulk-tank milk (BTM) test to estimate the prevalence of F. hepatica infection in dairy herds.