Evaluation of alum-adjuvanted Fasciola gigantica recombinant pro-cathepsin L1H as a potential vaccine for goats.

The present study was conducted to evaluate the immunoprophylactic potential of Fasciola gigantica recombinant pro-cathepsin L1H (rproFgCatL1H), formulated with Al(OH)3 adjuvant, in goats subsequently challenged with the parasites. Twenty-four goats were randomly assigned to four groups as follows: (I) uninfected, unimmunized controls (n = 6); (II) infected, unimmunized controls (n = 5); (III) infected, adjuvant control (aluminum hydroxide gel only, n = 6); and (IV) infected, vaccinated group receiving 100 µg rproFgCatL1H formulated with aluminum hydroxide gel (n = 7). Immunization with 100 µg of rproFgCatL1H conferred a statistically significant reduction in worm recovery compared with both the infected control and adjuvant control groups, corresponding to reductions of 35.99% and 26.59%, respectively (p < 0.05). Despite the absence of statistically significant differences in parasite morphometry, worms recovered from vaccinated animals exhibited a consistent tendency toward reduced mean wet weight. Scanning electron microscopy (SEM) analysis of adult F. gigantica recovered from vaccinated goats revealed pronounced tegumental damage, characterized by extensive swelling, surface furrowing, erosion, and the presence of cell-like structures adhering to the tegumental surface. Collectively, these findings indicate that alum-adjuvanted rproFgCatL1H represents a promising vaccine candidate for the control of fasciolosis in goats.