Impact of <scp> <i>Fasciola hepatica</i> </scp> Infection and Triclabendazole Treatment on Humoral Immune Response in Cattle

Fasciola hepatica is a trematode parasite of significant veterinary and public health importance, causing economic losses in livestock due to liver damage, weight loss and reduced milk production. Although triclabendazole (TCZ) is available for treatment, it does not prevent the disease or reinfection. Infected animals exhibit strong immunoregulation, increasing susceptibility to secondary infections and altering vaccine-induced antibody responses. This study investigates the humoral immune response in cattle infected with F. hepatica at different stages of infection and evaluates the effect of TCZ treatment on this response. It also examines how fasciolosis affects the antibody response induced by bacterial vaccines during early and chronic infection stages. Experimental infections in steers were conducted, with faecal and plasma samples collected at various intervals. The results showed a decrease in parasite-specific antibody avidity during infection. However, F. hepatica infection did not substantially modify antibody response to bacterial vaccines. This study underscores the need for further research on the impact of fasciolosis and its treatment on livestock vaccination efficacy.