Antibody detection against Kunitz-type protein in Fasciola hepatica experimentally infected sheep using enzyme-linked immunosorbent assay (ELISA)

Abstract
Fasciolosis is a parasitic disease considered as emerging and neglected by the WHO. Sheep are highly susceptible to this disease, and affected flocks experience decreased productivity due to increased mortality and reduced quality of their products such as wool and meat. To effectively control this disease, reliable and early diagnosis is essential for making decisions regarding the application of antiparasitics and/or the removal of affected animals.
The current diagnosis of F. hepatica in sheep relies on the detection of parasite eggs in feces, a method that becomes reliable from week 10 post-infection. Consequently, there is a need for earlier diagnostic tools based on immune response. However, the obtaining of antigens for antibody detection has proven to be difficult and expensive.
In this study, we compared the performance of recombinant F. hepatica Kunitz-type inhibitors (FhKT1.1, FhKT1.3, and FhKT4) in sera from experimentally F. hepatica-infected sheep six weeks post-infection with a synthetic Kunitz-type peptide (sFhKT) used as antigens by ELISA. Among these, FhKT1.1 showed the most promising diagnostic indicators, exhibiting high precision and low cross-reactivity, thus holding potential for standardized production.
The results of our study demonstrated that the application of FhKT1.1 is a valuable tool for early-stage diagnosis of F. hepatica in sheep. Such an early diagnosis can aid in implementing timely interventions and effectively managing the disease in sheep populations