“…A low mean lesion score was observed in T4 (2.5±0.22) followed by T2 (2.83±0.17), T1 (3.33±0.33) and T3 (3.00±0.45) in comparison with unimmunised infected T5 (3.33±0.33) thus indicating a partial protection (P>0.05) by the sporozoites. A similar observation was recorded by Ziomko et al, (2005) and Geriletu et al, (2011). Interferons have been reported to be inimical to parasites, probably because of their ability to inhibit parasite development (Lillihoj and Choi, 1998), promote production of free radicals (Dimier and Bout, 1997) and activate antibody-dependent cell-mediated cytotoxicity (Fleischer, 1980).…”