Zhao et al. (2014) found an increase in IL-17 mRNA levels within 12 h pi in chickens, and a study of C. parvum in mice found that within 6 h pi IL-17 mRNA was upregulated in the intestine and within 24 h in the spleen (Zhao et al., 2016). These studies clearly suggest that IL-17 signalling is rapidly upregulated early in infection. Herein we sought to examine the dynamics of early C. parvum infection in a bovine gut model. Here, IL17A is linked to infection.