The observed upregulation in the expression pattern of the pro-inflammatory cytokine (IFN-γ) in the infected Nile tilapia was in line with the findings of Moustafa et al. [98], who demonstrated upregulation in the expression of pro-inflammatory immune response-related genes (TNF-α and IL-1β) following infection with A. hydrophila. The gene discussed is IL1B; the disease is infection.