In addition, the levels of proinflammatory cytokines in serum, such as IL-17A, IL-6, IFN-γ and TNF-α, were significantly increased post-infection (t(28) = -2.852, P = 0.040; t(28) = -3.655, P = 0.036 and t(28) = -9.704, P = 0.001 and t(28) = -2.876, P = 0.039, respectively) (Fig. 2c). Here, IL6 is linked to infection.