To assess cellular immune response, 10.5% (2/19) of the studies that performed experimental infection used the Enzyme‐linked immunosorbent assay (ELISA) and 57.9% (11/19) used RT‐qPCR to evaluate cytokines such as IL‐10, IFN‐γ and IL‐4 in materials such as animal serum and cell culture supernatant. This evidence concerns the gene IL4 and infection.