IREB2 and infection: The pathogenicity of E. coli is the result of the synergistic effect of multiple virulence factors, and some studies have shown that E. coli of tiger origin has a variety of virulence factors, including Stx2f, fimC, cnf-1, fyuA, iroc, irp2, etc., which may be related to the severity of the infection and the course of the disease may also be an important cause of the disease (Zhang, 2022).