IL6 and infection: The current study was designed to (1) determine E. coli prevalence in diseased broiler chickens; (2) describe impacts of infection by different serotypes of E. coli clinical signs, mortalities, macroscopic lesions, and histopathology; (3) and identify the effects of infection by different serotypes on IL gene expression (IL-6, IL-8, and IL-10) in broiler chickens using reverse transcription-quantitative PCR (RT-qPCR).