Deciphering the infection biology of avian pathogenic Escherichia coli: role of experimental infection models

Avian pathogenic Escherichia coli (APEC) is a well-recognised pathotype that causes localised and systemic infections in avian species of all ages including eggs. To develop successful intervention strategies, a deep understanding of bacterial and host factors mediating crucial processes in pathogenesis is required. Such information can only be gathered through approaches that embrace infection models using the target hosts. Existing infection models for APEC include: intratracheal inoculation, intra-airsac inoculation, intravenous injection, intraperitoneal inoculation, intranasal inoculation, aerosol exposure, subcutaneous injection, intramuscular injection and intra-allantoic inoculation. Describing these models in detail, this chapter highlights salient information on how each of these infection models has contributed to our understanding of the pathogenesis, host responses and testing of control methods for APEC infections.