Avian pathogenic Escherichia coli: Epidemiology, virulence and pathogenesis, diagnosis, pathophysiology, transmission, vaccination, and control

Avian pathogenic Escherichia coli (APEC) causes colibacillosis in poultry; this type of bacteria is an extraintestinal pathogen E. coli. Unlike other E. coli pathogen groups, the characteristics of APECs cannot be identified by a single group. Serotyping and biotyping are frequently performed for isolates found in colibacillosis infections. The establishment, transmission, and persistence of this pathogenic strain in chicken populations are determined by the intricate interactions of multiple elements that make up the epidemiology of APEC. APEC employs many virulence and pathogenesis factors or mechanisms to infect chickens with colibacillosis. These factors include invasives, protectins, adhesins, iron acquisition, and toxins. In addition, the pathogenicity of APEC strains can be evaluated in 2–4 week-old chicks. The impact of unfavorable environmental conditions has also been documented, despite direct contact being demonstrated to be a significant element in transmission in APEC. Chickens are immunized against colibacillosis using a variety of vaccines. Nevertheless, commercially available vaccinations do not offer sufficient immunity to protect birds from APEC strains. Hatching egg contamination is one of the main ways that APECs spread throughout chicken flocks. Farmers also need to be mindful of storing discarded materials near the manure-watering area, removing them when necessary, and replacing wet materials with dry materials when needed. This review aimed to explain the characteristics, epidemiology, virulence, pathogenesis, diagnosis, pathophysiology, transmission, vaccination, and control of APEC.