Abstract
-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.