Histopathological Diagnosis and Detection of <i>Avian Pathogenic Escherichia Coli</i> Virulence Genes in Broiler Chickens in Indonesia.

Colibacillosis is a disease in poultry that often occurs in poultry farms in developing countries, including Indonesia. This disease is generally caused by cage or environmental sanitation problems, as well as poor poultry husbandry patterns. Colibacillosis, caused by <i>Avian Pathogenic Escherichia coli</i> (APEC) infection, is one of the significant health problems in the poultry industry, especially in Indonesia, with clinical symptoms such as emaciation decreased appetite, impaired growth, diarrhea, dirty or sticky feathers around the vent, bloated intestines ,and white feces. This study aims to V histopathological identification and detect virulence genes of Avian pathogenic <i>Escherichia coli</i> in broiler chickens. The methods used included organ sampling such as heart, liver, jejunum ,and cecum, which were then processed for histopathological preparation using Hematoxylin-Eosin (HE) staining. In addition, molecular diagnosis was performed using <i>Polymerase Chain Reaction</i> (PCR) technique to detect virulence genes, <i>iroN</i> and <i>hlyF</i>. The results showed that avian pathogenic <i>Escherichia coli</i> isolates were present in chickens suspected of colibacillosis, with positive blood agar culture showing hemolysin production (β-hemolysis), and the gene encoding <i>hlyF</i> was found positive but the gene encoding iroN was not. Histopathology results of liver, heart, jejunum ,and cecum infected with pathogenic <i>Escherichia coli</i> showed damage in the form of hemorrhage, necrosis, rupture of intestinal villi, erythrocyte accumulation, central venous congestion, and fatty degeneration. Our study demonstrates that <i>avian pathogenic</i> <i>Escherichia coli</i> strains can be isolated from broiler chickens suffering from colibacillosis and cause anatomical pathological changes. This study emphasizes the importance of a better understanding of this pathogen to develop effective prevention and control strategies in the poultry farming industry.