Pathological studies on natural cases of avian colibacillosis in Haryana state.

Abstract

Pathological studies were undertaken on natural cases of poultry carcasses to study the incidence and pathological lesions of Escherichia coli infection. Colibacillosis was noticed in different age groups but maximum mortality was evident in birds of 3-4 weeks of age. E. coli was isolated from blood and liver samples in 86.6% cases. Gross pathological changes included congestion in various organs, accumulation of fibrin on the liver and heart. Histopathologically there was fibrinous pericarditis, myocarditis, fibrinous perihepatitis, hepatitis and fatty changes in hepatocytes, interstitial pneumonia, necrosis and depletion of lymphocytes in spleen and enteritis. It is concluded that pathogenic E. coli in natural cases caused systemic lesions in chicks and also resulted in immunosuppression. During last few decades, intensive rearing has become a method of poultry husbandry that has predisposed birds for various infectious diseases and thus poultry industry has suffered great losses. Escherichia coli is a commensal organism residing in the intestinal tract of poultry, and often turns pathogenic under adverse conditions. Colibacillosis is a complex syndrome characterized by multiple organ lesions like air-sacculitis, pericarditis, peritonitis, salpingitis, synovitis, osteomyelitis or yolk sac infection. Avian pathogenic E. coli (APEC) causes significant morbidity and mortality leading to multimillion-dollar losses to poultry industry (Barnes, 2008). The present study was undertaken to elucidate pathological lesions in field cases of E. coli infected broiler chicks. The investigation on the field cases included postmortem examination, isolation of E. coli organism and histopathology.