Pathological investigations on an outbreak of avian Tuberculosis (AvTB) in a Turkey flock in Dhaka

A flock of four-week old turkey chicks showed clinical signssuch as fatigue, in-appetence, gasping and eventual death after having a very brief illnesses. Postmortem examinations showed non-mineralized elevated nodules in the lung, costal membranes and inner surface of the abdominal cavity. Histopathologic findings were typical of avian tuberculosis, with necrotic debris in the lung parenchyma. The lesions were found to be surrounded by epithelioid macrophages, lymphocytes, and multinucleated giant cells. Laboratory confirmation was made based on lesions and using Ziehl-Neelsen(ZN) acid-fast stain. The presence of granulomas in the lungs of the infected chicks may suggest that the exposure to the infective agent was via the respiratory route rather than the alimentary route. The case was diagnosed as tuberculus peri-bronchial pneumonia.