Comparative study of clinical examinations, necropsy findings, and X-ray signs in naturally infected pigeons to avian tuberculosis

<i>Mycobacterium avium</i> subsp. <i>avium</i> is the primqry cause of avian tuberculosis, a chronic disease affecting many bird species. Depending on the infected organs, the clinical manifestations of the disease are usually nonspecific and variable. The growing risk of the disease spreading to the humans has made diagnosing it in birds more important. Therefore, the present study investigated avian tuberculosis infection in several domestic pigeon's lofts in Markazi Province, Iran. Twelve pigeons from different suspected pigeon lofts were collected, fed properly, and kept under suitable conditions. After recording clinical manifestations, athe pigeons underwent radiographic imaging in lateral and ventrodorsal positions. Then, the pigeons were euthanized and subjected to necropsy examinations. During necropsy examinations, samples taken from any visible lesions. If no lesions were present, samples were taken from the liver and delivered to the tuberculosis reference laboratory for culturing in LJG, LJP, H, and HM culture media. Finally, the grown colonies were tested using Polymerase Chain Reaction (PCR) with the primers targeting 16S rRNA, IS1245, and IS901. The most prominent clinical manifestations in the infected pigeons were cachexia and articular swelling of the wings and legs, while the most common radiographic findings were periarticular inflammation and Renomegaly. Moreover, nodules and lesions in the liver, the gastrointestinal tract, and the abdominal cavity were the most prevalent in the necropsy findings. Culture, Ziehl-Neelsen staining results, and PCR test results confirmed that all 12 pigeons were infected with Mycobacterium. <i>avium</i> subsp. <i>avium</i>. Also, the radiographic and necropsy findings demonstrated the destructive effects of avian tuberculosis on the infected pigeons.