Avian Mycobacteriosis Study Guide

Overview and Clinical Importance

Avian mycobacteriosis (often incorrectly termed "avian tuberculosis") is a chronic, progressive, granulomatous disease affecting companion, captive exotic, wild, and domestic birds worldwide. This disease is caused by non-tuberculous mycobacteria (NTM), most commonly Mycobacterium avium subsp. avium (MAA) and Mycobacterium genavense. The condition is characterized by insidious onset, prolonged disease course, poor prognosis, and significant zoonotic potential, particularly for immunocompromised individuals.

Mycobacteriosis represents a World Organization for Animal Health (WOAH) List B disease due to its socio-economic and public health significance. Understanding this disease is essential for NAVLE success, as questions frequently focus on species predisposition, clinical presentation, diagnostic approaches, zoonotic considerations, and the challenging decision between treatment and euthanasia.

Etiology and Causative Agents

Mycobacteria are acid-fast, Gram-positive, slow-growing, aerobic bacilli characterized by a waxy, lipid-rich cell wall containing mycolic acids. This unique cell wall structure confers resistance to conventional staining (requiring Ziehl-Neelsen or Fite-Faraco stains), environmental persistence, and resistance to many antimicrobials.