Mycobacterium avium avium Causing Conjunctivitis in a Cockatiel (Nymphicus hollandicus)

Avian mycobacteriosis, caused by Mycobacterium avium avium, presents a significant concern in both wild and domestic bird populations, including pet birds and poultry, with zoonotic potential. This article discusses the case of conjunctival mycobacteriosis in a cockatiel, a rare manifestation of the disease. A 5-year-old male cockatiel presented with a protuberance on its right lower eyelid, which upon biopsy revealed necrotic eosinophilic follicles surrounded by multinucleated giant cells and an inflammatory cell infiltrate. Ziehl-Neelsen staining confirmed the presence of acid-fast rod-shaped bacteria within phagocytic cells, indicative of Mycobacterium avium avium infection. PCR assay targeting the rpoB gene further confirmed the species identification. Phylogenetic analysis showed high sequence similarity with human isolates. This case underscores the importance of considering mycobacteriosis in birds with granulomatous conjunctivitis and highlights the complexity of diagnosis, emphasizing the utility of histological examination alongside molecular techniques for accurate identification. Detection of mycobacterial infection in avian species is crucial both for veterinary and public health perspectives, given the zoonotic potential of these pathogens.