Presumed mycobacteriosis in laboratory zebra finch (Taeniopygia guttata)

Abstract

Husbandry staff noticed a research-naïve, young-adult, female finch tossing its head back intermittently. A second finch exhibiting similar signs was reported a few days later. Postmortem necropsy and histopathology with hematoxylin and eosin and acid-fast staining on the first finch revealed the presence of acid-fast organisms in several organs. After presumptive diagnosis of mycobacteriosis, all remaining finches housed in the same room as the first underwent necropsy and histology. Three additional finches were positive for Mycobacterium-like acid-fast organisms. Incidental findings of megabacteriosis were noted histopathologically on 2 other finches.

Figure 1.

Section of duodenum with many large swollen macrophages in the lamina propria. The abundance of macrophages caused thickening of the lamina propria of the villi in this section (arrowss). Hematoxylin and eosin stain; bar, 25 µm.

Figure 2.

Acid-fast staining of this section of duodenum revealed numerous intracellular, slender, rod-shaped, acid-fast–positive bacteria in the cytoplasm of the macrophages in the duodenum (arrows). Ziehl–Neelsen stain; bar, 50 µm.

Figure 3.

The lungs were severely affected with a macrophage infiltrate similar to that in the duodenum and often oriented around the parabronchi (arrows). Some of these macrophages also contained deposits of brown-black material, as often can be seen with pneumoconiosis. Hematoxylin and eosin stain; bar, 25 µm.

Figure 4.

Acid-fast staining of this section of lung revealed numerous intracellular, slender, rod-shaped, acid-fast–positive bacteria in the cytoplasm of macrophages (arrows). Ziehl–Neelsen stain; bar, 25 µm.