GANGLIOSIDOSIS IN EMUS (DROMAIUS-NOVAEHOLLANDIAE)

A 6-month-old female emu (Dromaius novaebollandiae) died following acu te central nervous system signs. Hematoxylin-and-eosin-stained section s revealed that neurons of the brain were distended with nonstaining 1 -to-2-mu m vacuoles. Ultrastructural examination of the affected neuro ns revealed numerous membranous cytoplasmic bodies (MCBs) similar in a ppearance to the MCBs seen in mammalian gangliosidoses. A full sibling of this emu was donated for study. This 7-month-old female emu was st unted compared with hatchmates. Neurologic examination revealed hyperm etric gait, persistent head tremor and mild ataxia. No gross lesions w ere evident at postmortem. Histopathologic and electron microscopic fi ndings were similar to those in the index case in that swollen, pale n eurons were present in the cerebrum, pons, medulla, cerebellum, spinal cord, spinal ganglia, autonomic ganglia, myenteric plexus, and gangli on cell layer of the retina. Analysis of brain gangliosides of the aff ected 7-month-old emu revealed 14- and 25-fold increases of GM1 and GM 3 gangliosides, respectively, compared with control emus. The total br ain ganglioside sialic acids were, on a wet weight basis, 519 mu g/g ( control A), 658 mu g/g (control B), and 1800 mu g/g (affected emu). Th e familial association seen with this condition suggests that emus are affected by an inherited disorder similar to mammalian gangliosidoses .