Lafora Disease and Alpha-Synucleinopathy in Two Adult Free-Ranging Moose (Alces alces) Presenting with Signs of Blindness and Circling
Animal Health and Assurance, Alberta Agriculture, Forestry and Rural Economic Development, Edmonton, AB T6H 4P2, Canada
Department Laboratory Medicine and Pathology at Alberta Precision Laboratories, University of Alberta, Edmonton, AB T6G 2R3, Canada
Fish and Wildlife, Alberta Environment and Parks, Edmonton, AB T6H 4P2, Canada
Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
Author to whom correspondence should be addressed.
Current address: Charles River Laboratories, Laval, QC H7V 4B3, Canada.
Academic Editor: Rita Tinoco Torres
Received: 30 May 2022
Revised: 16 June 2022
Accepted: 20 June 2022
Published: 25 June 2022
Reports of behavioral signs, such as blindness and circling in free-ranging moose from different parts of the world, have spurred comprehensive pathological investigation to find the causes of the disease that have clinical relevance. In this case study, brains collected from two adult free-ranging moose (Alces alces) cows that were seemingly blind and found walking in circles were examined by light and electron microscopy with further ancillary testing. Here, we report for the first time Lafora disease and alpha-synucleinopathy in two wild free-ranging moose cows who presented with abnormal behavior and blindness, with similar neuronal polyglucosan body (PGB) accumulations identified in humans and other animals. Microscopic analysis of the hippocampus of brain revealed inclusion bodies resembling PGBs (Lafora disease) in the neurons with ultrastructural findings of aggregates of branching filaments, consistent with polyglucosan bodies. Furthermore, α-synuclein immunopositivity was noted in the hippocampus, with accumulations of small granules ultrastructurally distinct from PGBs and morphologically compatible with alpha-synucleinopathy (Lewy body). The apparent blindness found in these moose could be related to an injury associated with secondary bacterial invasion; however, an accumulation of neurotoxicants (PGBs and α-synucleins) in retinal ganglion cells could also be the cause. Lafora disease and alpha-synucleinopathy were considered in the differential diagnosis of the young adult moose who presented with signs of blindness and behavioral signs such as circling.