Cyanobacteria and BMAA: Possible linkage with avian vacuolar myelinopathy (AVM) in the south-eastern United States

Avian vacuolar myelinopathy (AVM) is a neurological disease that produces uncoordinated behavior in affected birds in wetland ecosystems of the south-eastern United States. Feeding and sentinel trials, field surveys, and genetic studies have implicated the introduced flowering plant species Hydrilla verticillata (Hydrocharitaceae) and an associated epiphytic cyanobacterial species (Order Stigonematales) as a causal link to AVM. All five morphotypes of cyanobacteria have been shown to produce the neurotoxic amino acid BMAA, including cyanobacteria of the Stigonematales that are epiphytic on Hydrilla verticillata. If biomagnification of BMAA occurs in these wetland ecosystems, as has been observed in the Guam ecosystem, then the consumption of fish (e. g. shad and herring) and waterfowl (e. g. Canada geese and mallards) from AVM-confirmed reservoirs in Arkansas, Texas, Georgia, North Carolina and South Carolina could represent a significant human health risk.