Cyanobacteria, neurotoxins and water resources: Are there implications for human neurodegenerative disease?

Abstract

Cyanobacteria are cosmopolitan microbes that inhabit marine, freshwater and terrestrial environments. Under favourable conditions in waterbodies, they can form massive populations (blooms and scums), which present hazards to human and animal health. Such cyanobacteria often contain a variety of toxic substances (cyanotoxins) that can exist as both cell-associated and free forms in the surrounding water. Some cyanotoxins are highly neurotoxic and act through a variety of mechanisms. Recent findings of the production of the neurotoxin β-N-methylamino-L-alanine (BMAA) by cyanobacteria in aquatic environments, and of BMAA in brain and cerebrospinal fluid samples of amyotrophic lateral sclerosis and Alzheimer's disease victims, raises the possibility that people may be exposed to waterborne BMAA of cyanobacterial origin and that this may contribute to human neurodegenerative disease. An understanding of the risks presented by waterborne BMAA and of available mitigation strategies to reduce this potential exposure is needed.

Key words::

• Cyanobacteria
• neurotoxins
• water resources
• neurodegeneration
• BMAA

Acknowledgements

We thank the following for research support and collaboration: the UK Natural Environment Research Council, the European Union and the Institute for Ethnomedicine.

Declaration of interest: The authors report no conflicts of interest and alone are responsible for the content and writing of this paper