Cyanobacterial toxins and human health

The mass growths of cyanobacteria which develop in fresh, brackish and marine waters commonly contain potent toxins. At least 60 cyanobacterial toxins are now recognized. These include neurotoxic and hepatotoxic alkaloids, hepatotoxic peptides and lipopolysaccharide endotoxins. There exists a world-wide record of fatal poisonings, including those of domestic and wild animals, birds and fish. Although no reports of human death resulting from intoxication by cyanobacteria have been published, several cases implicating cyanobacterial toxins in human illness have been reported and these are reviewed. Further work providing laboratory evidence for the hazard of cyanobacterial toxins to human health is also discussed. Human illnesses can be attributed to cyanobacterial hepatotoxins and endotoxins, and are placed into three main categories: gastroenteritis and related diseases, allergic and irritation reactions, and liver diseases. The tumour-promoting actions of cyanobacterial hepatotoxins in laboratory studies – and the implications of these – are discussed with reference to epidemiological work in progress. The need for increased public awareness of the hazards of cyanobacterial toxins to human health is discussed, as are measures being taken to achieve this. Risk assessments of the acute risk of cyanobacterial hepatotoxins in drinking water have recently been carried out.