ABSTRACT
In freshwater, harmful algal blooms are mostly attributed to cyanobacteria (blue-green algae). The main types of toxins produced by cyanobacteria are hepatotoxins and neurotoxins. Three types of cyanobacterial neurotoxins are known: (homo)anatoxin-a, anatoxin-a(S) and saxitoxins (also called paralytic shellfish poisons, PSPs). Mass occurrences of neurotoxic cyanobacteria have been reported from America, Europe, and Australia where they have caused numerous animal poisonings. (Tables 1 and 2). Interestingly, in Australia, only saxitoxins are common; anatoxins have not been found. In Europe and America, the occurrence of all three types of cyanobacterial neurotoxins have been reported. Recent chemical analysis has shown anatoxin-a also to occur in freshwater in Asia (North Korea and Japan). Furthermore, it is obvious that neurotoxins are produced not only by planktic cyanobacteria but also by benthic mat-forming species (18, 23).
