Current genetic tools available for monitoring and identifying cyanobacterial HABs focus on the DNA sequences of particular genes in the cyanobacterial genomes. The surest way to deduce toxigenicity is to look for the presence of toxin biosynthetic genes, and exciting advances in recent years have made this possible for each of the major toxins (microcystin, anatoxin-a, cylindrospermopsin, saxitoxin).
The most common human exposure to cyanotoxins is during recreational activities on water bodies with ongoing cyanoHABs. Studies found that persons who were exposed to waters with concentrations of cyanobacteria >5,000 cells/mL during recreational activities were more likely to report at least one symptom during the week following exposure than were persons exposed to waters that did not contain cyanobacteria.
