Toxicology of microcystins with reference to cases of human intoxications and epidemiological investigations of exposures to cyanobacteria and cyanotoxins

Abstract

Blooms of cyanobacteria have been documented throughout history, all over the world. Mass populations of these organisms typically present hazards to human health and are known for the production of a wide range of highly toxic metabolites-cyanotoxins, of which among the most common and most investigated are the microcystins. The toxicity of the family of microcystin congeners to animal and cell models has received much attention; however, less is known about their negative effects on human health, whether via acute or chronic exposure. Useful information may be acquired through epidemiological studies since they can contribute to knowledge of the relationships between cyanotoxins and human health in environmental settings. The aim of this review is to compile and evaluate the available published reports and epidemiological investigations of human health incidents associated with exposure to mass populations of cyanobacteria from throughout the world and to identify the occurrence and likely role of microcystins in these events. After an initial screening of 134 publications, 42 publications (25 on the chronic and 17 on the acute effects of cyanotoxins) describing 33 cases of poisonings by cyanobacterial toxins in 11 countries were reviewed. The countries were Australia, China, Sri Lanka, Namibia, Serbia, Sweden, UK, Portugal, Brazil, USA, and Canada. At least 36 publications link cyanobacteria/cyanotoxins including microcystins to adverse human health effects. The studies were published between 1960 and 2016. Although the scattered epidemiological evidence does not provide a definitive conclusion, it can serve as additional information for the medical assessment of the role of microcystins in cancer development and other human health problems. This paper discusses the major cases of cyanotoxin poisonings as well as the strengths, weaknesses, and importance of the performed epidemiological research. This study also proposes some recommendations for future epidemiological work.

Toxic cyanobacteria and cyanotoxins in European waters – recent progress achieved through the CYANOCOST Action and challenges for further research

“…Recent reviews on human and animal health aspects include: a health review chapter (Codd et al, 2017), an epidemiological assessment of cancers in Serbia with reference to cyanobacterial blooms (Svirčev et al, 2014a), a review of production, toxinology and toxicology of the ANTX-a and STX neurotoxins (Testai et al, 2016) and a review on epidemiological investigations on health issues related to cyanotoxins (Svirčev et al, 2017a). Recently reported animal intoxications involving cyanobacterial blooms and cyanotoxins have included dogs in the Netherlands, with hANTX-a (Faassen et al, 2012b) and MC-LR (Lürling and Faassen, 2013) as likely proximal causes.…”

Effects of Chronic Exposure to Microcystin-LR on Kidney in Mice

“…Cyanobacterial blooms are an increasing problem worldwide and increasingly attract public attention, since microcystins (MCs) produced by them can cause a series of water quality problems and pose hazards to human and animal health [1][2][3][4][5][6][7]. MCs are a family of cyclic heptapeptide endotoxins.…”

A Global Analysis of the Relationship between Concentrations of Microcystins in Water and Fish

“…Large-scale blooms are considered unsightly and may cause foul odors (Watson et al, 2016), and many cyanobacteria may also produce toxic secondary metabolites (Wiegand and Pflugmacher, 2005). The negative effects of cyanobacterial toxins (cyanotoxins) have been observed for over a century (Francis, 1878) and, in terms of impacts to humans, include interruptions to municipal water supplies, closures of recreational sites, and illness (Griffiths and Saker, 2003;Bullerjahn et al, 2016;Svirčev et al, 2017).…”