Question - The article cited below states “In February 1996, an outbreak of illness occurred at a hemodialysis clinic in Caruaru, Pernambuco State, Brazil. At this clinic 116 (89%) of 131 patients experienced visual disturbances, nausea, vomiting, and muscle weakness, following routine hemodialysis treatment. Subsequently, 100 patients developed acute liver failure. As of December 1996, 52 of the deaths could be attributed to a common syndrome now called ‘Caruaru Syndrome’.” What was the etiology of this outbreak?
Answer- The cited article notes “Examination of previous years’ phytoplankton counts showed that cyanobacteria were dominant in the water supply reservoir since 1990. Analyses of carbon and other resins from the clinic’s water treatment system plus serum and liver tissue of patients led to the identification of two groups of hepatotoxic cyanotoxins: microcystins (cyclic heptapeptides) in all of these samples and cylindrospermopsin (alkaloid hepatotoxic) in the carbon and resins.” (Azevedo S. et al. Human intoxication by microcystins during renal dialysis treatment in Caruaru-Brazil. 2002 Toxicology 181-182:441-446)