text: In 1979, 138 inhabitants of Palm Island, Queensland, Australia, were admitted to hospital, suffering various symptoms of gastroenteritis. All of these were children; in addition, 10 adults were affected but not hospitalised. Initial symptoms, including abdominal pain and vomiting, resembled those of hepatitis; later symptoms included kidney failure and bloody diarrhoea. Urine analysis revealed high levels of proteins, ketones and sugar in many patients, along with blood and urobilinogen in lesser numbers. The urine analysis, along with faecal microscopy and poison screening, could not provide a statistical link to the symptoms.  All patients recovered within 4 to 26 days, and at the time there was no apparent cause for the outbreak. Initial thoughts on the cause included poor water quality and diet, however none were conclusive, and the illness was coined the “Palm Island Mystery Disease”.
  At the time, it was noticed that this outbreak coincided with a severe algal bloom in the local drinking water supply, and soon after the focus turned to the dam in question. An epidemiological study of this “mystery disease” later confirmed that the Solomon Dam was implicated, as those that became ill had used water from the dam. It became apparent that a recent treatment of the algal bloom with copper sulfate caused lysis of the algal cells, releasing a toxin into the water. 
  A study of the dam revealed that periodic blooms of algae were caused predominantly by three strains of cyanobacteria: two of the genus Anabaena, and Cylindrospermopsis raciborskii, previously unknown in Australian waters. A mouse bioassay of the three demonstrated that although the two Anabaena strains were non-toxic, C. raciborskii was highly toxic. Later isolation of the compound responsible led to the identification of the toxin cylindrospermopsin.
  A later report alternatively proposed that the excess copper in the water was the cause of the disease. The excessive dosing was following the use of least-cost contractors to control the algae, who were unqualified in the field.