Since the Palm Island outbreak, several other species of cyanobacteria have been identified as producing CYN: Anabaena bergii, Anabaena lapponica , Aphanizomenon ovalisporum, Umezakia natans, Raphidiopsis curvata. and Aphanizomenon issatschenkoi. In Australia, three main toxic cyanobacteria exist: Anabaena circinalis, Microcystis species and C. raciborskii. Of these the latter, which produces CYN, has attracted considerable attention, not only due to the Palm Island outbreak, but also as the species is spreading to more temperate areas. Previously, the algae was classed as only tropical, however it has recently been discovered in temperate regions of Australia, Europe, North and South America, and also New Zealand.
In August 1997, three cows and ten calves died from cylindrospermopsin poisoning on a farm in northwest Queensland. A nearby dam containing an algal bloom was tested, and C. raciborskii was identified. Analysis by HPLC/mass spectrometry revealed the presence of CYN in a sample of the biomass. An autopsy of one of the calves reported a swollen liver and gall bladder, along with haemorrhages of the heart and small intestine. Histological examination of the hepatic tissue was consistent with that reported in CYN-affected mice. This was the first report of C. raciborskii causing mortality in animals in Australia.
The effect of a bloom of C. raciborskii on an aquaculture pond in Townsville, Australia was assessed in 1997. The pond contained Redclaw crayfish, along with a population of Lake Eacham Rainbowfish to control the excess food. Analysis revealed that the water contained both extracellular and intracellular CYN, and that the crayfish had accumulated this primarily in the liver but also in the muscle tissue. Examination of the gut contents revealed cyanobacterial cells, indicating that the crayfish had ingested intracellular toxin. An experiment using an extract of the bloom showed that it was also possible to uptake extracellular toxin directly into the tissues. Such bioaccumulation, particularly in the aquaculture industry, was of concern, especially when humans were the end users of the product.
The impact of cyanobacterial blooms has been assessed in economic terms. In December 1991, the world's largest algal bloom occurred in Australia, where 1000 km of the Darling-Barwon River was affected. One million people-days of drinking water were lost, and the direct costs incurred totalled more than A$1.3 million. Moreover, 2000 site-days of recreation were also lost, and the economic cost was estimated at A$10 million, after taking into account indirectly affected industries such as tourism, accommodation and transport.