Thursday May 6, 2021, 12:30pm GMT+2
Ciguatera Fish Poisoning and Gambierdiscus species in Australia and the Pacific
1 University of Technology Sydney, School of Life Sciences, PO Box 123 Broadway NSW 2007, Australia
Ciguatera Fish Poisoning (CFP) is an illness caused by the accumulation of Ciguatera Toxins (CTX) produced by certain species of Gambierdiscus in edible fish. It is common in Australia and the wider Pacific region. In Australia, > 1400 cases and two fatalities were reported over a ~45 year period, with an estimated reporting rate of ~10%, indicating ~300 cases occur annually. Prior to 2014, only one CFP event was linked to a fish caught south of Queensland (29°S). Since then, 26 cases of CFP have occurred in more southerly regions, including a fish caught at Crowdy Head (32°S), the most southerly reported fish containing CTXs. The warming East Australian Current and its southward intrusion appears linked to the increased and more southerly distribution of CFP.
This expanding public health threat has highlighted the need to assess our knowledge of CFP, CTXs Gambierdiscus in Australia and the Pacific. Since 1991, when the first Gambierdiscus spp. from Australia were isolated and cultured, knowledge of the diversity and CTX production of Gambierdiscus has greatly expanded. Few Gambierdiscus species cultured worldwide produce P-CTX 4A, 4B, 3C, which are the analogs known to bioconvert to P-CTX-1B in the presence of fish liver enzymes. In Pacific countries neighbouring Australia, such as the Cook Islands and French Polynesia, the species G. polynesiensis consistently produces high levels of P-CTX 4A, 4B, 3C, and its abundance has been significantly positively correlated with CFP incidences in reef fish.
In Australia, four new Gambierdiscus species have been found (G. lapillus, G. honu, G. holmesi, G. lewisii) and these and other species found (G. carpenteri, Fukuyoa spp.) do not produce known CTXs. However, relatively few studies have been conducted. This work will build on our knowledge of CTX causative and vector species to provide the information needed to manage increasing risks of CFP in Australia.