One of the biggest challenges at the moment is that there is no standard test for the poison, partly because it causes poisoning in extremely low concentrations. In addition, different chemical structures of ciguatoxins are known, which can vary by location.
But after an outbreak at the end of 2012, the German Federal Institute for Risk Assessment (BfR) sent samples of leftovers eaten by those affected, and samples of fish batches, to the European Reference Laboratory for Marine Biotoxins in Spain.
The facility was able to positively identify ciguatoxin using a method it established last year. According to a study, the latest German outbreak was caused by red snapper fillets, which a German importer had obtained from an Indian distributor. The affected shipment was recalled as soon as it was confirmed as the source of illness.
German authorities reported a total of 14 cases of such poisoning.
Metabolites produced from algae
Ciguatoxin is generated by metabolites produced from algae, belonging to the species dinoflagellates, which originate from coral reefs of subtropical and tropical marine areas of the Caribbean, and the Indian and Pacific Oceans.
Once consumed by fish they accumulate and enter the food chain. "Ciguatoxin poisoning is one of the most common types of fish poisoning worldwide", said professor Andreas Hensel, president of German Federal Institute for Risk Assessment (BfR).
"However, this type of poisoning was confined to certain regions of the world until recently. As a result of the worldwide trade with tropical and subtropical fish, an increase in incidence of such poisoning is to be expected."
Initial symptoms include nausea, vomiting and diarrhoea. Most people also later suffer from extremely unpleasant sensations such as burning, tingling and pain on contact with cold. Feelings of numbness in the hands and feet, weakness and muscle pain and hot and cold flushes can also occur. These symptoms can persist for months.