Evidence for the Range Expansion of Ciguatera in French Polynesia: A Revisit of the 2009 Mass-Poisoning Outbreak in Rapa Island (Australes Archipelago)

• Main Authors: Mireille Chinain, Clémence Mahana iti Gatti, André Ung, Philippe Cruchet, Taina Revel, Jérôme Viallon, Manoëlla Sibat, Patrick Varney, Victoire Laurent, Philipp Hess, Hélène Taiana Darius
• Format: Article
• Language: English
• Published: MDPI AG 2020-12-01
• Series: Toxins
• Subjects: ciguatera poisoning; French Polynesia; <i>Gambierdiscus</i>; ciguatoxins; epidemiology; toxicological analyses
• Online Access: https://www.mdpi.com/2072-6651/12/12/759

Ciguatera poisoning (CP) results from the consumption of seafood contaminated with ciguatoxins (CTXs). This disease is highly prevalent in French Polynesia with several well-identified hotspots. Rapa Island, the southernmost inhabited island in the country, was reportedly free of CP until 2007. This study describes the integrated approach used to investigate the etiology of a fatal mass-poisoning outbreak that occurred in Rapa in 2009. Symptoms reported in patients were evocative of ciguatera. Several <i>Gambierdiscus</i> field samples collected from benthic assemblages tested positive by the receptor binding assay (RBA). Additionally, the toxicity screening of ≈250 fish by RBA indicated ≈78% of fish could contain CTXs. The presence of CTXs in fish was confirmed by liquid chromatography tandem mass spectrometry (LC-MS/MS). The potential link between climate change and this range expansion of ciguatera to a subtropical locale of French Polynesia was also examined based on the analysis of temperature time-series data. Results are indicative of a global warming trend in Rapa area. A five-fold reduction in incidence rates was observed between 2009 and 2012, which was due in part to self-regulating behavior among individuals (avoidance of particular fish species and areas). Such observations underscore the prominent role played by community outreach in ciguatera risk management.