Transatlantic Impacts of Ciguatera Poisoning (CP) from Lutjanus bohar: a Traditional CP Paradigm Shift

The international seafood trade can transport geographically localized hazards to non-endemic regions, such as ciguatoxins (CTXs) which can cause ciguatera poisoning (CP) in humans. In 2020, two commercial packages of frozen “red snapper steaks”, product of India, were collected in Germany from a large lot of product imported into
the European Union (EU) in 2017, distributed to twelve countries, and responsible for an outbreak of CP. In 2017, three similar commercial packages of red snapper steaks from India, associated with one case of CP, were collected in the United States (US). Initial investigation of the US samples found CTX-like bioactivity, but the typical CTX
markers used for confirmation (C-CTX-1 and P-CTX-1/CTX-1B) were not detected, leaving the case un-confirmed. From the US samples, 9 of 11 portions from the three commercial packages were positive for CTX-like toxicity, as determined by mouse neuroblastoma cytotoxicity (N2a) assay, containing 0.50-6.26 ppb CTX-1B equivalents (Eq.). All EU samples (7/7 portions from two commercial packages) were positive, containing 0.79-5.39 ppb CTX-3C Eq. LC-MS/MS analysis detected CTX analogues exclusively from the CTX-3C class in all N2a positive samples. All products
(mislabeled in the US) were verified by DNA barcoding as Lutjanus bohar, a species associated with CP in the Indo-Pacific region. These findings break from several historical trends in US CP cases. First, CP outbreaks in the US are
typically geographically localized and caused by only one fish in a given lot. Second, the majority of past US cases have been associated with the presence of C-CTX-1 or CTX-1B marker compounds. The finding of multiple toxic fish within a lot of frozen pre-packaged steaks/filets with a transatlantic distribution, the exclusive finding of CTX-3C
analogs, and the association with L. bohar are all new occurrences in the US and will need to be monitored in the future.