Ciguatera is a human
food poisoning caused by consumption of tropical and subtropical fish that have, through their diet, accumulated
ciguatoxins in their tissues. This study used laboratory mice to investigate the potential to apply blood collection cards to biomonitor
ciguatoxin exposure. Quantitation by the
neuroblastoma cytotoxicity assay of Caribbean
ciguatoxin (C-CTX-1) spiked into mice blood was made with good precision and recovery. The blood collected from mice exposed to a sublethal dose of Caribbean ciguatoxic extract (0.59 ng/g C-CTX-1 equivalents) was analyzed and found to contain detectable toxin levels at least 12 h post-exposure. Calculated concentration varied from 0.25 ng/ml at 30 min post-exposure to 0.12 ng/ml at 12 h. A dose response mice exposure revealed a linear dose-dependent increase of
ciguatoxin activity in mice blood, with more polar
ciguatoxin congeners contributing to 89% of the total toxicity. Finally, the toxin measurement in mice blood exposed to toxic extracts from the Indian Ocean or from the Pacific Ocean showed that the blood collection card method could be extended to each of the three known
ciguatoxin families (C-CTX, I-CTX and P-CTX). The low matrix effect of extracted dried-blood samples (used at 1:10 or 1:20 dilution) and the high sensitivity of the
neuroblastoma assay (limit of detection 0.006 ng/ml C-CTX-1), determined that the blood collection card method is suitable to monitor
ciguatoxin at sublethal doses in mice and opens the potential to be a useful procedure for fish screening, environmental risk assessment or clinical diagnosis of
ciguatera fish poisoning in humans or marine mammals.