The first documented case of neurotoxicity in two patients following octopus flesh ingestion in the Mediterranean: a case study from the Maltese Islands (central Mediterranean)

Roberta Mifsud, Caroline Gouder, Alan Deidun, Mario J. Cachia, Stephen Montefort

Department of Medicine, Mater Dei Hospital, Msida MALTA
Department of Geosciences, Faculty of Science, University of Malta, Msida MSD 2080 MALTA


Tetrodotoxin is a naturally occurring potent neurotoxin, widely distributed in marine animals, including a number of members of the Tetraodontidae fish family (e.g. Lagocephalus sceleratus, the silver-cheeked toadfish), a marine invasive species native of the Indo-Pacific region which is increasingly being reported from the Mediterranean. Various human fatalities have been documented globally as a result of intoxication through tetrodotoxin, but these have rarely been associated with the ingestion of octopus flesh. We hereby report the case of two patients from the Maltese Islands (central Mediterranean) who presented symptoms consistent with neurotoxicity, following the consumption of the well-cooked flesh of the common octopus. Both patients required supportive care, until complete recovery within a few days, with one of whom requiring intensive care. The reported cases of neuromuscular disturbances following the consumption of octopus flesh is highly suggestive of neurotoxicity due to tetrodotoxin poisoning, the first such cases documented for the Mediterranean waters, although alternative scenarios are also postulated in this study due to the lack of definite evidence for the TTX poisoning, including the release of histamine by psychrotrophic bacteria or the accumulation of HAB-related toxins. The postulated TTX intoxication mechanism involves predation by Octopus vulgaris, the common octopus or ‘scuttle’, on a toxic marine species harbouring tetrodotoxin.

Keywords: Neurotoxicity, tetrodotoxin, octopus, Mediterranean

pdf-dl icon


Bane, V., Lehane, M., Dikshit, M., O’Riordan, A., Furey, A. (2014) Tetrodotoxin: Chemistry, toxicity, source, distribution and detection. Toxins (Basel) 6(2): 693-755.

Cavazzoni, E., Lister, B., Sargent, P., Schibler, A. (2008) Blue-ringed octopus (Hapalochlaena sp.) envenomation of a 4-year-old boy: a case report. Clin Toxicol (Phila) 46(8): 760-1.

Chand, P. (2009) Marine Envenomations. In: Clinical Neurotoxicology. Syndromes, Substances, Environments (ed., Dobbs, M.R.) Elsevier, Philadelphia, pp. 454-462.

Deidun, A., Fenech-Farrugia, A., Castriota, L., Falautano, M., Azzurro, E., Andaloro, F. (2015) First record of the silver-cheeked toadfish Lagocephalus sceleratus (Gmelin, 1789) from Malta. BioInvasions Records 4(2): 139-142.

Fell, S.D. (2017) Blue-Ringed Octopus Bite. Available at: ringed_octopus_bite/article_em.htm#blue-ringed_octopus_bite_facts (accessed 15 May 2018).

Gullian Klanian, M., Delgadillo Díaz, M., Sánchez Solís, M. (2018) Molecular characterization of histamine-producing psychrotrophic bacteria isolated from red Octopus (Octopus maya) in refrigerated storage. High-throughput 7(3): 25.

Gupta, P.K. (2016) Chemical food poisoning. In: Fundamentals of Toxicology Essential Concepts and Applications, (ed., Gupta P.K.), Elsevier, San Diego, pp. 327-331.

Haddad, J.V., Moura, R. (2007) Acute neuromuscular manifestations in a patient associated with ingesting octopus. Rev Inst Med Trop S Paolo 49(1): 59-61.

Karachle, P.K., Angelidis, A., Aposlopoulos, G., Ayas, D., Ballesteros, M.B.V. (2016) New Mediterranean biodiversity records (March 2016). Mediterranean Marine Science 17(1): 230-252.

Lopes, V.M., Lopes, A.R., Costa, P., Rosa, R. (2013) Cephalopods as vectors of harmful algal bloom toxins in marine food webs. Marine Drugs 11(9): 3381-3409.

Moustafa, A.Y., Awaad, A. (2016) Comparative histopathological and histochemical impacts induced by the posterior salivary gland and ink sac extracts of Octopus vulgaris in mice. The Journal of Basic & Applied Zoology 74: 23-36.

Noguchi, T., Arakawa, O., Takatani, T. (2006) TTX accumulation in pufferfish. Comparative Biochemistry and Physiology Part D: Genomics and Proteomics 1(1): 145-52.

Wu, Y.J., Lin, C.L., Chen, C.H., Hsieh, C.H., Jen, H.C., Jian, S.J., Hwang, D.F. (2014) Toxin and species identification of toxic octopus implicated into food poisoning in Taiwan. Toxicon 91: 96-102.