Emerging tropical diseases in Australia. Part 2. Ciguatera fish poisoning

Abstract

Ciguatera poisoning is a food-borne neuro-intoxication caused by consumption of finfish that have accumulated ciguatoxins in their tissues. Ciguatera is a distressing and sometimes disabling condition that presents with a self-limiting though occasionally severe gastro-intestinal illness, progressing to a suite of aberrant sensory symptoms. Recovery can take from days to years; second and subsequent attacks may manifest in a more severe illness. Ciguatera remains largely a pan-tropical disease, although tourism and export fish markets facilitate increased presentation in temperate latitudes. While ciguatera poisoning in the South Pacific was recognised and eloquently described by seafarers in the 18th Century, it remains a public-health challenge in the 21st Century because there is neither a confirmatory diagnostic test nor a reliable, low-cost screening method to ascertain the safety of suspect fish prior to consumption. A specific antidote is not available, so treatment is largely supportive. The most promising pharmacotherapy of recent decades, intravenous mannitol, has experienced a relative decline in acceptance after a randomized, double-blind trial failed to confirm its efficacy. Some questions remain unanswered, however, and the use of mannitol for the treatment of acute ciguatera poisoning arguably deserves revisiting. The immunotoxicology of ciguatera is poorly understood, and some aspects of the epidemiology and symptomatology of ciguatera warrant further enquiry.

An Updated Review of Ciguatera Fish Poisoning: Clinical, Epidemiological, Environmental, and Public Health Management

“…The neurologic symptoms vary among patients and include paresthesias (i.e., numbness or tingling) in the hands and feet or oral region, metallic taste, sensation of loose teeth, generalized pruritus (itching), myalgia (muscle pain), arthralgia (joint pain), headache, and dizziness. A distinctive neurologic symptom is cold allodynia, sometimes referred to as “hot–cold reversal,” an alteration of temperature perception in which touching cold surfaces produces a burning sensation or a dysesthesia (i.e., unpleasant, abnormal sensation) [60]. One study revealed that intra-cutaneous injection of CTX in humans elicited this sensation [61].…”

Ciguatoxic Potential of Brown-Marbled Grouper in Relation to Fish Size and Geographical Origin

“…24,25 In Japan, an E. fuscoguttatus sample from ciguatera outbreak in Okinawa was confirmed to be toxic (0.1 MU/g fish flesh). 26 Another E. fuscoguttatus sample was found to contain mainly CTX-1B, with MBA result of 0.13 MU/g.…”

“…In Queensland, mainly P-CTX-2 and P-CTX-3 (each with 30% potency of P-CTX-1) 44 were found, together with a P-CTX-1 level of 0.3 μg/kg. 24,25 In Okinawa, mainly CTX-1B (P-CTX-1) was found, together with 52-epi-54-deoxyCTX-1B. 27 It is estimated that the lowest P-CTX-1 level associated with mild toxicity is 0.1 μg/kg fish flesh, and ingestion of ∼1.0 μg/kg of P-CTX-1 will produce clear toxic symptoms.…”

Voltage‐gated sodium channels: (NaV)igating the field to determine their contribution to visceral nociception

“…; Stewart et al . ). Intracolonic administration of purified P‐CTX‐1 also causes pain behaviour in mice (Inserra et al .…”