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THE PACIFIC CIGUATERA NETWORK
A bright blue cephalophis Argus swims through a reef

ABOUT CIGUATERA

WHAT IS CIGUATERA?

Ciguatera poisoning can occur when consuming contaminated seafood. It affects people after they have eaten certain seafood, usually, fish, that contain the poison ciguatoxin.

The poison is produced by microscopic algae called epiphytic dinoflagellates. This algae is found in shallow coastal waters, living on the surface of seaweed and other marine plants, such as corals. This algae is most commonly found in warm, calm waters with high salinity.

Herbivorous fish that eat these seaweeds and nibble on corals, then also consume the toxic epiphytic dinoflagellates.  Toxins then begin to build up in the fish as they are consuming the poison, and their bodies cannot break it down.

These fish are then consumed by carnivorous fish, such as tuna, and the toxins move up the food chain, becoming more concentrated as the larger fish consume the smaller fish.

Toxins are then transferred to human consumers, who might have caught these fish themselves, and can cause serious illness and in extreme cases, death.

A graphic of ciguatoxins being transferred from algae, to small fish, to big fish, to people's dinner plates
WHAT TO DO IF YOU SUSPECT YOU HAVE CIGUATERA POISONING

If you suspect that you may have consumed ciguatoxins and may be suffering from ciguatera poisoning, please seek help from your doctor or nearest healthcare provider. Request that the attending doctor informs local public health authorities if ciguatera poisoning is diagnosed, in order for the case to be recorded.

SIGNS AND SYMPTOMS

Signs and symptoms of ciguatera poisoning include a range of neurological and gastrointestinal issues that can occur within 1-24 hours of consuming the contaminated seafood. The severity of the symptoms is dependant on the concentration of the toxin in the fish in conjunction with the individual susceptibility of the consumer. The symptoms can last from weeks to months, however in extreme cases may become chronic.

The symptoms of ciguatera poisoning can include:

  • Numbness, tingling, or a burning sensation around the mouth, hands or feet
  • Joint or muscle pains with weakness or cramps
  • Vomiting, diarrhea, chills, itching, headache, sweating, and dizziness
  • Reversal of temperature sensation in the mouth
  • Unusual taste sensations
  • Difficulty breathing
  • Extreme itchiness
  • Nightmares and hallucinations
PREVALNECE

Knowledge of the global burden of the disease is fairly limited. Ciguatera poisoning is known to be underreported in official state systems as doctors are often unaware of the obligation to report cases, in addition to the illness being frequently misdiagnosed.

According to the World Health Organization, it is estimated that up to 10 percent of the local population in the Pacific Islands are affected by ciguatera poisoning annually.

TYPES OF CIGUATOXINS

Three distinct categories of ciguatoxins have been established based on their geographical origins: Indian, Caribbean, and Pacific ciguatoxins. Each of these categories shares a fundamental chemical structure, but subtle variations in this structure contribute to notable differences in toxicity. Up to now, researchers have identified 47 CTXs, though less than half of them have undergone structural characterization due to a lack of sufficient purified toxin standards for analysis. In the Pacific Islands region, only Pacific ciguatoxins, specifically P-CTX-1 (the most potent), P-CTX-2, and P-CTX-3, have been detected in fish flesh. The “P” indicates the toxin’s origin (Pacific), “CTX” represents ciguatoxin, and the number signifies the analogue (chemical variant).

HOW CAN YOU REDUCE THE RISK OF CIGUATERA POISONING?

Distinguishing fish contaminated with ciguatoxins from non-ciguateric fish is challenging, and there is currently no reliable rapid test method available. However, you can minimize the risk of ciguatera by following these precautions:

  • Refrain from catching or consuming fish from areas known to have ciguatera, speaking with local fishers or experts may be the best way to find this information.
  • Avoid consuming the head, roe, liver, or other viscera, as these tissues tend to contain higher concentrations of ciguatoxins compared to the flesh, potentially increasing exposure.
  • When consuming warm water ocean fish, limit portions to no more than 7 ounces.
  • If ciguatera-like symptoms arise, refrain from further consumption of that fish and promptly seek medical advice. It may be helpful to store a portion of the fish in the freezer for later laboratory analysis (~1 ounce) if symptoms develop.
  • Be mindful that improper cleaning and storage of fish can lead to general food poisoning (not ciguatera).
HOW IS IT TREATED?

Currently, there is no universally proven treatment for ciguatera poisoning. The approach to treating ciguatera poisoning centers on relieving the symptoms experienced by individuals affected. Following the onset of ciguatera, specific foods may trigger relapses or intensify existing symptoms. It is generally recommended to abstain from consuming seafood, nuts, alcohol, and caffeine. Seek guidance from your healthcare provider for effective symptom management.

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CONTACT

Eileen Nalley
Ocean and Coastal Ecosystem Health Specialist
University of Hawai’i
Sea Grant College Program
Honolulu, HI 96822
enalley@hawaii.edu
Phone: (808) 956-7031