Ciguatera

What is ciguatera?

Ciguatera is a food-borne illness caused by eating reef fish contaminated with a toxin called "ciguatoxin". Ciguatoxin is tasteless and odourless. Fish contaminated with ciguatoxin cannot be identified by appearance. Ciguatoxin is not destroyed by cooking, smoking, freezing, canning, salting or drying.

What is my risk?

Travellers who consume large reef fish, such as barracuda or moray eel, are at risk.

Ciguatera occurs in very localized outbreaks, so it is very difficult to predict risk. One fish on one day may be safe to eat and the same species of fish on another day may not be safe to eat.

The risk of ciguatera is higher after events that disturb coral reefs, like tsunamis.

The risk is higher among those who:

• sport fish and eat their catch
• eat fish that weigh more than 3 kg
• eat the heads, viscera (organs and intestines) and roe (eggs) of reef fish

How is it transmitted?

Ciguatera toxins are produced by small sea algae that live around coral reefs in tropical and sub-tropical oceans. The algae are eaten by smaller fish which are then eaten by bigger fish. The toxins become more concentrated as they move up the food chain and they remain harmless to the fish but act as a poison in humans.

What are the symptoms?

Symptoms can occur within minutes, but generally develop within 24 hours of eating contaminated fish.

Most people recover completely within a few days or weeks, but in very rare cases, ciguatera can be fatal.

Initial gastrointestinal symptoms include nausea, vomiting, diarrhea and abdominal pain. These symptoms may last several days.

Neurological symptoms develop after the initial symptoms, and include:

• tingling and numbness around the mouth, lips, throat, arms and legs
• sore muscles and tooth pain
• temperature reversal (hot things feel cold and cold things feel hot)
• feeling tired, headaches and itchy skin

In rare, severe cases of ciguatera, neurological symptoms can last months or longer.

Can ciguatera be treated?

There is no cure for ciguatera, but it usually resolves on its own.

There are treatments that may provide relief from some symptoms of ciguatera.

Where is ciguatera a concern?

Ciguatera occurs in tropical and sub-tropical areas of the:

• Caribbean Sea
• Indian Ocean
• Pacific Ocean
• New areas continue to be identified, including the Canary Islands, the eastern Mediterranean and the western Gulf of Mexico.

Ciguatera can also occur after eating fish imported from tropical or sub-tropical areas.

Recommendations

Consult a health care provider or visit a travel health clinic preferably six weeks before you travel.

1. Avoid eating reef fish.
   • Some examples of reef fish include barracuda, moray eel, amberjack, snapper, grouper, sea bass and sturgeon fish.
   • If you cannot avoid eating reef fish:
     • Avoid eating large reef fish (fish that weigh more than 3 kg), although keep in mind that small fish may also cause ciguatera.
     • Avoid eating the heads, viscera (organs and intestines) and roe (eggs) of reef fish.
   • Remember, ciguatoxin is tasteless and odourless. Fish contaminated with ciguatoxin cannot be identified by appearance.
   • Ciguatoxin is not destroyed by cooking, smoking, freezing, canning, salting or drying.
2. If you are sport fishing, find out if there have been any cases of ciguatera associated with fish caught in the area you are fishing in. Avoid eating any fish that is considered dangerous by the local population.