Ciguatoxin is the commonest form of fish poisoning in the tropics. It is produced by a dinoflagellate, Gambierdiscus toxicus, loosely attached to algae on coral reefs.
This species was first described by Adachi, R. & Fukuyo, Y in 1979 using samples collected around Gambier Islands.
Human ciguatera fish poisoning in the Gulf may be underreported or not diagnosed yet. The toxin is no doubt present in the Gulf. Dinoflagellates are implicated in causing the “red tide” phenomenon in the Gulf, also known as an algal bloom. The photosynthetic pigment in the algae gives it the red coloration.
Symptoms usually last a few days but can linger for months or years. There is no way to cure ciguatera, but a doctor may be able to treat the symptoms. After recovering, avoid a relapse by avoiding fish, nuts, alcohol, and caffeine for at least 6 months.
brevis. Fish species through the food chain are impacted, up to and including large predatory species such as sharks, as well as species typical in human consumption.
Paralytic shellfish poisoning is caused from the ingestion of toxin-contaminated bivalve shellfish and crustaceans. Algal blooms of dinoflagellates, usually during the warmer months of June to October, result in toxin accumulation in filter feeders such as bivalves.
CAUSATIVE AGENT: Neurotoxic Shellfish Poisoning (NSP) is caused by the consumption of molluscan shellfish (e.g. clams, oysters, coquinas, mussels and other filter feeders) contaminated with brevetoxins, which are produced by a marine dinoflagellate called Karenia brevis.
Gambierdiscus is a genus of marine dinoflagellates that produce ciguatoxins, a type of toxin that causes the foodborne illness known as ciguatera. They are usually epiphytic on macroalgae growing on coral reefs.
Maitotoxins increase the calcium ion influx through excitable membranes, causing cell depolarization, hormone and neurotransmitter secretion, and breakdown of phosphoinositides (important in regulating the function of integral cell membrane proteins).
The source of the toxin responsible for ciguatera fish poisoning is found in high levels in a marine organism (dinoflagellate Gamabierdiscus toxicus) that typically inhabits low-lying tropical shore areas and coral reefs.
Dinoflagellates are single-cell organisms that can be found in streams, rivers, and freshwater ponds. 90% of all dinoflagellates are found living in the ocean. They are better referred to as algae and there are nearly 2000 known living species.
- Avoid or limit consumption of reef fish.
- Never eat high-risk fish such as barracuda or moray eel.
- Avoid eating the parts of the fish that concentrate ciguatera toxin: liver, intestines, roe, and head.
Ciguatera is an important form of human poisoning caused by the consumption of seafood. The disease is characterised by gastrointestinal, neurological and cardiovascular disturbances. In cases of severe toxicity, paralysis, coma and death may occur. There is no immunity, and the toxins are cumulative.
Other fish known to sicken people include grouper, amberjack, hogfish, and to a lesser extent, snapper, mackerel and mahi mahi. “We definitely caution against eating barracuda,” Radke said.
Scombrotoxin, also called scombroid poisoning or histamine poisoning, happens after eating fish that contain high levels of histamine due to improper food handling. It remains one of the most common forms of fish poisoning in the U.S. and worldwide.
How can I protect myself from Diarrhetic Shellfish Poisoning? Check the Shellfish Safety Map for beach closures and advisories on the day you plan to harvest shellfish. We regularly test shellfish for biotoxins and close areas when unsafe levels are detected. Beaches are sometimes posted with warning signs.
Open ocean pelagic fishes such as tuna and mahi-mahi have not been associated with ciguatera poisoning. A wide range of symptoms has been reported, including generalized symptoms of profound weakness, chills, sweating, arthralgia, myalgia, and a metallic taste in the mouth.
brevis toxin may confirm red tide intoxication, in addition to the presence of increased dinoflagellate counts in water samples. Treatment focuses on prevention of drowning. Generally, affected manatees are propped up on foam to keep their heads above water for 24 to 48 hours and closely observed.
brevis, produce neurotoxins that can cause respiratory problems in humans and attack the central nervous systems of fish and other wildlife. Many scientists refer to blooms of K. brevis as harmful algal blooms (HABs) due to the impacts they can have on the environment, humans, and our coastal economies.
In marine (saltwater) environments along Florida’s west coast and elsewhere in the Gulf of Mexico, the species that causes red tides is Karenia brevis, often abbreviated as K. brevis. … brevis blooms from red tides caused by other species of algae, researchers in Florida call it “Florida red tide.”
There is no specific cure available for shellfish poisoning, and antibiotics do not shorten the illness. Drugs used to control diarrhea, vomiting, and stomach cramps should not be used except for bismuth (Pepto-Bismol). These drugs are referred to as antimotility drugs since they decrease stomach and intestine motion.
There is no antidote for Paralytic Shellfish Poison. The only treatment for severe cases is the use of life support systems such as a mechanical respirator and oxygen until the toxin passes from the victim’s system. Survivors can have a full recovery.
In patients with mild to moderate poisoning, effects resolve over 2-3 days, but in severe cases, weakness may persist for up to a week. In most fatalities, death occurs rapidly, typically within 12 hours.
Although not fatal to humans, neurotoxic shellfish poisoning is known to kill fish, invertebrates, seabirds, and marine mammals (e.g., manatees). It is caused by the brevetoxin family of toxins (brevetoxin + 10 related compounds9 produced by the dinoflagellate Karenia brevis (= Gymnodinium breve).
Gastrointestinal symptoms include abdominal pain, vomiting, and diarrhea. Neurologic signs and symptoms include paresthesias, reversal of hot and cold temperature sensation, vertigo, and ataxia. Inhalational exposure may cause respiratory symptoms such as cough, dyspnea and bronchospasm (1-4).
The term neurotoxicity refers to damage to the brain or peripheral nervous system caused by exposure to natural or man-made toxic substances. These toxins can alter the activity of the nervous system in ways that can disrupt or kill nerves.
Maitotoxin (MTx) is one of the potent polyether toxins produced by the dinoflagellate Gambierdiscus toxicus and, besides ciguatoxin, is the most common toxin involved in ciguatera fish poisoning (CFP). CFP-causing agents bioaccumulate in the aquatic food chain and may finally be ingested by humans and other animals.
Maitotoxin (or MTX) is an extremely potent toxin produced by Gambierdiscus toxicus, a dinoflagellate species. Maitotoxin is so potent that it has been demonstrated that an intraperitoneal injection of 130 ng/kg was lethal in mice.
Botulinum toxins, if prepared as an aerosol, have the potential to be potent biological weapons. One gram of an aerosolized botulism toxin is enough to kill about a million people, and a human toxic dose is on the order of a billionth of a gram.
Ciguatera poisoning is a form of food poisoning. It is caused by eating warm water finfish that carry ciguatera poison (toxin). Small plant-eating fish eat toxic algae and in turn are eaten by larger, predatory fish, like Spanish Mackerel.
There have been reports of ciguatera poisoning from human consumption of yellowtail snappers although such instances are considered rare for this species. Ciguatera poisoning is caused by dinoflagellates (microalgae) found on dead corals or macroalgae.
Treatment of ciguatera poisoning is primarily supportive. Intravenous hydration with crystalloid and electrolyte replacement may be necessary for dehydration. Severe or refractory hypotension may require a vasopressor. Antiemetics such as ondansetron may be beneficial.
Red tide is a marine environmental event where protists, including algae and dinoflagellates, go through a tremendous growth period, called a bloom, or an algal bloom. In a 2- to 3-week period, it is possible for each algal cell to produce 1 million daughter cells.
Bioluminescent dinoflagellates range in size from about 30 µm to 1 mm, and are found in all the world’s oceans. Occasionally they are found in high concentrations, resulting in red tides, so called because the high abundance of organisms discolors the water.
Dinoflagellates may be planktonic, or may live within another organism. Ninety percent of all dinoflagellates are marine plankton. There are also many freshwater species, some of which have been found growing in snow! They may be photosynthetic or non-photosynthetic; about half the species fall into each category.