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Eating dream fish, newts, frogs and shellfish

Category: Food

Type

Involuntary and voluntary

Introduction and description

 Over the years, a sort of myth has grown up about so called dream fish or hallucinatory frogs or similar strange tales.  Many of these little creatures do indeed cause hallucinations, delerium and indeed death, occasionally if ingested, but the reason for this is, I am afraid somewhat prosaic and none too pleasant.

 

 

Background

 

Tetrodotoxin is a potent neurotoxin with no known antidote.  Its name derives from Tetraodontiformes, the name of the order that includes several species which carry the toxin. Although tetrodotoxin was discovered in fish and found in several other animals, it is actually produced by certain symbiotic bacteria, such as Microbacterium arabinogalactanolyticum,  Serratia marcescens, and certain Vibrio, as well as the actinomycete Nocardiopsis dassonvillei,  plus some others that reside within these animals.  Tetrodotoxin has been isolated from widely differing animal species:

  • Arthropoda Xanthidae crabs
  • Chordata Amphibia Salamandridae – in other words newts
  • Chordata Amphibia Bufonidae – Atelopid frogs
  • Chordata Osteichthyes Tetraodontidae :
    • Blowfish
    • Globefish
    • Puffers
    • Rabbitfish
    • Swellfish
    • Toadfish
    • Sharp backed puffers
  • Chordata Osteichthyes Diodontidae
    • Burrfish
    • Porcupine fish
  • Chordata Osteichthyes Gobiidae
    • Yellowfin toxic goby
  • Mollusca Gastropoda Buccinidae, Bursidae, Terebridae etc – all marine snails
  • Cephalopoda Octopodidae – Blue ringed octopus
  • Balistidae
    • file fish
    • triggerfish
  • Molidae - ocean sunfish or mola
  • Ostraciidae - Boxfish
  • Echinodermata Asteroidea Astropectinidae – Starfish
  • The trumpet shell Charonia sauliae
  • The Ivory shell.
  • Nassarius spp Natica spp – gastropod mollusks

Another source also mentions the following:

  •  certain angelfish
  • a polyclad flatworm
  • several species of Chaetognatha (arrow worms)
  • several nemerteans (ribbonworms)

The organs (e.g. liver) of the pufferfish, for example,  can contain levels of tetrodotoxin sufficient to produce paralysis of the diaphragm and death due to respiratory failure.  Although not all puffer fish contain tetradotoxin, some contains saxitoxins which produces symptoms consistent with tetradotoxin.  Tetrodotoxin is slightly less neuroactive than saxitoxin, but its effects are more prolonged.  Saxitoxin produces less hypotension and vomiting than tetrodotoxin.

Salamanders such as the Californian newt and the eastern salamander contain sufficient quantities of tetrodotoxin to cause death following ingestion.  There has been at least one report of a fatal episode in Oregon when an individual swallowed a rough-skinned newt Taricha granulosa.  The rough-skinned newt (Taricha granulosa) is a North American newt known for its strong poison.  Many newts produce toxins to avoid predation, but the toxins of the genus Taricha are particularly potent. Toxicity is generally experienced only if the newt is ingested.

Tetrodotoxin is “roughly 100 times more poisonous than potassium cyanide”.   Toxicity varies between species and at different seasons and geographic localities. It is not always fatal; however, at near-lethal doses, it can leave a person in a state of near-death for several days, while the person continues to be conscious.   Tetrodotoxin does not cross the blood brain barrier, therefore consciousness typically remains intact during the peripheral blockade of neurologic function.  Symptoms typically develop within 30 minutes of ingestion, but may be delayed by up to four hours; however, death can be very quick.  A 65-year-old tourist in south Florida, for example, ate the liver of a puffer (Sphraeroides testudineus Linnaeus) common in the area (Benson, 1956). Symptoms appeared within 5 min. and the victim died 45 min. after eating the fish.

Many victims are unable to move; even sitting may be difficult. There is increasing respiratory distress. The victim, although completely paralyzed, may be conscious and in some cases completely lucid until shortly before death. Death usually occurs within 4 to 6 hours, with a known range of about 20 minutes to 8 hours.  If the patient survives 24 hours, then recovery without any residual effects will usually occur over several days.  There are no antidotes.

Other toxins

Seafood as a whole seems particularly susceptible to toxin accumulation.  The toxins vary and include:

  • Tetramine – that can affect shellfish, notably red whelks [Neptunea antiqua] as opposed to the more common edible whelk
  • Brevetoxin – that affect various shellfish
  • Saxitoxin – also affect various shellfish
  • Ciguatoxins  - both fish and shellfish. 

And so on. 

Any large carnivorous fish can accumulate toxins such as ciguatoxin via the food chain.  The algae attached to coral for example is a source, as are various sea plants.  The carnivorous fish eats the herbivorous fish that feed on the toxin containing detritus, algae or plants.  The fish themselves are unaffected by the toxins, they accumulate these toxins, the greatest concentration is to be found in the gut – which is why it is important to gut fish.

There are well over 400 species of fish for example that are ‘vectors’ for ciguatera poisoning – barracuda, grouper, red snapper, parrot fish, surgeon fish, moray eel, shark and amber jack.  Preparation by cooking ,salting etc does not destroy the toxins and  the fish remain toxic for long periods even after freezing.  And you cannot detect the poisons.  There is no taste taint.

The effects of all these toxins are much the same as we saw for tetrodotoxin, although their toxicity varies.  None appear to be quite as lethal as tetrodotoxin.  The person suffers from nausea, vomiting, hypotension, occasionally tingling in the mouth, occasional diarrhoea, memory loss, paralysis, respiratory distress and sometimes death.

The toxins are very often a result of toxic organisms such as bacteria, but quite a number of toxins come from algae.  Red algae for example [Chondria armata] was the cause of amnesic shellfish poisoning in eastern Prince Edward Island, Canada.  ‘Haffs' disease’ noted among fishermen along the Baltic Sea coast of East Prussia and at Lake Ysmen in Sweden has claimed more than a thousand victims who have consumed eels, eel livers, and a few other kinds of fish. Animals that ate the fish also became ill and died. Initially Selenium was thought to be the cause, but toxic blue-green or other algae in the food chain of the fish has also been suspected [Source: Fish Poisoning: A Problem in Food Toxication - ALFRED F. BARTSCH and EARL F. McFARREN].

As the planet heats up and we pour more of our own pollutants into the sea, I assume the algal blooms will increase and the toxicity of fish will increase correspondingly.

Dinoflagellates  are mostly marine plankton, but they are common in fresh water habitats as well. They are an important part of the aquatic food chain. But Karenia brevis is a source of neurotoxic shellfish poisoning producing brevotoxins.  Blooms occur annually in Florida coastal waters.  The Iliad describes red tides and ancient Greeks named the Red Sea for the occasional occurrence of reddish waters attributed to such phytoplankton blooms.  Many of the cases of hallucinations and delerium that occurred in the 17th century in Europe and North America in the 18th were consistent with paralytic shellfish poisoning.  Saxitoxin has been isolated from these red blooms.  Bivalve mollusks accumulate these neurotoxins during the filtering of water for food

Not only shellfish, but fish have, however, caused poisoning.  For example, at Rita and Uliga islands, in the 1950s, 35 families with a total membership of 375 persons were visited to obtain information on their experiences with fish poisoning during the previous year. During the questioning it became obvious that at least some persons differentiated common diarrheal disease from fish poisoning. Fourteen per cent of the persons questioned reported that they had been victims of fish poisoning; 6 per cent were hospitalized and the other 94 per cent reported to the OPD for treatment.

Rock cod (Epinephelus fuscoguttatus For  skal), red snapper (Lutjanus vaigiensis Quoy and Gaimard), mullet (Chelon vaigiensis Quoy and Gaimard), and rabbitfish (Siganus puellus Schlegel) were each involved in only three incidents although many families normally ate these fish. Similar data on Majuro Island gave an attack rate of 15 per cent for the previous year. Here the implicated fishes were rock cod (probably Anyperodon leucogrammicus Cuvier, and Valenciennes), scavenger (Lethrinus sp.), and parrotfish (Callyodon pulchellus Ruppel).

Information obtained from the native population showed that some of the fish described as toxic were normally accepted readily and used as food, which leads one to conclude the toxin derived from some marine organism it had eaten, the fish was not of itself toxic

How it works

Scientifically Tetrodotoxin blocks action potentials in nerves by binding to the voltage-gated, fast sodium channels in nerve cell membranes, essentially preventing any affected nerve cells from firing by blocking the channels used in the process.  If you get hallucinations it is because you are dying.   Neither Tetrodotoxin nor any of the other toxins are hallucinant or psychedelic.  You thus get any experiences via .....

Toxins

Poisoning

 

Related observations