Tetrodotoxin Posioning in Humans

As described on other pages, tetrodotoxin is a harmful toxin that blocks voltage-gated sodium channels, preventing nervous impulse. It is one of the most fatal neurotoxins and has no known antidote[8]. The cause of fatality is the loss of diaphragm contraction, resulting in respiratory failure. The LD50 in humans (for oral ingestion) is 334micrograms of TTX per kilogram. This means for a group of 91kg (200pound) adult males, a dose of only .03g of TTX would kill half of them. This is particularly scary, because some tissues may have about .0022gTTX/ (g of tissue), meaning a mean ten grams of this tissue would have a good chance of killing you.

Symptoms of TTX poisoning include headache, difficulty breathing, nausea, vomiting, blurring of vision, vertigo, and general prickling sensation. Treatment for TTX poisoning is symptom oriented, usually focused on respiration. Generally doctors try to keep the patient alive using whatever life support system is necessary until the TTX has worm off, which can take up to one day. If a patient survives a day, chances are that they will live[7]. Death can occur anywhere from twenty minutes to twenty hours of ingestion. Incidences rarely occur in the US, and mostly affect Japan, where a type of prepared puffer fish called “fugu” is considered a delicacy[1]. However, even in Japan, most cases of poisoning are due to fishermen eating their own catches. Cases of TTX poisoning have severely decreased in recent years, due to public awareness of the potentially life ending results.

Tetrodotoxin may have some benefits too. A study conduct by Marcil et. al. found that TTX may be a useful numbing agent[9]. It is not understood  well enough for this to be a practical application today, it would be far too risky.

 

 

 

 

 

 

 

Questions? Comments? Contact Me at minuttle@davidson.edu

Other Animal Physiology Topics

This website was created as a part of a class project in the Animal Physiology Class at Davidson College.