It is the battle between the animal kingdom and the plant kingdom in deciding which includes the most potent toxin? I know it is an unfair competition and it will only look at snakes and mushrooms, but still. Of course it will also vary depending on where you are in the world. Australia has among the most dangerous snakes but also the most dangerous mushroom. In Sweden on the other hand the snakes are almost harmless while some mushrooms can kill you. And in Iceland there are no snakes at all but some poisonous mushrooms. So let’s pick Australia to make the battle more even.
In the first corner we have the mushrooms
In early January 2012, the press in Australia was full of reports that three people had died after eating death cap mushrooms. Two of the victims got poisoned at a New Year’s Eve dinner party in Canberra at the Harmonie German Club. The chef and kitchen hand died after eating wild mushrooms the chef had cooked in a stir-fry meal for two further friends. He had mistaken the fungi for an edible variety of mushroom used in Chinese cooking. One of the friends also became critically ill while the other had only minor symptoms. Almost at the same time in Canberra, but in an unrelated incident, a further man died from preparing his own mushroom dish including death caps.
The incidents triggered a review of 12 previous cases of suspected death cap poisoning reported in Canberra and New South Wales between 1999 and 2012. Eight of the 12 patients sustained serious liver damage and four died, according to the study published in The Medical Journal of Australia. The death cap poison is particularly toxic to the liver.
Death cap mushrooms (Amanita phalloides) are considered to be the most poisonous mushroom in the world and less than one is enough to kill an adult human. The death cap is native to Europe, where it is widespread, but is believed to have been accidentally introduced into Australia through imported oak trees. Death caps can now be seen growing under oaks in Canberra and Melbourne. They are similar in appearance to several species of edible mushrooms commonly used in cooking, such as paddy straw mushrooms and caesar’s mushroom. They are said to have a pleasant taste by surviving consumers. The entire mushroom is poisonous and cooking or peeling the mushroom does not remove toxicity.
The symptoms of death cap poisoning are slow to develop and often do not appear until 10-16 hours after consumption. The first symptoms are stomach pains, vomiting and diarrhoea. These may continue for a day or two, after which there is typically an easing of symptoms and apparent recovery. This may last for 2 or 3 days after which the terminal phase starts with the re-occurrence of stomach pains, vomiting and diarrhoea – accompanied by jaundice. Without effective, early medical intervention, coma and death occur between one and two weeks after eating the mushroom. Death is caused by liver failure, often accompanied by kidney failure.
Death caps contain several types of toxin of which the amatoxins are the most dangerous. The lethal dose for humans is estimated at about 0.1 mg/kg body weight, so about 8 mg for an 80 kg person. It influences protein synthesis causing cell metabolism to grind to a halt killing the cell. If enough cells in a human liver or kidney are effected and die, then there will be catastrophic liver or kidney failure – and then death.
In the second corner the venomous snake
Let’s state upfront that eating a venomous snake is completely safe unless you have lacerations in your gastrointestinal system. But a snake bite can certainly be deadly.
In October 2012, a 26-year-old Toowoomba man was moving a wood pile and was bitten twice by an eastern brown snake. Emergency services went to the scene but the emergency helicopter was delayed by needing to refuel. It took two hours to get him to hospital for treatment with antivenene. He died five days later when he was taken off life support in a Brisbane hospital.
The estimated incidence of snakebites annually in Australia is between 600-3600 with an average mortality of 3-6 people per year with the availability of antivenene and early treatment. The eastern brown snake (Pseudonaja textilis) is considered to be the second most venomous terrestrial snake in the world and would account for about 60% of the deaths caused by snake bites in Australia (the most venomous is the inland taipan but it rarely bites humans).
The eastern brown snake is found throughout the eastern half of mainland Australia. It is aggressive and known for its bad temper. The fact that brown snakes are very fast-moving also adds degree to the danger they present. Not only is their venom ranked as the second most toxic of any land snake in the world, they thrive in populated areas, particularly on farms in rural areas with mice. Clinically, the venom of the eastern brown snake is known to cause diarrhea, dizziness, collapse or convulsions, renal failure, paralysis and cardiac arrest. Victims may collapse within a few minutes.
Among the toxins contained in their venom is a very potent presynaptic neurotoxin, one of the strongest of toxins found in snakes. The venom also contains a postsynaptic neurotoxin and a procoagulant. The presynaptic neurotoxin called textilotoxin act on the prejunctional nerve terminal by selectively blocking the release of acetylcholine after the appearance of the action potential and thus causing gradual paralysis. The postsynaptic neurotoxin called pseudonajatoxin A causes an irreversible blockade of muscle activity by firm binding to the acetylcholine receptors. The coagulation factor is a complete prothrombin activator.
The lethal dose for humans is estimated at 0.053 mg/kg body weight with a normal bite providing around 4 mg of venom. or more than enough to kill an 80 kg person.
And the winner is?
It is a bit of a dead heat. The brown snake venom is certainly the more potent (although established on mice) at about double the strength. More people also die from brown snake bites per year in Australia than from consuming death caps. On the other hand snake bites can be treated with antivenene while there is no good treatment for death cap poisoning. Consuming more than one death cap mushroom, as would be common, also considerably increases the risk of death.
My advice can only be to stay away from both eastern brown snakes and death cap mushrooms if at all possible.
- Venomous Snakes Of The Adelaide Hills Region (bartrumx.wordpress.com)
- Venomous Snakes (reptile101.wordpress.com)
- Eastern brown snake (Wikipedia)
- 5 deadliest mushrooms on earth (Environmental Graffiti)
- Deadly mushroom chemistry (Chemistry World)
- Mushroom poisoning (Wikipedia)