The exotic world of deadly poison

The Amazon frog was a beautiful shade of luminous green and didn’t resist being picked up. The guide looked alarmed: “I think you should put it down and wash your hands.” It didn’t help. Within minutes, the palm of my hand was so painful I nearly vomited and actually checked the back to see if something had drilled right through. The excruciating pain lasted half an hour. The little guy sure packed a poisoned punch. 

It’s reckoned there are more than 300 species of poisonous frogs in the Amazon. They’re part of a class of creatures worldwide you want to avoid, including (at rough count) 1,200 kinds of poisonous sea organisms, 700 poisonous fish, 400 venomous snakes, 60 ticks, 75 scorpions, 200 spiders, 750 poisons in more than 1,000 plant species and several birds whose feathers are toxic when touched or eaten. 

As Homo sapiens radiated out of Africa to populate the world, they must have poisoned themselves in the thousands while working out what to eat in new lands and what not to mess with. It’s amazing we survived. Columbus solved the problem by taking dogs on his second voyage to taste foods his crew had to eat in exchanges of goodwill with natives of newfound cultures.

A venomous southern Pacific rattlesnake tastes the air in Santa Ynez Canyon in Topanga State Park on May 21, 2008 in Los Angeles, California. Image: David McNew / Getty Images

A venomous southern Pacific rattlesnake in Santa Ynez Canyon in Topanga State Park on May 21, 2008 in Los Angeles, California. Image: David McNew / Getty Images

American green tree frog. Image: Joel Henry / Unsplash

Golden poisonous frog. Image: Ruben Engel / Unsplash

Dart Poison Frogs appear at a sneak preview of "Frogs: A Chorus of Colors" at the American Museum of National History May 25, 2004 in New York City. Image: Chris Hondros / Getty Images

Webster’s Dictionary describes poison as a substance that, through its chemical action, usually kills, injures, or impairs an organism. It’s generally used for defence or attack — except by humans, who have employed it throughout history for murder. 

Deadly poisons active in small quantities have been a favourite way of offing opposition or unwanted spouses, especially since, until recently, there was no way to establish whether poison was involved.

It was liberally used to get rid of troublemakers and rulers in ancient Greece (Socrates was forced to take poison hemlock), Persia (Artaxerxes III and IV), China (a string of emperors), Rome and the rest of Europe (the Borgias made a science of it in Italy). After Hitler shot himself, his wife, Eva Braun, died by taking cyanide (after testing it on her dog), as did 18 leading Nazis. And millions died from Zyklon B in Nazi death camps – nearly 8,000 people were gassed each day at Auschwitz-Birkenau.

Russian President Vladimir Putin uses poison against his enemies (former spy Alexander Litvinenko died three weeks after being poisoned by radioactive Polonium-210) and the Russian leader fears it, using a food taster before meals. 

And let’s not forget Spider-Man, who exists by the grace of a radioactive spider bite, Snow White’s poison apple and the poison-dipped sword that Laertes used to kill Hamlet.

The most fabled poisoner was undoubtedly Giulia Tofana, a 17th-century entrepreneur, innovator, and (some might say) altruist who helped other women escape bad marriages and abusive husbands. She set up a cosmetics line which included a product labelled Aqua Tofana, marketed as makeup, which was laced with arsenic, lead and belladonna. Women, many trapped in arranged marriages, could slip it into their husband’s food or drink. At the time it was untraceable in the corpse. 

The potion was thought to have “removed” more than 600 men, making her one of the most successful serial killers in history. Known to history as the Queen of Poison, she sold the mixture for more than 50 years until she was caught, tortured and killed. Many of her clients were garrotted or strangled. Ever afterwards, for several centuries, arsenic was nicknamed “inheritance powder”.

Animals with no armour and often limited mobility have a different need for poison: defence. The creature with the deadliest venom is the Australian inland taipan. A single bite from the snake can contain enough venom to kill 100 people (or 250,000 mice, which it hunts). A definite case of overkill.

Taipan. Image: David Clode / Unsplash

Australian inland taipan. Image: Pixy

Amazonian poison arrow frogs are also killers. There are more than 300 species and a 5cm frog packs enough poison to kill up to 20 humans. So it’s fortunate my mishap was with a lesser variety.

There’s also stuff that’s simply inimical to cellular life, like radioactivity. First prize in that department, however, are the spores of a soil bacterium called C. botulinum. They’re the most poisonous known substance and very hard to kill. They can survive in boiling water, so the commercial food industry must use super-heated canning systems. The toxic micro-beasties are widely distributed in nature and can be present on all food surfaces.

C. botulinum stops nerve cells from firing and acts at such low volume that a litre milk bottle of the stuff could kill more than six billion people. It’s neutralised by keeping food at 100°C for 10 minutes. Remarkably, there are relatively few cases of poisoning from this bacterium, but it’s a good idea to always clean your chopping board.

We also create poisons to work for us and they go by many names: biocide, fungicide, germicide, herbicide, pesticide, insecticide and even spermicide. 

We also surround ourselves with plants, the poison content of which we are usually completely unaware. Citrus fruits are evidently toxic to dogs, cats and other animals, apple pips have a small amount of a cyanogenic glycoside, mango leaves contain the same substances as poison ivy, cassava contains hydrogen cyanide which is only neutralised by cooking, nutmeg has a mild neurotoxin that can cause euphoria and, in quantity, hallucinogenic visual distortions.

Several types of beans, cherry pips, rhubarb, tomato and potatoes (if they turn green) are, to some degree, mildly toxic and grapes, evidently, are toxic to dogs.

Out in the garden, there’s poison in Natal lily, jimson weed, poinsettia, snowdrops, flame and fire lily, Lantana camara, privet, daffodil, oleander, passion flower, elephant’s ear, frangipani, bracken, syringa, all euphorbias, arum lily, foxglove, clivia and many more.

Clivia. Image: Pixabay

Given the danger (and treachery) of the world, why don’t more of us die of poisoning? It’s because our bodies are designed to protect us from both natural and human-made toxins. 

The first line of defence is skin. It’s so waterproof, tough and tightly woven that only the smallest and most fat-soluble molecules can get through. Our sense of smell also warns us of noxious substances; if they fail there’s vomiting as a backup. 

Finally, your liver turns fat-soluble poisons into water-soluble wastes that can be flushed out through your kidneys. The balance tilts over to toxicity only when we step over the threshold of dosage.

As for the frog that turned my hand to fire, like many creatures that have no need to hide, it was absolutely beautiful. So are monarch butterflies, but they’re deadly. Many birds, simply on seeing them, instinctively throw up. DM/ML

---

Visit Daily Maverick's home page for more news, analysis and investigations

---