When it comes to deadly poisons many people often think of cyanide, arsenic or strychnine as some of the most dangerous ones out there. However, a recent article points out that although these poisons are well known, there are several others that have been deemed the most deadly.
The LD50 (lethal dose, 50%) is the amount needed to kill 50% of the test population and is how toxicity is most often assessed. The article explains that it is usually quoted per kilogram (kg) of body weight. On this scale, for example, sodium cyanide comes out at around six milligrams per kg. On the other hand, the LD50 of tetrodoxotin (the pufferfish toxin that poisons around 50 Japanese people every year), is around 300 micrograms per kg if orally ingested, and as little as 10 micrograms per kg if injected.
Assessing toxicity is not easy. The chemical state of a substance is important, as is how we ingest it. Nevertheless, the article provides a representative selection, in ascending order, of five truly deadly poisons, all at least a hundred times more toxic than cyanide, arsenic or strychnine.
- Ricin: Obtained from the beans of the castor oil plant (Ricinus communis), which is cultivated to extract the oil – the ricin remains in the solid fiber. It interferes with protein synthesis in cells, causing cell death. It has an LD50 of 1-20 milligrams per kg if orally ingested, but far less can cause death if it is inhaled or injected.
- VX: The only synthetic compound in this list, VX is a nerve agent with the consistency of engine oil. It emerged from research into new insecticides in the early 1950s, but proved too toxic to use in agriculture. VX kills by interfering with the transmission of nerve messages between cells so muscle contractions became out of your control and can lead to death by asphyxiation.
- Batrachotoxin: From the skins of tiny frogs, batrachotoxin is collected by native Indians in western Colombia and put onto the end of blow-darts. The LD50 is around two micrograms per kg, meaning that an amount the size of two grains of table salt will kill you. It works by interfering with the sodium ion channels in the cells of muscles and nerves, jamming them open so that they do not close. This ultimately leads to heart failure.
- Maitotoxin: There are a number of potent marine toxins associated with harmful algal blooms in the sea and Maitotoxin is the most lethal of these substances. Formed by a dinoflagellate, a kind of marine plankton, it has a very complicated structure that increases the flow of calcium ions through the cardiac muscle membrane, causing heart failure.
- Botulinum toxin: Scientists differ about the relative toxicities of substances, but they seem to agree that botulinum toxin, produced by anaerobic bacteria, is the most toxic substance known. Its LD50 is tiny – at most one nanogram per kilogram can kill a human. It was first identified as a cause of food poisoning due to incorrectly prepared sausage in late 18 century Germany.
There are several botulinum toxins, with type A being the most potent. Clostridium botulinum type B is another type that can infect animals, especially horses, and accounts for more than 85% of equine botulism cases. Several studies place the mortality rate around 70% and scientists agree that prevention is the best defense.
Neogen offers BotVax® B, a USDA approved monovalent vaccine (toxoid) for the prevention of equine botulism Type B due to Clostridium botulinum in healthy horses. For more information, click here.
For more information on the world’s deadliest poisons, click here.