• Question: What is the most poisonous thing on this planet ?

    Asked by anon-220353 on 12 Jun 2019.
    • Photo: Rebecca Moon

      Rebecca Moon answered on 12 Jun 2019:

      A quick google tells me it is the box jellyfish. I had some recollection it was some form of insect that was highly venomous but didn’t have long enough teeth to inject it into a human, but clearly I have learnt something new today!

    • Photo: Shobhana Nagraj

      Shobhana Nagraj answered on 12 Jun 2019: last edited 12 Jun 2019 10:46 pm

      I am not sure if this is the most poisonous – but I think the Box jellyfish is supposed to be pretty lethal in terms of it’s sting, and I think also the funnel web spider is pretty nasty! I think there are a lot of really deadly spiders and snakes in Australia – I remember when I lived in Australia, we were always warned to leave our shoes upside down when we took them off and check them for spiders before putting on our shoes, incase any had crawled into them. I also remember we had to tap the ground with a stick before taking each step on a walk, to alert any snakes around that we were walking – as snakes picked up the vibration on the ground of the stick! The alternative was to always walk third in a line if you were in the outback/bush, so the snakes would know people were walking ahead of you – although good advice, it’s not great for the two people ahead of you on the path! 🙂

    • Photo: Rachel Hardy

      Rachel Hardy answered on 12 Jun 2019:

      Botulinum toxin is one of the most poisonous substances on this planet. This poison is produced by a certain type of bacteria, which can grow in old canned foods. Luckily, boiling these foods is sufficient to kill these bacteria and stop botulinum from being released. If humans come into contact with this poison, it causes nerve cells to stop working. These nerve cells normally transfer impulses to muscles, which tells them to contract. Botulinum stops these nerve impulses from being transmitted to muscles, meaning that they cannot contract. The end result is death, caused by complete muscle paralysis- including the muscles that allow us to breathe. Poisons like this are known as ‘neurotoxins’. Luckily for us, botulinum is extremely rare.

    • Photo: Deepak Chandrasekharan

      Deepak Chandrasekharan answered on 13 Jun 2019:

      Poisonous means you have to eat it or touch it to be affected whilst venomous means the thing has to bite or sting you to affect you.

      The most powerful poison is botox (as measured by something called the LD50 which is the amount of the substance which if eaten would kill 50% of those who ate it) and is produced by a bacteria called clostridium botulinum. It was discovered as it caused severe food poisoning from bad sausages (botulus is the Latin word for sausage).

      It acts by blocking the chemical signal that nerves send a to muscles to cause them to contract – this is why sometimes it is used for injections to reduce wrinkles by making the muscles underneath the wrinkled skin relax and stop contracting.

    • Photo: Kaitlin Wade

      Kaitlin Wade answered on 13 Jun 2019:

      I’ve searched a bit and found this website that goes through the top ten most poisonous animals on the planet: https://sciencebasedlife.wordpress.com/2011/04/12/the-most-poisonousvenomous-animals-in-the-world/.

      Seems to be the box jellyfish, followed closely by the king cobra. There are lots of poisonous plants too like deadly nightshade, water hemlock and tobacco. But I don’t think that I’d like to get in contact with any of them….

    • Photo: David Wilson

      David Wilson answered on 13 Jun 2019:

      There’s a few answers already so i thought i’d write a bit more about 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 (explained by Deepak above) is tiny – at most 1 nanogram per kilogram can kill a human.

      It was first identified as a cause of food poisoning due to incorrectly prepared sausage (which is how it got it’s name, botulus is Latin for sausage) in late-18th century Germany.

      It seems crazy that after talking about how dangerous botulinum is that we actually have a clincal use for it in cosmetics. Targeted injections of tiny amounts of the toxin stop particular muscles from working, relaxing muscles that would otherwise cause wrinkly skin. But it has also been applied to a range of clinical conditions, such as paralysing muscles that, if untreated, would cause crossed eyes..

    • Photo: Matthew Bareford

      Matthew Bareford answered on 13 Jun 2019:

      There is some arguements among scientists as to whether substance wise it is Botulinum toxin or polonium…

      Ingesting just 7 trillionths of a gram of the element polonium is enough to kill an adult!

    • Photo: Nina Rzechorzek

      Nina Rzechorzek answered on 13 Jun 2019: last edited 13 Jun 2019 10:56 pm

      Agreed about botulinum, but I think this is a good opportunity to explain the difference between some confusing terms in the world of pharmacology (drugs) so here goes:

      Toxicity: refers to the adverse or lethal reaction to an administered dose of a medication, measured by the ‘lethal dose 50’ (LD50; the dose where 50% of test subjects are expected to die). A drug with a small LD50 is more toxic than one with a high LD50 because if the LD50 is small, we would need to give a smaller dose to kill the same proportion of test subjects when compared to a drug with a higher LD50. However, we cannot assume that a drug with a large LD50 is safe. This is because the LD50 considers only lethality and ignores any non-lethal adverse effects. An illness or serious negative side effect may occur with a much smaller dose, even in a drug with a high LD50.

      Efficacy: the maximum effect a drug can cause at any given dose. The ‘effective dose 50’ (ED50) is the dose at which the desired effect is produced in 50% of test subjects.

      Therapeutic index: a quantitative measurement of the relative safety of a drug that compares the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes toxicity. In non-human animals studies this is usually expressed as the LD50 divided by the ED50.

      Potency: refers to the relative dose that is necessary to produce a drug effect of a desired magnitude.

      And just a shout out for the various species of cone snail that produce deadly conotoxins in their venom fired via harpoon – potentially enough to kill a person. I love the fact that we have medical uses for some of the most deadly toxins on the planet – this includes botulinum toxin and some conotoxins.

      Pretty much anything can be toxic in the right dose but when it comes to the most dangerous living entity on the planet, I reckon humans win hands down.

    • Photo: Kate Timms

      Kate Timms answered on 17 Jun 2019:

      I was always told it was the box jellyfish. Jellyfish in general are pretty scary. I was snorkelling in Thailand once and got a tiny sting, freaked out, swam as fast as I could for the boat and refused to go back in the water! Some people had died recently nearby from jellyfish stings so I wasn’t taking any chances!

      Also blood poisoning from bacteria – known as sepsis – is very, very dangerous and is likely to get even more dangerous with antibiotic resistance.

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