Answer by Rory Young:
None! Technically snake venom is not a poison, it is a venom. Poisons can be absorbed through the skin or digestive tract whilst venoms have to be injected into the tissue or bloodstream. This is why snake can be drunk which actually happens in parts Asia as it is believed to carry many health benefits.
In terms of toxicity there is as yet no definitive answer as the testing systems vary so greatly. There have also been no tests done of all using at least one of these systems. Most importantly though the different venoms may have characteristics that may make them deadly to the mice they are usually tested on and humans; in other words, unbelievably, they may be more toxic to mice than humans.
That being said, it is pretty much accepted that the most toxic venom is that of the. In studies done in Costa Rica the was found to be more than twice as venomous as any land snake. However, it is rare to receive a fatal bite because almost always only tiny amounts of venom are injected.
In terms of percentage of bites resulting in fatalies, the bites of both theand are almost 100% fatal. Others probably are too. I knew a herpetologist who was at that time the only person who had survived a full black mamba bite.
I did a course on snake bites with him many years ago in Zimbabwe. He explained that he had been working with a medical professional on a theory. Black Mambas are neurotoxic and kill by paralysing all the muscles in your body. Your first stop breathing and the last muscle to become paralysed is your heart. Their theory was that if you could keep the person’s lungs and heart going artificially until antivenom could work then someone could survive.
Amazingly he was bitten by a mamba, rushed to hospital by his wife and the very doctor he worked with met him their (within ten minutes of the bite) and they put him on a heart lung machine and pumped him full of anti-venom and antihystamine. He lived and had no lasting side-effects.
Sadly he was bitten again by a black mamba a few years later and this time died before he could get help.
In terms of fatalities India has the most fatalities reported of all countries and I believe theand are responsible. I have also read about the poor ladies in Sri Lanka who peak tea without protection to their legs and are frequently bitten and die.