Do you believe in the LD50 scale?

[ThomasH.]

The LD50 scale tests if a snake venom is medically significant by seeing if over 50 of a hundred mice are killed by it. We already know that some animals like dogs are pretty much immune to Aghkistrodon venom. What tells us that mice have the same defenses/weaknesses to certain venoms as primates?

[RioBravoReptiles]

I think the LD50 is important.. but not as important as many other factors in the envenomation of a human.
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Interesting topic.

[ThomasH.]

Is your avatar a real animal species?

[Xeikeness]

Actually, mice are genetically quite similar to humans, far more similar than dogs are. Personally, I feel that any animal-testing for toxins ought to be performed on pigs, who are so similar to humans that we can harvest and use their organs/blood.

Honestly though, yes I trust the tests because of the genetic similarities between mice and humans. They have thus far proven reliable, there is no reason not to trust them just because dogs happen to have an immunity to some toxins. Dogs are not genetically similar to humans(or mice).

[ThomasH.]

Still doesn't quite make sense, a human would probably still weigh more than all the mice. Ahh... I don't get it.

[Xeikeness]

Weight doesn't have much to do with it. The mice are dosed appropriately for their weight ratio in comparison to humans.

They take the "possible lethal dose" for humans, then decrease it to the same dosage by weight for the mice.

[RioBravoReptiles]

Originally Posted by ThomasH.

Still doesn't quite make sense, a human would probably still weigh more than all the mice. Ahh... I don't get it.

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The LD50 quantifies the relative toxicity of venoms.. How much reconstituted, freeze-dried venom calculated as a percentage of weight, does it take to kill 1/2 of the mice it is injected in. It's a valid scale of venom toxicity.
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It doesn't consider many real-life conditions of envenomation of humans by a snake.. Just as one example.. though a couple of sea-snakes do have extremely toxic venom on the LD50 scale.. what are the chances of a person being bitten?.. another example.. when a snake bites, venom is not automatically introduced into the wound.. that is a conscious, not autonomic function.. so the amount (if any) of venom given varies.. even if (and they do not) every snake had the capacity to deliver the same dose... many other factors apply.. way too many for anybody except laboratory cell-biologists and other people unconnected with real-life encounters with venemous animals.. to get really pumped-up over LD50 tests.
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That's what I thnk, anyway.

[SiUK]

I believe that its useful for finding out how much venom it takes to kill a test group of mice but as for on humans I think it is flawed.

[SteveJor]

Snakes in the wild should be rated taking into account, the proximity to humans, the agressiveness, venom yeild, venom toxicity, AV availability, and proximity of medical care to get a true measure of how lethal one type can be over another. LD50 is a good tool but I think you also need to look at other factors if measuring how a dangerous a bite from a wild snake would be.
However, the LD50 is a great gauge when working with these animals as captives.
For example, a snake with a low LD50 may be FAR more dangerous to people if the other criteria is taken into account versus a snake with a high LD50 that is found in remote areas far away from human populations.