Immunity to Poison

When I was a kid, I was allergic to many things. My physician gave me a series of desensitization shots. From what I was told, they contained small amounts of the substances that I was allergic to. Is this similar to eating poison ivy, as mentioned in Cecil’s column? Why do some people become more sensitive to a substance after repeated exposure?

“Mithridatization”, huh? I wasn’t familar with the expression, but it immediately made me think of Housman’s Terence, this is stupid stuff.

I tell the tale that I heard told.
Mithridates, he died old.

Dashiell Hammett used Mithridatization (I never heard that word before, either) as the central plot twist in his short story Flypaper. The poison was arsenic (apparently an ingredient in old-fashioned flypaper), and the poisoned individual was a woman trying to build up resistance so she could bump off her hoodlum boyfriend by putting arsenic in the pot from which they both ate. It didn’t work – she got sick and died instead. At the end, the Continental Op consults with the Old Man, his boss at the Continental Detective Agency and a person familiar with every known crime. The Old Man had, of course, heard of the arsenic trick. He described a little of its history, then mentioned that it, well, just doesn’t work for everybody. Something for the Dread Pirate Roberts to keep in mind.

Since mithridatization (catchy word) is so dangerous, what happens to the horses that aren’t “self selected,” because we’ve decided they’re going to make antivenin or antitoxin? Do half of them die, are horses tougher than people, or what?

It’s a different deal. Desensitization is to make your immune system say, “Oh, yeah – I know that one – no big deal,” and stop giving false positives. Poisons generally don’t involve your immune system.

Because someone is otherwise sure to ask, I’ll add that vaccination is also different. Vaccination works by giving your immune system just one sample of a virus or bacterium, so it can train itself to attack it. Desensitization works by exposing the body over and over again, over a period of years, to the same allergen, until the immune system gets bored.

What about the ‘common knowledge’ notion that you can gain an immunity to beestings after repeated stings over time?

I don’t work with venomous snakes, but I have a friend who collects, keeps and milks them so I’ve picked up a bit of second hand knowledge.

There are three main types of snake venom:

Neurotoxin - Affects the nerves and brain, and therefore muscles and breathing. The king cobra is a good example of pure neurotoxic venom. Either it

Cytotoxic – I prefer the term digestive venom since it breaks down the cells. This is usually used in combination with other toxins since the digestive enzymes also help get the venom to the blood system. The rattlesnake is a good example of this. Rattlesnakes actually use the venom as part of their digestion so when feeding it will inject a lot more venom than when it is just trying to make you go away. A rattlesnake with its venom glands removed will need to eat more since without the digestive enzymes in its venom it doesn’t get as much nutrition from its food.

Hemotoxin – Affects the blood. I don’t like this classification since it is based more on what cells the venom affects than how it actually works. A venom that stops the heart is probably a neurotoxin, and one that breaks down red blood cells is probably a digestive venom. However, some hemotoxins will also cause, or prevent blood clotting.
Even a small amount of a digestive venom will cause harm to your body, so trying to build an immunity to rattlesnake venom will really cause local scaring in the muscles and blood vessels. It will help protect you from some of the neurotoxic or hemotoxic affects, so it will help you survive a bite but the damage you will do to your body it’s quite a price to pay to protect yourself in the unlikely event that you get bitten (even if you keep rattlesnakes as pets and therefore have a much greater chance of getting bitten, I still don’t think it’s a good idea).

Neurotoxins tend to either kill you or not, so it is possible to inject small, but gradually increasing, amounts of them to build up a stronger immune response. Unfortunately this resistance fades over time (it’s gone in roughly a year), so unless you have a ready supply of snake venom to keep giving yourself monthly doses this isn’t practical. Then again, unless you have a snake handy there isn’t much need to be immune to the effects of the venom.

It also appears that it isn’t possible to develop a resistance to some venoms. For example, there is one venom that causes a massive drop in blood pressure which this doesn’t kill you, it just makes it impossible to do anything but lie on the ground for a few hours. This venom appears to be almost identical to the chemicals that the body uses to regulate blood pressure, so anyone who was immune to effects would probably die from high blood pressure.

Since my friend had a king cobra he decided to actually try and develop an immunity to the venom. He started by milking the cobra, diluting the venom and then figuring out the smallest amount it would take to kill a mouse (on hand to feed the snakes). This was the initial amount he injected. Every week he would slightly increase the dose until it was up to a dose that would probably kill a person. He never planned to work up to the dose from a full king cobra, since that would require a lot of milking and he didn’t see a need since if he could take large dose with no adverse affects, then he would likely survive a full bite. He had to get rid of the cobra so he never finished this project.
A few other notes:

For treating a neurotoxic snake bite on an arm, wrap the arm with a few tensor bandages from the shoulder to the wrist and keep the arm still. You aren’t trying to stop blood circulation, you’re just trying to stop the venom from spreading through the lymph system. Then relax, think about next steps. This will give you several hours before the venom affects your brain, lungs or heart. With a digestive enzime this won’t help - get medical attention quickly.

In the US, the standard snake anti-venom is made for a range of rattle snakes. This means that it will do nothing for you if you’ve been bitten by a cobra. Unfortunately most hospitals don’t know this, and don’t have other anti-venoms available, so they will give it to you anyway. So if you are bitten by a cobra, start calling the reptile zoos in the area to find a suitable anti-venom.

If you are given the standard US anti-venom and survive you will now have an allergy to horses (and it you get given the anti-venom again you’ll almost definitely go into anaphylactic shock). This is because the venom is produced using horse antibodies and the manufacturing process leaves a lot of other horse proteins in the anti-venom. There are better manufacturing processes that don’t leave horse proteins behind but no one has had the money to go through the drug approval process.

In the name of not wasting, I sometimes like to eat food which has been in the fridge for slightly too long. The idea being that I can build up tolerance in my gut to the various factors that cause food to get old while in the fridge. I’m not sure what those factors may be (mold, bacteria), and I don’t know if I can train my gut to be more robust. I am not too adventurous in that I avoid foods with any new odors or visible mold.

Any suggestions?

Along these lines, why do some people get sick when traveling to other places and eating their food or drinking teir water, whereas the locals seem relatively fine? I’m thinking it has something to do with the types of organisms we have in our gut…

Better than eating poison ivy leaves, drink milk from goats that eat it. Saves the probability of having mouth or other internal sores from the stuff. I understand that it doesn’t taste that good, but I have heard from several goat owners that it does serve the purpose of causing an immunity to poison ivy. And goats are already immune to the stuff and find it to be a taste treat.

hi there,

Visha Kanya

in ancient India (and prevalent even hundred years ago), a girl was fed poison from a very young age and as an adult, would be used as a live poison vial. See’s_Daughter for some details. Many ancient Indian stories and mythology have references to the Visha Kanya.

Although, I have not met one, the fact that it is in many stories (written and folklore), I would think that there is some truth to it. There might be some ayurvedic and/or puranic literature that would have details on the poisons that were consumed by the girls/women.


This came up recently in another thread. I noted that Adrienne Mayor’s book addressed this, although at shorter length than I had recalled.
The bottom line – there’s no evidence that you could so produce a “poisonous” maiden. But it’s awfully tempting to think that the idea originated from an infected maidemn carrying disease into the camp.

Hello cydwatts, and welcome to the SDMB.

I think that although there is some anecdotal evidence for the case of goat’s or cow’s milk giving immunity, there are a couple of reports which cast some doubt on this. I looked into this a while ago after my face swelled up due to poison ivy in my back yard. Here are some notes that I collected:

Dairy goats used to clear poison oak do not transfer toxicant to milk. Kouakou, B., D. Rampersad, E. Rodriguez, and D.L. Brown, 1992 California Agriculture 46(3): pp. 4-6.

The lead researcher, Kouakou, also wrote about it in his Master’s thesis:

Fate of urushiol (poison oak toxicant) when consumed by dairy goats. Kouakou, B., 1991 Thesis, Univ. of Calif., Davis:

Now, that doesn’t disprove a beneficial link, but it does indicate that the chance of there being a positive link may be reduced.

Can’t vouch for the authenticity of this video but I’ve seen something like it on TV…churches where they drink poison, pass around snakes etc.