Can fire ant bites kill you?
Dear Straight Dope:
A friend of mine says that she heard that the toxins from a fire ant bite stay in your system forever and if you're bitten and receive enough of these toxins that you would eventually die. Sounds a bit silly to me.
Your friend has mangled the facts a bit, but there's a grain of truth in there. Like virtually every other naturally-occurring venom (as opposed to a "toxin," which can be all sorts of things), ant venom breaks down and dissipates quickly. No insect venom stays in the body for more than a few hours--any delayed symptoms are secondary immune system reactions, and once they've started, the venom itself doesn't need to be there for the symptoms to persist. What does stay in the body are the antibodies produced by your immune system in response to the venom, and it's the antibodies that trigger the release of histamine and other chemicals that cause allergy symptoms. Under certain conditions, you can become allergic to a venom upon repeated exposure, so the idea that "as one gets stung more often, the odds of dying go up" isn't farfetched--but it has nothing to do with an accumulation of venom, and everything to do with how flaky your immune system is, and whether you're one of those folks whose body becomes more, rather than less, sensitive to allergens over multiple exposures. You have to be really sensitive to die from an allergic reaction to an insect sting, but it happens, most commonly with honeybee venom due to a condition known as anaphylaxis. The antibodies are generally specific to a given insect's venom, so if you're allergic to fire ant stings, you may very well not be allergic to honeybee stings, and vice versa (though if you're intrinsically allergy-prone, the odds of being allergic to both are higher).
Ultimately it comes down to the idiosyncrasies of each person's immune system. There's no guarantee that two people receiving identical venom exposures will display the same response. Your response to a venom can vary over time depending upon the condition of your immune system due to diet, overall health, or other factors. As a field biologist working with bees and wasps I get stung all the time by lots of different types of critters, but my immune system isn't hypersensitive, so I do fine, and have no fear that I'm accumulating toxins in my body--at least nothing other than the ones I'm breathing in, eating, or drinking in my air, food and water. Those are worth worrying about.