From: Diana
Dear Jessica, I have a question about deworming horses. A friend of mine has stopped using any chemical (toxic) deworming products and says that she will never go back to "poisoning" her horses. She is trying to get me and my neighbors to use what she uses and give up the chemical products. She is giving her horses a natural product called Dietomaceous Earth that is 100% natural and acts to kill internal parasites in horses and also to kill flies somehow. She says that science has shown that this works. I am interested in this product because I like natural remedies, but I am not ready to give up my usual deworming pastes yet. My horses are very good about swallowing the paste and are in very good health. Is this natural substance really the ideal dewormer? My veterinarian just frowned when I asked him and said "People are incredible" and "Tell your friend to be careful" but that doesn't tell me what I want to know. I haven't found information about it anywhere so of course I am asking you! Can you help? Thanks! Diana
This brings us to your question about DE (Diatomaceous Earth). I think you'll find some information if you look it up under this spelling. DIAtoms are the
The phrase "science has shown" is more complicated than it seems. There have been some experiments with results that DID indicate that SOME parasites can be killed by diatomaceous earth (DE)... under the specific experimental conditions. The conditions did NOT involve horses. It's POSSIBLE that DE, if fed to horses, could kill internal parasites and possibly help control flies. But to my knowledge, there have been no experiments to indicate whether this would be truly effective AND SAFE if administered to horses. Then there's the question of dosage - how much would you give to a horse, and how often? There are no data to help here, and I would NOT recommend that you engage in what I call a "one-rat experiment" with your horse (or even a "ten-rat experiment" if you have ten horses).
As you probably know, "natural" is not the same as "safe". Tell your friend that we simply don't know enough about the effects of DE on equine internal parasites, and that she should not try to use this as a substitute for a proper deworming program. Tell her, also, that if she is going to be handling this substance frequently, she should wear a mask so as to avoid breathing it in. Another name for diatomaceous earth (DE) is crystalline silica, and high-level exposure to the dust from the product has been implicated in some forms of lung cancer. DE is very fine powder, and the dust from it is finer still - even a very slight air movement is enough to create a cloud that a handler or horses would be likely to inhale. The action that is supposed to kill parasites in the horse's stomach and intestines - a scrubbing action created by the razor-sharp edges of the particles - can cause bleeding and cysts in the lungs. In theory, a healthy horse's digestive system will be protected by intestinal mucosa, but not all horses are perfectly healthy - many have ulcers, and although, again, there's no hard evidence for this, I would suspect that horses with stomach or intestinal damage (ulcers, for instance) could be at risk for the same sort of abrasion that affects the lungs.
Oh, and speaking of lungs, how are yours - and how are your friend's lungs? If she is asthmatic, she shouldn't even be handling this stuff.
My personal "take" on matters like these is simple: I don't like to test potentially dangerous products on my horses - by the time I use any medication, I want to KNOW that it is effective and safe, and I want to know exactly how to store it, handle it, and dispose of the container. In the case of horses and medications, the word "natural" is appealing, but not necessarily indicative of purity or effectiveness, let alone safety.
Until there are some reliable studies to indicate genuine effectiveness AND to suggest suitable dosages - together with some helpful advice about storage, handling, and administration - I would suggest that you leave the diatomaceous earth alone and continue to follow the deworming program that your vet recommends for your horses.
Jessica
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