Well, I guess I'm not very qualified to answer as I don't use GSE as a preventative measure. After reading your post, I searched for other posts and have decided that this would be a good idea (I also use flea drops on my dog BEFORE it gets fleas, same as I get all my jabs before I get tetanus, rabies etc etc!). So, after searching the web, reading my uni books and asking my vet I have come up with...well not much! All I found out that was kinda relevant is that farmers use GSE in animal feeds to PREVENT types of fungal and bacterial growth on the food and intestinally. It is also used to treat water in areas where water would be undrinkable. So I think I might go to one of those herbalist stores and ask them if they know anything else. Like you, I would rather prevent something occuring than have to deal with it once its there.
HTH a little
