Hi Rosemary - Sorry to hear about your dogs. I have no idea how to prevent it, but would like to know what giardia is/does to animals/people? Penny in fridgid Nova Scotia - -20C and with the windchill its -40C - coldest yet this winter >>> Rosemary Carlson <rcarlson@mis.net> 01/13 8:27 PM >>> Hi everyone: As some of you know, I've just moved from the city into the woods. Love it here BUT, within a week or so, all 3 of my dogs were sick. After trying to treat them myself, I took them to their vet - and they were diagnosed with giardia. Apparently, contracting giardia is common with animals (and people!) in the woods - and is a special fear of hikers. They've all been treated and are now well - but, here's my question. How do I keep them from contracting the same thing all over again?? The fact that their backyard is forest floor isn't going to change! TIA! Rosemary in the foggy, rainy Eastern KY mountains http://www.morehead-st.edu/people/ro.carls