Rosemary; I did a search and came up with 4097 results. I didn't read all of them obviously but here are a couple you might take a look at. It may be acquired by the dogs walking on bird (or other infected animals) feces then licking their paws or from water contaminated by animal or bird feces. It may also affect humans if their water is contaminated. http://www.flatcoat.com/giardia.htm http://www.cisti.nrc.ca/programs/indcan/uti/uti037.htm It is probably something those of us with pets should be aware of no matter where we live since it can be transmitted by bird feces comtaminating an outdoor water container or even by the pet walking on the feces then licking their paws. I have one who wouldn't stop at walking in it, she would have to roll in it. Martha M Brown NW Oklahoma, USA USDA Zone 6b, Sunset Zone 35