Giardia is a microscopic protozoan that lives in the intestinal tract of many animals worldwide. Unlike other common parasites, it is not considered a worm. Rather, it is a single-celled organism that can cause gastrointestinal upset (i.e. diarrhea and vomiting) in some animals.
Giardia is more common in areas that are densely populated with animals. This includes kennels, daycares, shelters, and large cities. Because of this, it is frequently diagnosed in animals that live in downtown Indianapolis.