Giardia is another single celled organism that is found in dog’s and cat’s intestines. This organism is found in water and can infect a pet when they drink from a water source that has been contaminated by an infected animal’s feces. Often times in light infection loads there are no symptoms, however, in heavier infections diarrhea, vomiting and/or weight loss maybe seen. The best way to help keep your pet safe from this organism is by providing clean drinking water. Diagnosis is confirmed by looking at a fecal sample under the microscope and identifying giardia or by a testing for the giardia antigen. However, this organism is not always easily seen with the microscope and sometimes the test not be unreliable. Many times, if the doctor suspects your pet may have giardia, they will simply treat for this organism and see if issues resolve.