Unlike most foodborne illnesses, Giardia (also known as beaver fever) is caused by a parasite, not a bacterium or virus. Its symptoms, which typically manifest themselves within two weeks of contracting the parasite, primarily involve gastrointestinal distress, such as abdominal cramping, diarrhea and greasy stools, gas, bloating, and nausea. These typically last for 1-3 weeks and often cause loss of weight and dehydration. However, there are individuals that do not exhibit systems of the infection.
Because Giardia thrives in the intestines of people and animals, infection follows the fecal to oral route. The parasite or its cysts may be found on contaminated objects aand consequently infection occurs when an individual consumes contaminated food or drink or touches objects that are contaminated. Swallowing improperly treated water is a common means of contracting the illness. It is diagnosed by means of a stool sample and can be treated with anti-parasite drugs, though the body can destroy the infection without the aid of medication.