Giardia

Gardia lamblia, also known as gardia, giardia intestinalis or giardia duodenalis, is a microscopic parasite and causes the intestinal infection gardiasis.

ME/CFS
In 2004, in a region of Bergen, Norway, 1252 people were exposed to gardia lamblia through a contaminated water supply. A significant number of these subsequently developed chronic fatigue syndrome and/or irritable bowel syndrome. The Bergen outbreak of CFS has resulted in a number of long-term studies assessing the immunology of patients with chronic fatigue syndrome.