Giardia

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

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.

Notable studies
2004 Bergen outbreak
 * 2012, Immunophenotyping in post-giardiasis functional gastrointestinal disease and chronic fatigue syndrome - (Full text)
 * 2013, Chronic fatigue syndrome 5 years after giardiasis: differential diagnoses, characteristics and natural course - (Full text)
 * 2017, Giardia-specific cellular immune responses in post-giardiasis chronic fatigue syndrome - (Full text)
 * 2017, From good health to illness with post-infectious fatigue syndrome: a qualitative study of adults’ experiences of the illness trajectory - (Full text)
 * 2018, Prevalence of Irritable Bowel Syndrome and Chronic Fatigue 10 Years After Giardia Infection - (Full text)