Dientamoeba fragilis (PCR)

A single-celled organism in the large intestine whose significance as a cause of bowel complaints is disputed in studies. Transmitted faecal-orally, possibly also via pinworm eggs.

How Dientamoeba fragilis lives in the gut

Despite its name, Dientamoeba fragilis is not an amoeba but a flagellate that is related to the trichomonads and lost its flagella over the course of evolution. It lives inside the large intestine, particularly in the caecum and the ascending colon, and feeds there on bacteria and food residues. For a long time no resistant dormant form was known; only more recent investigations have described cysts, and rarely. How it is transmitted has therefore not been conclusively settled. It is frequently found in children and in their households.

Is Dientamoeba fragilis a pathogen?

Whether Dientamoeba fragilis causes complaints is disputed in studies. It does not normally penetrate the gut lining. Individual case reports describe inflammation of the colonic lining with eosinophil granulocytes, and some studies found Dientamoeba more often in children with abdominal pain and diarrhoea. Other studies found it just as often, or more often, in people without complaints. Since the more sensitive PCR has come into use, the organism has been detected much more often – which has reopened the question of its significance, but not answered it.

What happens when Dientamoeba multiplies heavily?

Large amounts of Dientamoeba have been described in studies and case reports together with abdominal pain, diarrhoea, bloating and tiredness, sometimes alongside a raised number of eosinophil granulocytes in the blood. Whether the organism is the cause or simply multiplies particularly well in an already altered gut environment has not been settled. Conversely, no disadvantage is known when Dientamoeba is absent: in individual microbiome studies, carriers even had a more diverse bacterial flora, and it was found less often in chronic inflammatory bowel disease – observed, but not explained.

The interpretation is given in your report.