Dientamoeba fragilis (DF) is an intestinal protozoan originally seen in the early 1900’s. For some decades it was thought to be a harmless commensal, despite numerous published reports of illnesses associated with the infection Although its role as a pathogenic agent remains controversial, DF has been linked to chronic diarrhea, abdominal pain, nausea, anorexia and excessive flatulence. DF has also been implicated as a cause of colitis in adults. Allergic colitis with peripheral eosinophilia secondary to DF infection has also been described.
Colonization may occur without development of disease. In adults, asymptomatic colonization is present in 75-85% of individuals affected by the parasite. In children, the opposite is true; disease develops in as many as 90% of those colonized. No specific mortality is associated with this enteropathogen. Morbidity related to acute infection is in the first 1-2 weeks of the disease, with symptomatology predominated by diarrhea. Chronic infection occurs after 1-2 months of illness and is manifested by abdominal pain.
Much has been learned about the epidemiology of DF since its original description. By 1924, only 33 DF cases were recorded world-wide. Over the past four decades its global incidence has been studied varying considerably, generally being higher in immune compromised patients. The use of adequate culture techniques has increased detection of DF significantly with reported rates as high as 18% in Israel, 36% in Holland and 42% in Germany. Higher rates of infection are seen in crowded conditions with poor personal hygiene.
Sampling and detection methods have an immense influence on the ability of a laboratory to detect DF. Identification is more probable when the fecal samples are examined in three rather than one sample and is not possible without the use of a fixative agent such as SAF (sodium acetate / acetic acid / formalin). There is also debate about whether the detection rate is higher in soft or fluid stool. When stool slides are suitably stained there is a five fold increase in the rate of detection. Therefore, methods used in the detection of DF are of crucial importance.
Transmission of DF still remains unclear although there has been fair substantiation of the hypothesis that pinworms (E. vermicularis) are the vector responsible for person to person spread. DF forms have been documented in the lumen of pinworms found in the human appendix. Many authors have now reported a higher than anticipated co-incidence of DF and E. vermicularis infections. In fact, Ockert experimentally infected himself with pinworm eggs from a child and subsequently developed DF infection. Now that’s dedication! Two other successful attempts at infecting humans with DF from pinworms were also described by Ockert. By contrast infection with DF by ingesting DF trophozoites has failed.
Symptoms
Though the ability of DF to cause disease is still questioned by some, the circumstantial evidence incriminating this organism as a pathogen is overwhelming. Onset of infection is accompanied by onset of colicky pain, loss of appetite, soft stools covered with mucus and irritation of the rectum. Numerous observations have shown that treatment which eliminates the organism results in clinical improvement. In the literature, abdominal pain, persistent diarrhea, pruritus, abnormal stool with mucus, flatulence, fatigue or weakness, occasional eosinophilia, alternating diarrhea and constipation, nausea or vomiting, weight loss, constipation, belching and tenesmus are found in decreasing order of frequency as symptoms in patients in whom only DF was identified. Many of these symptoms mirror the symptoms of IBS.
Diagnosis
Clinical suspicion of DF in patients with diarrhea predominant IBS needs to be confirmed by the demonstration of the parasite in stools. A laboratory which offers comprehensive stool testing should be used.
Trophozoites of DF degenerate rapidly and prompt fixation is necessary. In a laboratory aware of this organism, Giardia lamblia may be an uncommon pathogen by comparison, seen around 1/10 as commonly as DF. Hence, at least in clinical gastroenterological practice, DF is probably the most common detected parasite in some countries. Culture techniques are said to be the most sensitive method of detecting DF. However, few laboratories are capable of culturing DF at this stage.
Overall therefore, DF is infrequently sought for and is rarely detected using fresh, unfixed stool specimens.
Metronidazole (Flagyl), Tetracycline (Sumycin) and Iodoquinol (Vytone, Yodoxin) are all conventional drugs used in the treatment of DF.
Signs, symptoms & indicators of Parasite, Dientamoeba Fragilis
(Very/tendency to) infrequent stools or normal stool frequency
Weak appetite
(Severe) abdominal discomfort
General flatulence
Conditions that suggest Parasite, Dientamoeba Fragilis
Ulcerative Colitis
DF has also been implicated as a cause of colitis in adults.
IBS (Irritable Bowel Syndrome)
Complete data of long, post treatment follow up has recently been reviewed for 21 consecutive patents who presented with at least two months to a lifelong history of IBS-like symptoms and were positive (exclusively) for Dientamoeba fragilis (DF). From our prospective study it is clear that the use of SAF fixative is crucial in the detection of DF. Also, diarrhea predominant IBS should not be diagnosed until appropriately fixed and stained stools are examined by a parasitologist experienced in DF detection. Such observations also point to the need for a larger placebo-controlled multi-centre trial in eradication of DF in patients with diarrhea-predominant IBS. Until this is carried out however, since the therapy is of short duration, has an acceptable side effect profile, and DF can lead to colitis, those patients with ongoing chronic symptoms should probably seek diagnosis and treatment for DF. [Borody TJ, Robertson C, Wettstein A, Warren E, Leis S and Surace R. (Winter 2002 Edition of Ibis News and Views, pp. 4-5]
Eosinophilia
Allergic colitis with peripheral eosinophilia secondary to DF infection has been described in medical publications.
Recommendations for Parasite, Dientamoeba Fragilis
Grapefruit / Citrus Seed Extract
Using a product called citramesia (contains grapefruit seed extract and wormwood), some have claimed a complete elimination of DF.
Antibiotics
Stool-positive ‘IBS-like’ patients underwent a combination therapy with iodoquinol and doxycycline and all became negative for DF. When interviewed at least four weeks after treatment, 16 of 21 patients reported global improvement post-treatment. After treatment with antibiotics for 16 patients with diarrhea-predominant IBS-type symptoms, 14 reported the resumption of regular bowel habit with a reduction in frequency to 1-2 stools per day and improvement in associated symptoms. Those with minor symptoms or with constipation failed to improve post-treatment suggesting another cause for their symptoms. [Borody TJ, Robertson C, Wettstein A, Warren E, Leis S and Surace R. (Winter 2002 Edition of Ibis News and Views, pp. 4-5]
Key
 | Weak or unproven link |
 | Strong or generally accepted link |
 | Strongly counter-indicative |
 | Likely to help |
Glossary
Protozoan
(Plural: Protozoa) Any one of a large group of one-celled (unicellular) animals, including amoebas. They are microorganisms that differ from bacteria in that they are larger and possess a nucleus surrounded by a membrane. Several species of protozoa can be transmitted through water and cause disease in humans, including Giardia, Cryptosporidium, Cyclospora, Entamoeba and Isospora. One distinguishing characteristic of protozoa is that when released from the human body through feces they are present in an encysted (dormant) form. These cysts have a protective layer that surrounds them and keeps chemicals from penetrating them. Therefore, chlorine disinfection does not kill the protozoan cysts.
Chronic
Usually Chronic illness: Illness extending over a long period of time.
Diarrhea
Excessive discharge of contents of bowel.
Nausea
Symptoms resulting from an inclination to vomit.
Anorexia Nervosa
An eating disorder characterized by excess control - a morbid fear of obesity leads the sufferer to try and limit or reduce their weight by excessive dieting, exercising, vomiting, purging and use of diuretics. Sufferers are typically more than 15% below the average weight for their height/sex/age and typically have amenorrhea (if female) or low libido (if male). 1-2% of female teenagers are anorexic.
Flatulence
Abnormal amount of gas in the stomach and intestines.
Colitis
Inflammation of the colon.
Asymptomatic
Not showing symptoms.
Parasite
An organism living in or on another organism.
Acute
An illness or symptom of sudden onset, which generally has a short duration.
Epidemiology
The study of the causes and distribution of disease in human populations.
Sodium
An essential mineral that our bodies regulate and conserve. Excess sodium retention increases the fluid volume (edema) and low sodium leads to less fluid and relative dehydration. The adult body averages a total content of over 100 grams of sodium, of which a surprising one-third is in bone. A small amount of sodium does get into cell interiors, but this represents only about ten percent of the body content. The remaining 57 percent or so of the body sodium content is in the fluid immediately surrounding the cells, where it is the major cation (positive ion). The role of sodium in the extracellular fluid is maintaining osmotic equilibrium (the proper difference in ions dissolved in the fluids inside and outside the cell) and extracellular fluid volume. Sodium is also involved in nerve impulse transmission, muscle tone and nutrient transport. All of these functions are interrelated with potassium.
Lumen
Space in the interior of a tubular structure.
Pruritus
Severe itching, often of undamaged skin.
Constipation
Difficult, incomplete, or infrequent evacuation of dry, hardened feces from the bowels.
Tenesmus
Tenesmus is the constant feeling of the need to empty the bowel or bladder, accompanied by pain, cramping, and involuntary straining efforts.
Irritable Bowel Syndrome
(IBS) A condition that causes upset intestines for a long period of time. It is very unpleasant to the sufferer but tends to be harmless and usually does not lead to more serious complaints. The symptoms vary from person to person and from day to day. In order to be diagnosed with IBS, a person must have at least three of the following symptoms: pain in the lower abdomen; bloating; constipation; diarrhea or alternating diarrhea and constipation; nausea; loss of appetite; tummy rumbling; flatulence; mucous in stools; indigestion; constant tiredness; frequent urination; low back pain; painful intercourse for women.
