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| {{Dientamoebiasis}} | | {{Dientamoebiasis}} |
| ==Overview==
| | '''For patient information click [[{{PAGENAME}} (patient information)|here]]''' |
| '''Dientamoebiasis''' is a medical condition caused by infection with ''[[Dientamoeba fragilis]]''. ''[[Dientamoeba fragilis]]'' is a single celled parasite that infects the lower gastrointestinal tract of humans. | |
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| ==Symptoms==
| | {{CMG}} {{AE}} {{KD}} |
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| The most commonly reported symptoms in conjunction with infection with ''[[Dientamoeba fragilis]]'' include abdominal pain (69%) and diarrhea (61%). <ref name="VANDENBERG_2006">{{cite journal |author=Vandenberg O, Peek R, Souayah H, ''et al'' |title=Clinical and microbiological features of dientamoebiasis in patients suspected of suffering from a parasitic gastrointestinal illness: a comparison of Dientamoeba fragilis and Giardia lamblia infections |journal=Int. J. Infect. Dis. |volume=10 |issue=3 |pages=255-61 |year=2006 |pmid=16469517 |doi=10.1016/j.ijid.2005.05.011}}</ref> Diarrhea may be intermittent and may not be present in all cases. The degree of symptoms may vary from asymptomatic to severe <ref name="NORBERG_2003">{{cite journal |author=Norberg A, Nord CE, Evengård B |title=Dientamoeba fragilis--a protozoal infection which may cause severe bowel distress |journal=Clin. Microbiol. Infect. |volume=9 |issue=1 |pages=65-8 |year=2003 |pmid=12691546 |doi=}}</ref>, and can include weight loss, vomiting, fever, and involvement of other digestive organs. A study from Sydney Australia of 60 individuals who were found to be infected with ''[[Dientamoeba fragilis]]'' found that all had symptoms.<ref name="STARK_2005">{{cite journal |author=Stark D, Beebe N, Marriott D, Ellis J, Harkness J |title=Prospective study of the prevalence, genotyping, and clinical relevance of Dientamoeba fragilis infections in an Australian population |journal=J. Clin. Microbiol. |volume=43 |issue=6 |pages=2718-23 |year=2005 |pmid=15956388 |doi=10.1128/JCM.43.6.2718-2723.2005}}</ref> Researchers have reported that symptoms may be more severe in children. Additional symptoms reported have included: <ref name="JOHNSON_2004">{{cite journal |author=Johnson EH, Windsor JJ, Clark CG |title=Emerging from obscurity: biological, clinical, and diagnostic aspects of Dientamoeba fragilis |journal=Clin. Microbiol. Rev. |volume=17 |issue=3 |pages=553-70, table of contents |year=2004 |pmid=15258093 |doi=10.1128/CMR.17.3.553-570.2004}}</ref>
| | ==[[Dientamoebiasis overview|Overview]]== |
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| #[[Weight loss]]
| | ==[[Dientamoebiasis historical perspective|Historical Perspective]]== |
| #[[Fatigue]]
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| #[[Nausea]] and [[vomiting]]
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| #[[Fever]]
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| #Uritcaria (skin rash)
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| #[[Pruritis]] (itchiness)
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| #Biliary infection
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| ==Transmission== | | ==[[Dientamoebiasis pathophysiology|Pathophysiology]]== |
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| Parasites similar to ''[[Dientamoeba fragilis]]'' are transmitted by consuming water or food contaminated with feces. Organisms similar to ''[[Dientamoeba fragilis]]'' are known to produce a cyst stage which is able to survive outside of the host and facilitate infection of new hosts. However, the exact manner in which ''[[Dientamoeba fragilis]]'' is transmitted is not yet known, as scientists have reported that the organism is unable to survive outside its human host for more than a few hours after excretion, and no cyst stage has been found. <ref name="LAGACE_2006">{{cite journal |author=Lagacé-Wiens PR, VanCaeseele PG, Koschik C |title=Dientamoeba fragilis: an emerging role in intestinal disease |journal=CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne |volume=175 |issue=5 |pages=468-9 |year=2006 |pmid=16940260 |doi=10.1503/cmaj.060265}}</ref>
| | ==[[Dientamoebiasis causes|Causes]]== |
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| Early theories of transmission suggested that ''[[Dientamoeba fragilis]]'' was unable to produce a cyst stage in infected humans, but some animal existed that in which it did produce a cyst stage, and this animal was responsible for spreading it. However, no such animal has ever been discovered. <ref name="JOHNSON_2004" /> A later theory suggested the organism was transmitted by pinworms, which provided protection for the parasite outside of the host. However recent study has failed to show any association between ''[[Dientamoeba fragilis]]'' infection and pinworm infection. <ref name="LAGACE_2006" />
| | ==[[Dientamoebiasis differential diagnosis|Differentiating Dientamoebiasis from other Diseases]]== |
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| ==Diagnosis== | | ==[[Dientamoebiasis epidemiology and demographics|Epidemiology and Demographics]]== |
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| Diagnosis is usually performed by submitting a stool sample for examination by a parasitologist in a procedure known as an Ova and Parasite (O&P) Examination.
| | ==[[Dientamoebiasis risk factors|Risk Factors]]== |
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| The failure of routine O&P examination to identify ''[[Dientamoeba fragilis]]'' infection has been noted:
| | ==[[Dientamoebiasis natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| | | ==Diagnosis== |
| #One researcher investigated the phenomenon of symptomatic relapse following treatment of infection with ''[[Dientamoeba fragilis]]'' in association with its apparent disappearance from stool samples. The study found that the organism could still be detected in patients through [[colonoscopy]] or by examining stool samples taken in conjunction with a saline laxative. <ref name="pmid4317789">{{cite journal |author=Steinitz H, Talis B, Stein B |title=Entamoeba histolytica and Dientamoeba fragilis and the syndrome of chronic recurrent intestinal amoebiasis in Israel |journal=Digestion |volume=3 |issue=3 |pages=146-53 |year=1970 |pmid=4317789 |doi=}}</ref>
| | [[Dientamoebiasis history and symptoms| History and Symptoms]] | [[Dientamoebiasis physical examination | Physical Examination]] | [[Dientamoebiasis laboratory findings|Laboratory Findings]] |
| #A study found that trichrome staining, a traditional method for identification, had a sensitivity of 36% (9/25) when compared to stool culture. <ref name="pmid12866914">{{cite journal |author=Windsor JJ, Macfarlane L, Hughes-Thapa G, Jones SK, Whiteside TM |title=Detection of Dientamoeba fragilis by culture |journal=Br. J. Biomed. Sci. |volume=60 |issue=2 |pages=79-83 |year=2003 |pmid=12866914 |doi=}}</ref>
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| #An additional study found that the sensitivity of staining was 50% (2/4), and that the organism could be successfully cultured in stool specimens up to 12-hours old which were kept at room temperature. <ref name="pmid8337717">{{cite journal |author=Sawangjaroen N, Luke R, Prociv P |title=Diagnosis by faecal culture of Dientamoeba fragilis infections in Australian patients with diarrhoea |journal=Trans. R. Soc. Trop. Med. Hyg. |volume=87 |issue=2 |pages=163-5 |year=1993 |pmid=8337717 |doi=}}</ref>
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| ==Medical acceptance and misdiagnosis==
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| Researchers have noted that physicians in many countries have been slow to address infection with ''[[Dientamoeba fragilis]],'' despite the body of clinical literature that links it with symptoms. <ref name="JOHNSON_2004" /> Early microbiologists reported that the organism was not pathogenic, even though six of the seven individuals from whom they isolated it were experiencing symptoms of dysentary. Their report, published in 1918, concluded the organism was not pathogenic because it consumed bacteria in culture, but did not appear to engulf red blood cells was seen in the most well known disease causing amoeba of the time, ''[[Entamoeba histolytica]].'' This initial report may still be contributing to the reluctance of physicians to diagnose the infection. <ref name="JOHNSON_2004" />
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| An Australian study identified a large number of patients considered to have [[Irritable bowel syndrome]] who were actually infected with ''[[Dientamoeba fragilis]].'' <ref name="BORODY_2002">{{cite journal |author=Borody T, Warren E, Wettstein A, et al. | title = Eradication of Dientamoeba fragilis can resolve IBS-like symptoms.
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| | journal=J Gastroenterol Hepatol | year= 2002 | volume=17 | issue=Suppl; pages=A103}}</ref> Symptoms resolved following treatment.
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| ==Genetic diversity==
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| A study of ''[[Dientamoeba fragilis]]'' isolates from 60 individuals with symptomatic infection in Sydney Australia found that all were infected with the same genotype. <ref name="STARK_2005" />
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| ==Prevalence==
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| Although ''[[Dientamoeba fragilis]]'' has been described as an infection that is "emerging from obscurity," <ref name="JOHNSON_2004" />it has become one of the most prevalent gastrointestinal infections in industrialized countries, especially among children and young adults. A Canadian study reported a prevalence of approximately 10% in boys and girls aged 11-15 years, <ref name="LAGACE_2006" />, a prevalence of 11.5% in individuals aged 16-20, and over 20 had a lower incidence of 0.3%-1.9%.
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| ==Differential Diagnosis of Dientamoebiasis==
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| {|style="width:80%; height:100px" border="1"
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| |style="height:100px"; style="width:25%" border="1" bgcolor="LightSteelBlue" | '''Cardiovascular'''
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| |style="height:100px"; style="width:75%" border="1" bgcolor="Beige" | No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Chemical / poisoning'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Dermatologic'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Drug Side Effect'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Ear Nose Throat'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Endocrine'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Environmental'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Gastroenterologic'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Genetic'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Hematologic'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Iatrogenic'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Infectious Disease'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Musculoskeletal / Ortho'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Neurologic'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Nutritional / Metabolic'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Oncologic'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Opthalmologic'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Overdose / Toxicity'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Psychiatric'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Pulmonary'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Renal / Electrolyte'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Rheum / Immune / Allergy'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Trauma'''
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| |bgcolor="Beige"| No underlying causes
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| |-bgcolor="LightSteelBlue"
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| | '''Miscellaneous'''
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| |bgcolor="Beige"| No underlying causes
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| |}
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| ==Treatment== | | ==Treatment== |
| | | [[Dientamoebiasis medical therapy|Medical Therapy]] | [[Dientamoebiasis primary prevention|Primary Prevention]] |
| Successful treatment of the infection with Iodoquinol, Doxycycline, Metronidazole, Paromomycin, and Secnidazole have been reported. <ref name="JOHNSON_2004" /> <ref name="NORBERG_2003" />
| | ==Case Studies== |
| | | [[Dientamoebiasis case study one|Case#1]] |
| ==References== | |
| {{reflist|2}}
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| ==External links== | | ==External links== |
| * http://www.dpd.cdc.gov/dpdx/HTML/Dientamoeba.htm | | * http://www.dpd.cdc.gov/dpdx/HTML/Dientamoeba.htm |
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| {{Protozoal diseases}} | | {{Protozoal diseases}} |