Dientamoeba fragilis PCR test for primates

Dientamoeba fragilis is a single-celled protozoan parasite that infects the human gastrointestinal tract and can also infect pigs, primates and other mammals. It is a flagellated protozoan closely related to trichomonads, and unlike many intestinal parasites, it lacks a cyst stage, existing only in its trophozoite form. This organism is found worldwide; its prevalence can be from 0% to over 80% depending on the geographic location, group studied, and diagnostic methods used.

It is debated whether this parasite is a harmless commensal or a mild pathogen. Studies have shown that this parasite is frequently detected in both symptomatic and asymptomatic individuals, with prevalence rates varying widely (0.2%–19% in general populations, but higher in specific groups like children in day care). Symptoms associated with this parasite, such as abdominal pain, diarrhea, bloating, and fatigue, are non-specific and can overlap with those of many other gastrointestinal conditions, making causation hard to establish. Additionally, D. fragilis does not invade tissues, lacks a cyst stage for easy transmission or survival outside the host, and is often found alongside other potential pathogens like pinworms (Enterobius vermicularis) or Blastocystis parasites, which could be the true culprits behind symptoms. Furthermore, antibody prevalence in healthy populations is very high, and carriers of this parasite do not seem to develop any chronic complications. These findings tend to support this parasite being a commensal.

D. fragilis spreads primarily through the fecal-oral route, often via contaminated food, water, or close contact with infected individuals. It may also be transmitted through pinworm eggs (Enterobius vermicularis), as the two parasites frequently co-infect (Girginkardeşler et al., 2008). Effective hygiene practices such as handwashing and proper sanitation are key to prevention.

Diagnosis is often by microscopic examination of fecal smears. However, the sensitivity and specificity of this method are low because the parasite is almost invisible in stool and is very fragile. PCR is increasingly being used to replace traditional methods, due to its high sensitivity and specificity (Stark et al., 2006; Tolba et al., 2022).

Utilities:

Help confirm the disease causing agent
Environmental monitoring
Help ensure that individual mammals are free of this parasite
Early prevention of spread of this parasite in herds and animal facilities
Minimize human exposure to this parasite
Safety monitoring of biological products and vaccines that derive from susceptible mammals

References:
Girginkardeşler N, Kurt O, Kilimcioğlu AA, Ok UZ. Transmission of Dientamoeba fragilis: evaluation of the role of Enterobius vermicularis. Parasitol Int. 2008 Mar;57(1):72-5.

Stark D, Beebe N, Marriott D, Ellis J, Harkness J. Evaluation of three diagnostic methods, including real-time PCR, for detection of Dientamoeba fragilis in stool specimens. J Clin Microbiol. 2006 Jan;44(1):232-5.

Tolba MM, Allam AF, Khalil SS, Elshouki WM, Shehab AY. Evaluation of microscopy and PCR for detection of Dientamoeba fragilis. Trop Parasitol. 2022 Jul-Dec;12(2):87-93.

Specimen requirements: 0.2 ml feces or fecal swab, or environmental swab, or 0.2 ml cell culture.

Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative real time PCR

Normal range: Nondetected