Signs & Symptoms of Dientamoeba fragilis

Some people infected with Dientamoeba fragilis remain asymptomatic, meaning that they do not present any symptom at all. As the actual prevalence of this parasite is still unknown, it is not possible at the moment to assess the real percentage of asymptomatic carriers in the general population. Furthermore, there are still a lot of mysteries about the mechanisms allowing the actual clearance of this parasite in the asymptomatic people. However, some people could also present many gastrointestinal symptoms, ranging from mild to severe depending of the cases. Taking all those previous facts together, it has been suggested that some specific genetic variants of Dientamoeba fragilis could always be non-pathogenic for human, meaning that the person’s immune system will fight successfully the parasite without the apparition of any symptom at all, while other genetic variants could be able to cause an actual infectious disease. However, this interesting hypothesis has not been proven yet.

When symptoms do occur, the gastrointestinal disease caused by this parasite is called dientamoebiasis. It is important to note that, in human, this parasite is only able to infect the large intestine and it is not able to spread to other parts of the body. The two most common symptoms are diarrhoea and abdominal pain occurring in more than 60% of the symptomatic infections. Diarrhoea is not always present and can happen intermittently over the course of more than two weeks. Other commonly seen symptoms also include weight loss, nausea, vomiting and fever. Other reported although not common symptoms are fatigue, skin rash, itchiness and concomitant biliary infection.

It is important to note that some studies have suggested that the previously mentioned symptoms may be more severe in children than in adults. Furthermore, it should be important to consult a doctor if those symptoms last for a long period, especially in children, as it has been hypothesise that chronic infection with Dientamoeba fragilis is susceptible to cause a failure to thrive.

Some scientific studies have also suggested that infection with Dientamoeba fragilis could be one of the multiple causes of the traveller’s diarrhoea. Furthermore, it has been suggested that this parasite can cause chronic infection and could then be one of the causes of some chronic symptoms, such as chronic abdominal pain or chronic fatigue. As such, consulting your healthcare professional in order to get tested and eventually treated could be a good idea if you are experiencing one of them. Those chronic gastrointestinal symptoms are also susceptible to lead to a false diagnosis of chronic gastrointestinal diseases in some cases, especially because infections with Dientamoeba fragilis are still difficult to diagnose with the currently used laboratory methods. For instance, in some cases, symptoms caused by an infection with Dientamoeba fragilis are mimicking the ones experienced by people suffering from the irritable bowel syndrome. This fact is susceptible to lead to a false diagnosis of irritable bowel syndrome for patients actually infected by Dientamoeba fragilis. In those particular cases, successful treatment of the infection caused by Dientamoeba fragilis usually resolves the symptoms mimicking the irritable bowel syndrome. As such, it should be interesting to test people allegedly suffering from the irritable bowel syndrome and other chronic gastrointestinal diseases with the right diagnostic tools in order to rule out a possible involvement of this parasite. It is important to mention here that it is not all chronic gastrointestinal diseases that are caused by this parasite and that the actual number of infections with Dientamoeba fragilis mistakenly diagnosed as chronic gastrointestinal disease is still unknown.

Finally, it is interesting to note that, even though Dientamoeba fragilis had long been considered as non-pathogenic, meaning that physicians did not believe that this parasite was able to cause an actual disease, increasing evidences have shown that Dientamoeba fragilis can indeed cause a real gastrointestinal disease in some circumstances. Furthermore, some infections with this parasite can be falsely attributed to some chronic gastrointestinal diseases, but the actual extent of those false diagnostics is still unknown. As such, more research is still needed in order to better understand the involvement of this parasite in patients that has been diagnosed with some chronic gastrointestinal diseases. Better specific diagnostic tools are also needed in order to assess the actual extent of this parasitic infection.