The pathogenic role of Blastocystis has not been proven, particularly in immunocompetent individuals. Recent data shows the overall prevalence in a local test population to be 17%. Individuals may be colonised with this organism and do not need treatment. It can be acquired by contact with animals including pets or contaminated water. Potentially pathogenic or animal strains cannot be differentiated by the current available tests. Screening for clearance of the organism or testing of family members is not recommended.
The pathogenic role of Dientamoeba has not been established either. Recent data shows the overall prevalence in local population to be 16.2% with more than 50% of children aged 5-10 testing positive. A randomised double blinded placebo controlled clinical trial does not support routine metronidazole treatment for children with chronic gastrointestinal symptoms with this organism. Treatment may be harmful resulting in unnecessary adverse reactions, disruption of the normal gut flora and contribute to the development of anti microbial resistance of faecal microbiota. Screening for clearance or testing of asymptomatic family members is not recommended.
For individuals with chronic abdominal symptoms, other causes for symptoms should be considered and investigated accordingly if required.