Blastocystis hominis: uma revisão da literatura sobre um parasito controverso

Abstract

This study conducted a literature review on the microorganism Blastocystis hominis, addressing its epidemiology, genetic diversity, diagnostic methods, and potential clinical associations. This intestinal protozoan is widely distributed, with particularly high prevalence in developing regions, where it can reach up to 60%. The analysis revealed remarkable genetic variability in the parasite, with approximately 17 subtypes identified, at least 10 of which can infect humans. This genetic diversity is associated with different clinical manifestations, ranging from asymptomatic infections to symptomatic cases, such as abdominal pain and irritable bowel syndrome. Despite its widespread distribution, the pathogenicity of B. hominis remains controversial, as the parasite is found in both healthy individuals and symptomatic patients. Diagnosis is challenging, especially due to the polymorphic nature of the microorganism, which limits the effectiveness of traditional methods such as direct fecal examination. In contrast, molecular techniques, such as polymerase chain reaction (PCR), have demonstrated greater sensitivity and accuracy, enabling subtype identification and contributing to a deeper understanding of its epidemiology. The study concludes that further research is urgently needed to clarify the mechanisms of pathogenicity and to improve diagnostic methods, particularly in areas with poor sanitation infrastructure, which disproportionately affect vulnerable populations. Research focused on advancements in this field is essential for developing effective strategies for the control, diagnosis, and treatment of Blastocystis hominis infections.