Blastocystis spp.: the role in human somatic pathology

In recent years, the role of pathogens of infectious and parasitic diseases in human somatic pathology has been increasingly discussed. Blastocysts belong to the most common intestinal protozoa, but their role in intestinal parasitosis, as well as in some somatic diseases, is still poorly understood. An important question remains about the pathogenic potential of Blastocystis spp. because the parasite is detected in patients with symptoms and in asymptomatic carriers. At the same time, recent researches have shown a link between blastocyst invasion and various forms of gastrointestinal (GI) dysfunction, primarily irritable bowel syndrome (IBS), as well as skin manifestations, such as urticaria. The main method used for the clinical diagnosis of blastocyst invasion remains microscopy, which, despite the intensive development of immunological and molecular genetic methods of diagnosis, is often not only the first, but also a sufficient stage of research. Stating from the year 2000, in Ukraine the reporting forms list the cases of Blastocystis spp. detection during parasitological surveys of the population, but the blastocystosis morbidity has not being registered. In general, the frequency of detection of Blastocystis spp. in the population of Ukraine corresponds to the prevalence of the pathogen in developed countries — the average long‑term indicator for 2009 — 2018 was 4.4 per 100 thousand population. The results of our own research indicate a higher frequency of detection of Blastocystis spp. among the adult population of Ukraine, mainly in patients with gastrointestinal diseases. During the examination of healthy adults, Blastocystis spp. was detected in 5.2 ± 0.8 %, in patients with chronic gastrointestinal tract lesions — 20.5 ± 6.5 %, including the cases among patients diagnosed with IBS — 28.6 ± 9.9 %. All IBS patients with detected Blastocystis spp. demonstrated dysbiotic disorders of the 1 or 2 degrees.