- Parasites that are commonly found in the intestinal flora of humans.
- Molecular studies have documented numerous genotypes, including usually zoonotic organisms, so B. hominis infection in humans is likely more heterogeneous than suspected.
- Global presence is found also in animals, e.g., swine.
- Appears as a thick-walled cyst (6-40 μm) in human feces [Fig].
- Taxonomic classification is unclear. Based on RNA molecular analysis, B. hominis has been labeled as a stramenopile, similar to a large grouping of one and multi-celled protists such as algae, diatoms and slime molds. Confusion genomically also furthered as the organism has both a nuclear genome and organelle genome.
- B. hominis was historically used to denote infection, but likely a more diverse group of Blastocystis causes human infection.
- Suggest due to diversity, probably refer to Blastocystis spp. or Blastocystis spp. subtype n (n= subtype number, Stensvold classification).
- The lifecycle is not well understood; likely transmission through fecal-oral routes, with contaminated water a high suspect. Cysts may infect epithelial cells of the GI tract.
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