About Blastocystis hominis str. Singapore isolate B (sub-type 7)

Blastocystis is a genus of single-celled heterokont parasites belonging to a group of organisms that are known as the Stramenopiles (also called Heterokonts) that includes algae, diatoms, and water molds. Blastocystis consists of several species, living in the gastrointestinal tracts of species as diverse as humans, farm animals, birds, rodents, reptiles, amphibians, fish, and cockroaches. In less developed areas, infection rates as high as 100% have been observed. High rates of infection are found in individuals in developed countries who work with animals. The paper attributed confusion over pathogenicity to the existence of asymptomatic carriers, a phenomenon the study noted is common to all gastrointestinal protozoa. However, Blastocystis has never fulfilled Koch's postulate that infection of a healthy individual with Blastocystis leads to disease. The fact that Blastocystis' infection route is oral-anal indicates that carriers have been in contact with faecal contaminated matter which might have included other intestinal pathogens that explain the observed symptoms. A more likely explanation is the presence of virulent and non-virulent strains as there exists and enormous genetic variation between different strains (or genotypes). See the genotype paper by Rune Stensvold and the recent Blastocystis genome paper expanding on this diversity. An alternative theory that Blastocystis is not a pathogen at all has recently been strengthened based on its biochemistry.

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Taxonomy ID 12968

Data source Genoscope - Institut de Genomique - CEA

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