Blastocystis

Blastocystis is a genus of single-celled parasitic organisms known to infect humans and a wide range of animals. The organism is a member of the Stramenopiles, a diverse group of eukaryotic microbes. Blastocystis is notable for its potential role in human disease, although its pathogenicity remains controversial among medical professionals.

Morphology[edit | edit source]

Blastocystis exhibits a variety of morphological forms in culture and in fecal samples. The most commonly observed form is the vacuolar (or granular) form, which is spherical in shape and measures 2-15 µm in diameter. Other forms include the amoeboid, cyst, and avacuolar forms.

Life Cycle[edit | edit source]

The life cycle of Blastocystis is not completely understood. It is believed that the cyst form is the infectious stage, which is ingested by the host through contaminated food or water. Once inside the host, the cyst transforms into the other forms.

Pathogenicity[edit | edit source]

The pathogenicity of Blastocystis is a subject of ongoing debate. Some individuals infected with the organism exhibit no symptoms, while others develop a range of gastrointestinal symptoms such as diarrhea, abdominal pain, and bloating. It is unclear whether these symptoms are directly caused by Blastocystis or are the result of an overreaction of the host's immune system.

Diagnosis and Treatment[edit | edit source]

Diagnosis of Blastocystis infection is typically made by identifying the organism in stool samples using microscopy. Treatment is usually with antiprotozoal drugs, although the effectiveness of these drugs can vary.

Epidemiology[edit | edit source]

Blastocystis is found worldwide, with higher prevalence rates in developing countries. It is often found in individuals who have traveled to these countries, as well as in individuals with compromised immune systems.

File:Blastocystis hominis.jpg

Blastocystis hominis seen through a microscope