Blastocystis hominis is a common microscopic parasitic organism found throughout the world. Watery or loose stools, diarrhea, abdominal pain, anal itching, weight loss, and excess gas have all been reported in persons with Blastocystis infection.
Many people have no symptoms at all.
Blastocystis can remain in the intestines for weeks, months, or years. It is hard to be sure, and experts disagree on this point. Whether or not B. hominis is the primary cause of your symptoms is unknown. Finding Blastocystis in stool samples should be followed up with a careful search for other possible causes of your symptoms. Symptoms may be caused by infection with other parasitic organisms, bacteria, or viruses.