Blastocystis - Signs and Symptoms

Signs and Symptoms

Most published studies have reported that between 50% and 80% of individuals mono-infected with Blastocystis will show symptoms. Factors influencing presentation of symptoms have been listed as the patient's age, with younger patients less likely to show symptoms, as well genetic changes that influence the production of cytokines. Some studies have suggested that pathogenicity may be linked to specific subtypes of Blastocystis and experimental infection of animals has reported varying degrees of illness depending on the subtype used. While some subtypes appear to be less likely to result in symptomatic infection, those subtypes are also found in symptomatic individuals who have no other infection found. Symptoms associated with the infection are diarrhea, nausea, abdominal cramps, bloating, excessive gas, and anal itching. Most cases of the infection appear to become diagnosed as irritable bowel syndrome, according to studies from Denmark, Pakistan, the United Kingdom, and Italy. The timescale of infection with the parasite can range from weeks to years.