Blastocystis Hominis

Diagnosis of Blastocystis Infection

Diagnosing Blastocystis infection can be challenging because the organism may not always cause symptoms. Often, another food- or water-borne cause is responsible.

• Medical History and Physical Exam: Your doctor will ask about:

  • Recent travel or activities

  • Dietary habits

  • Onset and pattern of symptoms

• Stool (Fecal) Exam:

  • Checks for parasites in your stool

  • Your doctor may provide a container with preservative fluid

  • Refrigerate samples until delivery to the lab; do not freeze

• Endoscopy:

  • Recommended if stool tests are inconclusive

  • Uses a camera on a tube under sedation to examine your digestive tract

• Blood Tests:

  • A specific test can detect Blastocystis, but it’s not commonly used

  • Blood tests may also help identify other causes of gastrointestinal symptoms

Treatment of Blastocystis Infection

Not all Blastocystis infections require treatment.

• No Symptoms: If you are asymptomatic, treatment is usually unnecessary.

• Mild Symptoms: Often improve on their own within a few days.

• Medications: Used if symptoms are persistent or severe:

  • Antibiotics: Metronidazole (Flagyl) or tinidazole (Tindamax)

  • Combination Antibiotics: Sulfamethoxazole and trimethoprim (Bactrim, Septra)

  • Anti-protozoal Medications: Paromomycin or nitazoxanide (Alinia)

• Important Note: Response to medications varies. Symptom improvement may sometimes be due to the effect on other organisms rather than Blastocystis itself.