What is Blastocystis hominis infection?
Blastocystis hominis is a microscopic organism that may be found in the stools of healthy people who aren’t having any digestive symptoms. Blastocystis hominis is also sometimes found in the stools of people who have diarrhea, abdominal pain or other gastrointestinal problems.
Researchers don’t yet fully understand the role that Blastocystis hominis plays, if any, in causing an infection. Certain forms of Blastocystis hominis may be more likely to be linked to an infection with symptoms. Sometimes, blastocystis simply lives in a person’s digestive tract without causing harm.
A Blastocystis hominis infection usually clears up on its own. There are no proven treatments for these infections. But, if your symptoms don’t get better, your doctor may recommend trying certain medications.
How common is Blastocystis hominis infection?
Blastocystis hominis infection is quite common. Please discuss with your doctor for further information.
What are the symptoms of Blastocystis hominis infection?
The common symptoms of Blastocystis hominis infection are:
There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.
When should I see my doctor?
If you have any signs or symptoms listed above or have any questions, please consult with your doctor. Everyone’s body acts differently. It is always best to discuss with your doctor what is best for your situation.
What causes Blastocystis hominis infection?
Once thought to be a harmless yeast, blastocystis is a parasite — a microscopic single-celled organism (protozoan). Many protozoans normally inhabit your gastrointestinal tract and are harmless or even helpful; others cause disease.
Whether blastocystis is the type of protozoa that causes disease is controversial. While many people who carry blastocystis have no signs or symptoms, the organism is also found in people who have diarrhea and other digestive problems. Blastocystis often appears with other organisms, so it’s not clear whether it causes disease on its own or is an innocent bystander.
It’s also possible that some people may be carriers of blastocystis. These carriers don’t have any signs or symptoms of infection. And, the incidence of symptoms doesn’t go up with an increase in the number of parasites.
Although no one knows for sure how blastocystis gets into the digestive system, experts suspect that blastocystis may get into the intestinal tract through oral-fecal contact. This can occur when a person doesn’t wash his or her hands thoroughly after using the toilet before preparing food. The prevalence of blastocystis increases in places with inadequate sanitation and poor personal hygiene.
What increases my risk for Blastocystis hominis infection?
Blastocystis is common, and anyone can have the organism in his or her stools. You may be at higher risk if you travel or live where sanitation is inadequate or where the water may not be safe.
Diagnosis & treatment
The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.
How is Blastocystis hominis infection diagnosed?
The cause of your diarrhea may be difficult to diagnose. Even if blastocystis is present on a fecal exam, it may not be causing your symptoms.
Your doctor likely will take your medical history, ask you about recent activities, such as traveling, and perform a physical exam. A number of lab tests help diagnose parasitic diseases and other noninfectious causes of gastrointestinal symptoms:
- Stool (fecal) exam. This test looks for parasites or their eggs (ova). Your doctor may give you a special container with preservative fluid for your stool samples. Refrigerate — don’t freeze — your samples until you take them to your doctor’s office or lab.
- If you have symptoms, but the fecal exam doesn’t reveal the cause, your doctor may request this test. After you’re sedated, a doctor, usually a gastroenterologist, inserts a tube into your mouth or rectum to look for the cause of your symptoms. You’ll need to fast beginning the night before the test.
- Blood tests. A blood test that can detect blastocystis is now available, but it isn’t commonly used. However, your doctor may order blood tests to look for other causes of your signs and symptoms.
How is Blastocystis hominis infection treated?
If you have blastocystis without signs or symptoms, then you don’t need treatment. Mild signs and symptoms may improve on their own within a few days.
Potential medications for treating blastocystis infection include:
- Antibiotics, such as metronidazole (Flagyl) or tinidazole (Tindamax)
- Combination medications, such as sulfamethoxazole and trimethoprim (Bactrim, Septra, others)
- Antiprotozoal medications, such as paromomycin, or nitazoxanide (Alinia)
However, keep in mind that response to medication for blastocystis infection varies greatly from person to person. And, because the symptoms you’re having might be unrelated to blastocystis, it’s also possible that any improvement may be due to the medication’s effect on another organism.
Lifestyle changes & home remedies
What are some lifestyle changes or home remedies that can help me manage Blastocystis hominis infection?
The following lifestyles and home remedies might help you cope with Blastocystis hominis infection:
- Wash your hands with soap and warm water after using the toilet, changing diapers, and before handling food.
- Teach children the importance of washing hands to prevent infection.
- Avoid water or food that may be contaminated.
- Wash and peel all raw vegetables and fruits before eating.
- When traveling in countries where the water supply may be unsafe, avoid drinking unboiled tap water and avoid uncooked foods washed with unboiled tap water. Bottled or canned carbonated beverages, seltzers, pasteurized fruit drinks, and steaming hot coffee and tea are safe to drink.
If you have any questions, please consult with your doctor to better understand the best solution for you.
Hello Health Group does not provide medical advice, diagnosis or treatment.
Review Date: September 7, 2017 | Last Modified: December 8, 2019
Blastocystis spp. FAQs. https://www.cdc.gov/parasites/blastocystis/faqs.html. Accessed September 7, 2017.
Blastocystis hominis infection. http://www.mayoclinic.org/diseases-conditions/blastocystis-hominis-infection/home/ovc-20169153. Accessed September 7, 2017.