It is a pleomorphic, strict anaerobic and enteroparasitic unicellular protozoan with a high worldwide prevalence.
Certain forms of Blastocystis hominis may be more likely to be related to symptoms of an infection .
Sometimes Blastocystis simply lives in a person’s digestive tract without causing harm.
Infections caused by Blastocystis hominis usually go away on their own.
Risk factors for Blastocystis hominis infection
Some risk factors for Blastocystis hominis infection include:
- Consume water or ice that is contaminated with the parasite. The most common sources of contaminated water include poorly maintained streams, rivers, lakes, and wells.
- Consume food that has had contact with contaminated water.
- Travel to countries with low sanitation standards.
- Have close contact with infected people
- Not cleaning children with diapers properly or regularly.
- Swimming in potentially contaminated water
- Contact with feces through sexual activities.
Causes of Blastocystis hominis infection
The mode of entry of Blastocystis hominis into the digestive system is not fully understood.
The most popular theory of experts is that infection occurs by ingesting the parasite through dirty water or unwashed food that has been in contact with infected feces.
The parasite exists in a hard, shell-shaped case called a cyst. These cysts have been found in the feces of infected individuals.
Ingestion of Blastocystis hominis cysts causes the organism to begin to multiply asexually.
New cysts then form and leave the body of an infected individual during defecation.
Signs and symptoms of Blastocystis hominis infection
Many people with Blastocystis hominis infection do not show signs and symptoms of infection.
The parasite can be present in healthy and asymptomatic individuals.
In case of symptoms, those that may be associated with Blastocystis hominis infection include:
- Nausea and fatigue
- Loss of appetite
- Bloating, excessive gas (flatulence).
- Abdominal cramps
- Hives or other skin rashes.
- Joint pain
- Constipation and greasy stools that float.
- Diarrhea .
Symptoms can start and last for any length of time after an infection.
Diagnosis of Blastocystis hominis infection
The diagnosis of Blastocystis hominis infection is made through the following tests and examinations:
- A complete physical exam and review of any travel or medical history.
- Symptom evaluation.
- Analysis of stool samples: The samples are analyzed under a microscope for the presence of cysts of Blastocystis hominis.
- The analysis may involve the submission of multiple samples in a few days.
- Blood tests, which are done mainly to rule out other causes of symptoms.
- An endoscopy , in this procedure, a tube is inserted into the mouth or rectum for analysis of the digestive tract for possible causes of symptoms.
Blastocystis hominis infection can be difficult to diagnose, as some tests can be unreliable.
Many clinical conditions can have similar signs and symptoms.
The doctor may perform additional tests to rule out other clinical conditions and arrive at a definitive diagnosis.
Complications of Blastocystis hominis infection
A major complication of Blastocystis hominis infection is dehydration, which may be due to symptoms of a chronic infection, such as diarrhea, that do not respond to treatment.
Treatment of Blastocystis hominis infection
People with Blastocystis hominis infection without symptoms do not need to undergo any treatment. However, in individuals with symptoms, treatment measures may include the following:
Medication administration including:
- Antiprotozoal drugs.
A combination of medications may be necessary, in some cases.
If medications are not effective, additional diagnostic procedures may be necessary to look for other causes of symptoms.
Prevention of Blastocystis hominis infection
Some methods to ensure prevention of Blastocystis hominis infection include:
- Practice good hygiene.
- Avoid contact of food with contaminated water.
- Peel any raw vegetables or fruits and wash them before eating.
- Avoid food from street vendors that may not be properly prepared.
- Avoid raw milk and dairy products.
- Avoid keeping moist food at room temperature.
- Do not cook with potentially contaminated water.
- Make sure to filter or boil the water for at least 3 minutes in regions where the water quality is poor due to high sanitary regulations.
- It is safer to consume canned or bottled beverages.
- Avoid swimming in potentially contaminated waters.
- Keep your mouth closed while showering.
- Use bottled water to brush your teeth, when the water may be contaminated.
- Precautions when having sexual intercourse, avoiding exposure or contact with feces during sexual activity.
- Wash hands if contact is made with the anus or rectal area.
- Use a condom if you have anal sex and wash your hands before and after handling the condom
- Use an appropriate barrier during oral or anal sex.
Prognosis of Blastocystis hominis infection
The prognosis of Blastocystis hominis infection may depend on the general health of the affected individual.
Possible outcomes of the disease include the following:
- Mild symptoms resolve on their own without treatment within a few days.
- Moderate to severe symptoms can disappear with proper treatment.
- In some cases, the infection can become chronic with digestive problems, such as diarrhea, that do not respond to treatment.
- Children are at higher risk of dehydration as a result of diarrhea than adults
Overview of Blastocystis hominis infection
Understanding the biology of Blastocystis hominis and the mechanism of how it causes symptoms in some infected people remains an area of active research.
Currently, there is no definitive evidence that Blastocystis hominis infection is the cause of any symptoms. It can be found in healthy individuals or in people who have digestive problems, such as diarrhea. Many people infected with Blastocystis hominis never have symptoms.
Blastocystis hominis has been characterized as a yeast, a fungus, a flagellate (which has the ability to move like a whip).
It has been classified as a protist. A protist is a name for a eukaryotic (non-bacterial) organism that is not a plant, animal, or fungus.
Blastocystis hominis infection is a common disease that is often associated with irritable bowel syndrome.