Amebiasis is a parasitic infection of the intestines caused by Entamoeba histolytica.

It is common in tropical regions of the world where the condition of the sewage system is poor, allowing the exposure of drinking water, food and consumables to faecal contamination.

The disease occurs frequently in tropical areas of the world with insufficient density of sewage network.

At greatest risk of getting sick are:

• People who have traveled to tropical countries with poor public hygiene;
• Immigrants from tropical areas with poor sanitary conditions;
• People living in institutions with poor sanitary conditions;
• Men , who have sex with persons of the same sex;
• People with a weakened immune system or other diseases;

What are the symptoms?

Clinical manifestations usually occur within 1-4 weeks of ingestion of the cysts. Only about 10-20% of infected people get sick from the presence of the amoeba in their body.

Symptoms in this initial stage of infection are mild, such as diarrheal stools and stomach cramps.
If the parasite penetrates the lining of the intestine, it is possible to cause amoebic dysentery.

This is a more dangerous form of the disease, characterized by increased frequency of bowel movements with bloody and watery stools and severe stomach discomfort.

If the protozoa enters the bloodstream, it is possible for it to enter the liver, heart and lungs, where it can cause tissue destruction and abscesses.

Often the parasite invades the liver. Symptoms of amoebic liver disease are fever and severe tenderness in the right upper quadrant of the torso.

What are the causes?

Entamoeba histolytica are unicellular protozoa that enter the human body mainly by ingesting cysts from contaminated food or water.

It can also enter the body through direct contact with faeces. The cysts are a relatively inactive form of the parasite that can live for several months in the soil or environment in which faeces have been passed.

Microscopic cysts are found in faecal-contaminated soil, manure or water. They can also be transmitted by workers producing food products. Infection can occur during anal sex or during an enema.

When the cysts enter the body, they penetrate the walls of the organs of the digestive tract, where they release the invasive form of the helminth, called a trophozoite.

Parasites reproduce in the digestive tract and migrate to the large intestine, where they usually begin to attach to its wall and possibly disrupt its integrity by causing bloody diarrhea, colitis, and even destroy it completely.

Once the trophozoites have breached the wall of the large or small intestine, they can enter the bloodstream and through it reach various internal organs.

If they enter these organs they can cause abscesses, infections, severe illness and even death.

The life cycle of the amoeba is considered complete when the host begins to shed new cysts into the environment after infecting its feces with cysts.

Treatment of amebiasis

Treatment in uncomplicated cases usually consists of 10 days of oral metronidazole. A doctor may prescribe medication to control nausea if the sufferer is unable to keep food and medication down without vomiting.

If the parasite has invaded the intestinal tissues or the invasion has covered the whole body, the treatment should be aimed at healing all the damage that has been done.

The protozoan is sensitive to metronidazole and complete cure in uncomplicated cases occurs after about 2 weeks.

However, if it has penetrated the internal organs, the prognosis for patients is good as long as they receive appropriate medical treatment. If left untreated, the disease is fatal.

Every year around 70,000 people die from it worldwide.


Maintaining good personal hygiene is the best way to prevent this potentially deadly disease:

• Wash your hands thoroughly with soap and water after using the toilet and before handling food;

• Thoroughly wash fruits and vegetables before consumption by you or your family;

• Avoid eating fruits and vegetables that you have not personally washed or peeled;

• It is recommended to drink only bottled water and soft drinks if you go to places where there is no sewage network. Although in Bulgaria the activity of the Regional Health Inspections is very well regulated and prescriptions are issued in a timely manner, and the media also raise the alarm when the water in a populated place in the country is unfit for drinking;

• If you still have doubts about the quality of drinking water, you can boil it before using it or put half an iodine tablet per 1 liter;

• Avoid using ice cubes unless you have made them yourself in your refrigerator or freezer and with water that you know is safe to drink.

• Avoid milk, cheese or other unpasteurized dairy products;

• Do not buy food sold by street vendors;

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