Amoebiasis: Symptoms, Diagnosis, and Treatment

Amoebiasis Symptoms, Diagnosis Treatment

What is Amoebiasis?


Amoebiasis Amoebiasis is a parasitic infection that targets the intestines of the body. It can affect humans in any age group. The infection is most prevalent in developing countries and areas with poor sanitation or lack of food and water hygiene.

Majority of infected people show no symptoms. Unfortunately for other patients, the infection may lead to abdominal pain, bloody diarrhea, and fever. Amoebiasis is highly contagious and kills more than 55,000 people globally each year.

Cause and Transmission of Amoebiasis

What causes Amoebiasis?

It is caused by the anaerobic parasite Entamoeba hystolytica. They are called trophozoites while living in the large intestines of the host body. Once excreted along with loose feces, they do not remain alive for long.

Inside the body, some trophozoites become cysts and enter the dormant stage. They are present in hard stools of infected people. Unlike trophozoites, cysts thrive for a few months outside the host body. They remain in the soil, water, or in sewerage.

How is Amoebiasis transmitted?

The infection can be transmitted when humans consume food or water contaminated with cysts.

For example, vegetables grown in places that use infected human feces as fertilizers become infected as well. Unsanitary preparations of food and drinks also lead to the spread of the infection.

The parasites can also be transmitted when people eat with improperly washed hands that had just come into contact with infected feces. This is very common in children or even adults in developing places where there is very poor sanitation.

Another form of transmission is thru sexual contact with an infected person. Finally, rats and cockroaches may also aid in the spread of fecal matter containing cysts.

What happens when cysts enter the body?

Cysts undergo the process of encystation once they enter the small intestine. Through this, they transform into trophozoites and become active in the large intestine.

Trophozoites feed on bacteria and food particles near the mucus layer of the large intestine. By doing this, they release enzymes which damage the epithelial cells. This ultimately leads to tissue destruction and symptoms will start showing.

Signs and Symptoms of Amoebiasis

Majority of people with Entamoeba hystolitica in their bodies show no symptoms of infection. They are asymptomatic.

Only about 10% of people infected actually experience symptoms. These usually show in 1 to 4 weeks upon being infected. However, it may also take months or even years in some cases.

Mild Symptoms

  • Painful bowel movement
  • Loose bowel movement (more than 3 days)
  • Loss of appetite
  • Fatigue

Progressive Symptoms

  • Vomiting
  • Unexpected Weight Loss
  • Fever
  • Stomach pains or abdominal cramps
  • Bloody diarrhea

Severe Cases

  • Colitis (swelling of the colon)
  • Fever and chills due to Liver Abscess
  • Skin Lesions

Complications of Amoebiasis


Gastrointestinal bleeding

This happens when parasites invade the large intestines. Bleeding occurs as they start damaging the cells and mucus layer.

Amoebic Colitis

In some cases, the infection leads to the swelling of the colon or large intestines. Patients experience diarrhea (loose and sometimes bloody) along with pain in the abdomen.

Rarely the infection develops into fulminant amoebic colitis. This is more severe and dangerous, with high mortality. Severe stomach pain, bloody diarrhea, and fever occur at the same time.

Cutaneous amoebiasis

This is a rare complication that affects the skin of the patient. Ulcers, or skin lesions, in the perineal area are painful and have foul smells.

For adults, this is usually a result of anal intercourse. For babies, this may happen as a result of wearing diapers.


This happens when parasites reach other organs of the body by travelling thru the bloodstream.

Amoebic Liver Abscess

The liver is the organ most commonly affected when Entamoeba hystolitica exits the colon. The parasites damage the liver and abscess (collection of pus) eventually develops.

It is uncommon but also possible for parasites to spread to the brain, lungs, or any other organ. In all cases, the results could be fatal if left untreated.

Clinical Diagnosis

In order to find out if a person has amoebiasis, the doctor may order a series of tests.

Stool Analysis

This is the first step in detecting the presence of Entamoeba hystolytica. The parasites (in both stages – trophozoite and cyst) may not always be present in stools. So the laboratory might ask for stool samples over the course of a few days.

Other parasites (Entamoeba dispar) look the same as Entamoeba hystolytica under a microscope. This calls for a thorough and careful examination to ensure proper diagnosis and treatment.

Blood Test (Antibody detection)

A blood test may be required if the doctor suspects amoebiasis despite not finding Entamoeba hystolitica in stools. One limitation is that the presence of antibodies may be because there was an infection in the past.


To check for liver lesions, patients may need an ultrasound or CT scan.

Other methods of diagnosis include colonoscopy and Polymerase Chain Reaction (PCR) test.

Treatment and Medication

Do I need to see a doctor?

It is highly advisable to consult a doctor when there are signs of amoebiasis. If diarrhea becomes bloody or lasts for more than 3 days, go to the hospital immediately.

For mild cases, the doctor might prescribe oral or intravenous medication. It usually takes 7-10 days for the drugs to kill the parasites.

A stool exam or fecalysis will be performed before and after the treatment.
Currently, no vaccine is available to treat amoebiasis in humans.

How to treat complications?

Complications from amoebiasis are managed by killing the parasites in the body. Oral medications using two agents (tissue and luminal) cure intestinal complications.

Doctors will also prescribe a series of oral medications for extra-intestinal complications like an amoebic liver abscess. The size of the lesions will be considered in determining the type of treatment to be applied.

What if I am asymptomatic?

Keep in mind that amoebiasis is highly contagious. All carriers can spread the parasites. If you went to unsanitary places in your previous activities, it is advisable to consult a doctor and conduct tests.


Proper sanitation is key to stopping the spread of amoebiasis. Always wash your hands thoroughly before and after using the bathroom.

Do not drink water directly from the faucet in unfamiliar places. When travelling, make sure also that you only eat well-prepared food.

Lastly, educate the people about amoebiasis and its causes.

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