Amoebic Dysentery

What is it?

Amoebic dysentery is diarrhoea caused by a type of parasite called an amoeba. People usually get it by eating contaminated food or drinking contaminated water.

Life-cycle of the Entamoeba histolytica

Who may be affected?

Amoebic dysentery is more common in countries where people don’t have clean running water or may have difficulty keeping kitchens and toilets clean.  Amoebic dysentery can also be passed from person to person, usually when contact is made with the faeces of an infected person during handshakes, and the contaminated hand is used to feed. Sometimes, the parasites are in the bowel without causing any symptoms, and the individual passes it on to other people.

Amoebic dysentery may also be got if you live in crowded places, have a weak immune system (because you have HIV or are receiving chemotherapy), or through oral or anal sex.

What are the symptoms?

The main symptom is frequent passage of loose or watery stools which may contain blood or mucus later. There could also be:

  • bleeding from the rectum
  • abdominal pain
  • pain when going to the toilet to pass stools
  • high fever
  • headache
  • nausea
  • loss of appetite
  • Diarrhoea can make you lose too much water (dehydration), but you can prevent this by taking enough water.

What treatments work?

When your doctor has confirmed the presence of amoebic dysentery by performing some tests on your stool and blood, they will prescribe some drugs for you.

Metronidazole or Tinidazole  may be given for about 5 days. After treatment of the invasive disease, the bowel should be cleared of parasites with a drug such as diloxanide furoate which is effective in killing parasites in the gut. This may be taken for about 10 days, and it helps prevent you from transmitting the infection to others.

These medicines for amoebic dysentery can have side effects in some people, but they

are usually mild. They include:

• nausea and vomiting

• pain in your abdomen, and diarrhoea

• a bitter metallic taste in your mouth or a tongue that looks coated (furry)

• weakness or dizziness

• dark-coloured urine

• pain while urinating

• loss of appetite

• rash

• trouble sleeping

• blurred vision or headaches.

What will happen to me?

If the infection is not treated early, complications may occur. These include involvement of the liver, which can cause swelling in your abdomen.

Sometimes the amoebas can cause a more serious condition called fulminant colitis, in which your bowel is severely swollen and your abdomen painful all over. It is however rare but can be life threatening.

It’s important that you see a doctor as soon as possible if you get any of these symptoms.


Amoebiasis is difficult to eradicate because of the substantial human reservoir of infection. The only progress will be through improved standards of hygiene, sanitation and better access to clean water. The parasites are destroyed by boiling, but chlorine and iodine sterilizing tablets are not always effective.