Symptoms of amoeba carriers | Amoebas

Symptoms of amoeba carriers

Depending on the type of amoebic dysentery, the affected individuals may experience more or less severe symptoms. While amoeba carriers with a pure intestinal lumen infection in most cases do not develop any symptoms, other patients typically suffer from severe, watery diarrhoea. The symptomless intestinal lumen variant occurs in about 80 to 90 percent of all amoeba infections.

Variants of amoebic dysentery that lead to severe diarrhoea, however, are comparatively rare among all amoebic infections. In the case of invasive intestinal amoebic dysentery, amoebae can also be detected in the intestinal tissue. For this reason, the affected patients show pronounced symptoms.

Typically, the majority of those affected develop bloody-mucilaginous, raspberry jelly-like diarrhoea at an early stage. In addition, cramp-like abdominal pain and pain during bowel movements are among the most common symptoms of this variant of amoebic dysentery. Due to the amoeba infestation of the intestinal tissue, nutrients can only be insufficiently absorbed.

A large part of the energy sources necessary for normal organ processes is excreted unused with the diarrhoea. Therefore, patients suffering from intestinal amoebic dysentery usually lose weight quite quickly. About 30 to 40 percent of patients with intestinal amoebic dysentery and severe diarrhoea also suffer from high fever.

One speaks of extraintestinal amoebic dysentery when the causative amoebae not only infect the intestinal tissue but can also be detected in other organs. In most cases, the causative amoebae spread from the intestinal tissue to the liver, brain and/or spleen. In this context, however, the amoeba infection of the liver is the most common variant.

People with extraintestinal amoebic dysentery do not necessarily suffer from diarrhoea. However, the occurrence of diarrhoea does not rule out an extraintestinal infection. If the liver tissue is affected, a fist-sized, usually single abscess (so-called amoebic liver abscess) forms. This is a cavity in the liver tissue filled with purulent secretion. The presence of such an amoebic liver abscess is usually indicated by the following symptoms:

  • High fever
  • Cough
  • Sensitivity to pressure or pain in the right upper abdomen
  • Enlargement of the liver
  • General symptoms (e.g. tiredness, weakness, exhaustion)


During the amoeba infection, the amoeba cysts excreted with the stool are transmitted. An infection occurs mainly when little or no importance is attached to hygiene. Amoeba cysts can be transmitted both through contaminated food and through contaminated drinking water.

A direct infection via the mouth cannot be ruled out either, provided that there is appropriate contact. Immediately after the actual infection, trophozoites develop again in the human body from the amoeba cysts. These can then settle in the intestine and/or in other organs and lead to amoebic dysentery.

It must also be noted that an amoeba infection does not necessarily lead to disease in every person. So-called “symptomless carriers” do not show any symptoms, but can pass on the causative unicellular organisms. The most important amoeba affecting humans, Entamoeba histolytica, reproduces in the human intestine and does not usually affect animals.

In an active infection, the host excretes many millions of infectious cysts with the stool, which, if ingested orally, can trigger a new infection. The pathogen is therefore dependent on faecal-oral transmission and is therefore mainly spread in areas with poor wastewater infrastructure and drinking water hygiene. When travelling to the tropics, certain precautions should be taken.

If in doubt, boil tap water and do not eat unwashed fruit. Not every infection also leads to a spread of the pathogens in the intestines. In some cases, the pathogens survive in the intestines for several weeks without causing symptoms and then die off again. It can also lead to a permanent infestation, which may take months or years to develop into a disease. In such unclear cases it is particularly important to inform the treating physician about previous trips to tropical regions.