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Amoebiasis, also known as amoebic dysentery, is a disease caused, like giardiasis or trichomoniasis, by a unicellular parasitic organism called colonic amoebiasis, which is usually located in the large intestine in humans.
Amoebiasis of the colon
The parasite that causes amoebiasis is relatively common in the tropics and subtropics. In Poland, it is estimated that it occurs in about 2% of the population, and usually among people returning from these regions or having contact with people who came from there. Therefore, patients with amoebiasis are usually recorded in port cities and among coastal residents.
Colonic amoebiasis usually feeds on:
- red blood cells,
- elements of other cells of the patient,
- bacteria,
- mushrooms.
It usually lives in the lumen of the intestine, in the intercellular spaces of the intestinal wall, but it can also get to other organs, causing, for example, liver abscesses that are dangerous for the body.
The causes and mechanism of the formation of amoebiasis
Humans are infected with amoebiasis by ingesting:
- fruit,
- other foodstuffs infected with cysts
- infected water.
They play a large role in spreading this infection flies, which have transferred cysts from unprotected sewage, lavatories, sewage pits and other places of pollution where we can find cystic forms of the dysentery amoeba.
The ingested cyst, which is resistant to the digestive effects of gastric juice, is then moved to the end of the small intestine or the beginning of the large intestine (where its shell dissolves). The released protozoa rapidly multiply and move to the large intestine as a small form of a parasite, which is practically harmless and non-pathogenic for humans, because it feeds mainly on bacteria and fungi abundant in the digestive tract.
Amoebiasis – symptoms
Small amoebiasis of the colon can stay and multiply in the human body for many years without showing any disease symptoms. At this time, a person is a dangerous carrier of this form of the parasite, because from time to time some of the small forms transform into cysts and are excreted with the faeces.
In patients with a weakened organism, the small forms may turn into the large form, which is a dangerous parasite of pathogenic humans. Then an acute or chronic intestinal form of amoebiasis appears, called amoebic dysentery.
In such a situation, pathogenic parasites:
- penetrate the epithelium of the intestinal mucosa as well as the sub-epithelial and intramuscular spaces,
- absorb red blood cells,
- damage the walls of capillaries,
- promote the formation of ulcers and more or less profuse bleeding from the gastrointestinal tract,
Hence the name of amoebic dysentery. At the same time, the parasites create a favorable environment for bacterial infection, which contributes to the formation of abscesses.
Amoebiasis can also get through the portal circulation to the liver through various routes of infection, and even further through the inferior vena cava, right atrium, and right ventricle to the lungs, thereby causing abscesses of the liver or lungs.
Depending on the location of the parasites in symptomatic amoebiasis, the following forms are distinguished:
- intestinal,
- enterohepatic,
- enterohepato-pulmonary.
In patients with amoebiasis, disease symptoms are related to the location of parasites, the intensity of infection and secondary infections.
Clinical symptoms
Local parasitic lesions are accompanied by clinical symptoms such as:
- pain ailments,
- flatulence
- cough,
- purulent sputum,
- strong weakness,
- anemia,
- nausea,
- headaches,
- abdominal pain,
- perianal fistulas,
- stool pressure (frequent and painful),
- dehydration,
- soreness and enlargement of the liver,
- low-grade or feverish states,
- chills,
- an allergic reaction such as a rash.
Diagnosis of amoebiasis
The diagnosis of amoebiasis is based on the detection of live or dead parasites in fresh stool samples or cysts in the intestinal mucosa samples taken during the rectoscopythanks to which it is possible to show the presence of amoebiasis or to identify ulcers. Patients diagnosed with amoebiasis should be isolated from the environment.
Amoebiasis – treatment
Treatment of amoebiasis should be carried out only under the supervision of a doctor, because antiparasitic preparations are quite poisonous drugs. If untreated, the disease can even kill the patient due to toxic damage to the circulatory system (and other organs), as well as from multiple chronic intra-organ abscesses, major haemorrhages, or dehydration.
Can amoebiasis be prevented?
Prophylaxis in amoebiasis consists in:
- taking care of personal hygiene,
- taking care of the proper sanitary condition of water,
- the proper protection of foodstuffs (both during production, transport and consumption) so that parasite-carrying insects or their cysts do not have access to them.