Amoebiasis
Amoebiasis, or amoebic dysentery, is an infection of the intestines caused by a parasitic amoeba Entamoeba histolytica.[3][4] Amoebiasis can be present with no, mild, or severe symptoms.[2] Symptoms may include lethargy, loss of weight, colonic ulcerations, abdominal pain, diarrhea, or bloody diarrhea.[5][2] Complications can include inflammation and ulceration of the colon with tissue death or perforation, which may result in peritonitis.[2] Anemia may develop due to prolonged gastric bleeding.[2]
| Amoebiasis | |
|---|---|
| Other names | Amoebic dysentery, amebiasis, entamoebiasis[1] |
 | |
| The life-cycle of various intestinal Entamoeba species | |
| Specialty | Infectious disease |
| Symptoms | Bloody diarrhea, abdominal pain[2] |
| Complications | Severe colitis, colonic perforation, anemia[2] |
| Causes | Entamoeba histolytica [2] |
| Diagnostic method | Stool examination, antibodies in the blood[2] |
| Differential diagnosis | Bacterial colitis[2] |
| Prevention | Improved sanitation[2] |
| Treatment | Tissue disease: metronidazole, tinidazole, nitazoxanide, dehydroemetine, chloroquine, Intestinal infection: diloxanide furoate, iodoquinoline[2] |
| Frequency | ~480 million[2] |
Cysts of Entamoeba can survive for up to a month in soil or for up to 45 minutes under fingernails.[2] Invasion of the intestinal lining results in bloody diarrhea.[2] If the parasite reaches the bloodstream it can spread through the body, most frequently ending up in the liver where it can cause amoebic liver abscesses.[2] Liver abscesses can occur without previous diarrhea.[2] Diagnosis is typically made by stool examination using microscopy, but it can be difficult to distinguish E. hystolitica from other harmless entamoeba species.[3] An increased white blood cell count may be present in severe cases.[2] The most accurate test is finding specific antibodies in the blood, but it may remain positive following treatment.[2] Bacterial colitis can result in similar symptoms.[2]
Prevention of amoebiasis is by improved sanitation, including separating food and water from faeces.[2] There is no vaccine.[2] There are two treatment options depending on the location of the infection.[2] Amoebiasis in tissues is treated with either metronidazole, tinidazole, nitazoxanide, dehydroemetine or chloroquine, while luminal infection is treated with diloxanide furoate or iodoquinoline.[2] Effective treatment against all stages of the disease may require a combination of medications.[2] Infections without symptoms may be treated with just one antibiotic, and infections with symptoms are treated with two antibiotics.[3]
Amoebiasis is present all over the world,[6] though most cases occur in the developing world.[7] About 480 million people are currently infected with about 40 million new cases per year with significant symptoms.[2][8] This results in the death of between 40,000–100,000 people a year.[4] The first case of amoebiasis was documented in 1875 and in 1891 the disease was described in detail, resulting in the terms amoebic dysentery and amoebic liver abscess.[2] Further evidence from the Philippines in 1913 found that upon swallowing cysts of E. histolytica volunteers developed the disease.[2]