Entamoeba Histolytica The Beast of the Bowels

Profile of the Pathogen Entamoeba Histolytica is a unicellular amoeba that infects humans and lives in the lower bowels. It’s name means bowel destroying amoeba. It infects an estimated 50 million people worldwide It is the third leading cause of parasitic death, surpassed only by schistosomiasis and malaria.

Microorganism of Malice The 4 stages of Entamoeba Histolytica’s life are the trophozoite form, the precyst form, the cyst form and the metacyst form.

Protist of Perniciousness Measures between 15 and 50 micrometers. Reproduces primarily by binary fission Has hyaline ectoplasm and distinct karyosome in a nucleus. Adheres to intestinal wall via lectin an adherence lectin Consumes erythrocytes and other somatic cells Is capable of lysing leukocytes and evading complement-mediated lysis

The Cyst of Corruption In the precyst form, the cell shrinks as it extrudes food vacuoles The cyst forms 4 distinct nuclei, measures between 10 and 20 micrometers, and has no visible chromatoid bodies. The metacyst is a tetranucleated amoebae without a shell around it.

The Circle of Calamity The cyst forms in the bowels, and from there is passed out to the environment inside fecal matter. From the environment, the cysts are ingested by another human host.

Suffering Spreads Entamoeba Histolytica is transmitted by the fecal-oral route. Incidence of Entamoeba Histolytica is high in developing countries with poor sewage. The only population that shows increased incidence of Entamoeba Histolytica infection in the industrialized world is that of homosexual men.

The Reaping Infection with Entamoeba Histolytica is known as amebiasis There are 2 forms of amebiasis, invasive and non-invasive

The Battlefield

The Lurking Darkness Non-invasive amebiasis accounts for 90% of Entamoeba Histolytica infections The symptoms include slight stomach pain and infrequent non-dysenteric diarrhea

Eviscerator of Viscera Entamoeba Histolytica trophozoites penetrate the mucosa and begin to feed on the epithelial intestinal surface This feeding causes characteristic flask-shaped ulcers of necrotic tissue in the intestines Small ulcers grow and meet with other ulcers to cause sloughing of the intestinal wall Sometimes the intestinal skin around the ulcer thickens, creating an ameboma

Torment of the Transgressor The primary symptom is dysentery, with affected individuals sometimes suffering upwards of 20 bowel movements a day Stool is soft, and may contain blood, mucus or pieces of intestinal epithelium In some cases gangrene sets in within the intestines, or the intestines will rupture causing peritonitis

The Abomination of the Abdominal Cavity Occasionally Entamoeba Histolytica will spread to other organs. The most common one is the liver, which it reaches through the hepatic portal vein. In the liver it causes abscesses, hepatomegaly and cirhosis. Even more rarely, Entamoeba Histolytica may spread to other parts of the body such as the lungs or brain.

Bring out your dead… Mortality rate in patients with uncomplicated amebic liver abscess is less than 1% Fulminant amebic colitis has a mortality rate of more than 50% Pleuropulmonary amebiasis has a mortality rate of 15-20% 
 Amebic pericarditis has a case fatality rate of 40% Cerebral amebiasis is highly fatal, with a 90% death rate