To change, because Amoebas have definite and variable shapes.
Amoeba belongs to what phylum?
Sarcodina.These organisms have streaming cytoplasm and use temporary cytoplasmic extensions called pseudopodia in locomotion (called amoeboid movement) and feeding.
Amoeba is of several tiny, one-celled protozoa. True or False?
True.
The only specie of the different intestinal amoebae which has the potential for tissue invasion.(Tissue lysis)
.
Entamoeba histolytica
________ (1903) established the differentiation between Entamoeba histolytica and Endamoeba coli, he decided to call it E. histolytica because of its ability to cause tissue lysis.
Name that scientist.
Fritz Schaundinn
True or false. Amoebiasis is more prevalent in the tropics & subtropics & in unsanitary places regardless of climate.
True
True or false? Ingestion of one viable cyst can already cause an infection.
True
Does e. histolytica ingest blood?
Yes.They feed up on erythrocytes, mucosa and submucosa of colon.
How can one acquire e.histolytica infection?
☢ Through eating raw vegetable.
☢ Drinking contaminated water
☢ Flies and food handlers (vector of cyst)
☢ Faeco- oral (caused by infectious agents whose route of exit from the body is in the faeces, and whose route of entry to new hosts is via the mouth)
☢ sexual contact
☢ use of night soil as a fertilizer in the vegetable farms
E. histolytica move by means of _______ or also known as _______.
pseudopodia/pseudopodium or "false feet"
Diverse mammals (dogs & cats) can become infected and may produce cysts with their feces, thus contributing significantly to transmission. True or false?
False. Diverse mammals can be infected however they do not shed cyst thus is not a top contributor for transmission. Unlike person-to-person transmission through different routes such as faeco-oral.
Amoebas in general change shape constantly. Thus they are ______.
Amorphous
Arrange the life cycle of entamoeba histolytica in correct order.
A. Flies carries cyst that is excreted in the feces.
B. Migrates to the caecum ang sigmoido-rectal area in the small intestine.
C. Cyst is swallowed by human.
D. Cyst is excreted through stool.
C-B-D-A and the cycle goes on.
What is the infective stage of e.histolytica?
Cyst, rather than trophozoite. Trophozoites can also be passed in diarrheal stools,but are rapidly destroyed once outside the body, and if ingested would not survive exposure to the gastric environment. Cyst are non-reactive to the environment thus it is not affected by any environmental factors. It survives more than trophozoites.
Trophozoites can cause amoebic dysentery. True or false?
True.
Amoebic dysentery is a condition in which the infection is confined to the intestinal canal and is characterized by the passage of of blood and mucus in the stool accompanied by tenesmus.
Tenesmus- a feeling of incomplete defecation. It is experienced as an inability or difficulty to empty the bowel at defecation.
In having amoebic diarrhea, those with asymptomatic cases with
tendency to mimic other GIT conditions like appendicitis, gastritis,
peptic ulcer & others. True or false?
True.
Pathogenesis of amebiasis.
What are the non-invasive effect of amebiasis?
1.ameba colonizes the intestinal mucosa.
2.cyst are passed by asymptomatic host.
3.patient may experience diarrhea, abdominal cramps or other gastrointestinal symptoms.
Pathogenesis of amebiasis.
What are the invasive effect of amebiasis?
1. necrosis of the mucosa which causes ulcers and dysentery.
2. ulcer enlargement which may cause dysentery and peritonitis
3.metastasis in the extraintestinal amebiasis.
*metastasis- spread to other sites of the body*
What are the areas that could be affected by amoebiasis?
Intestinal disease
1.Intestine - trophozoites invade the intestinal mucosa.
Extra intestinal disease
2.Liver (liver abscess)
3.Brain
4.Lungs
5.Spleen
Disease caused by amoeba.
Flasked shape ulcer with narrow neck due to lytic action of trophozoites and broas necrotic bed seen.
Amoebic colitis.
Disease caused by amoeba.
Inflammatory thickening of the wall of large bowel resembling carcinoma colon.
Ameboma. - is non-fibrotic and contains granulation tissue with lymphocytes, plasma cells, eosinophils and giant cells.
It occurs commonly in caecum and rectosigmoid junction.
How does e.histolytica show its invasive effect?
☆Trophozoites or their progenies reach the cecum (in the large intestine— if intestinal infection. In different areas such as the brain, the liver, spleen, or lungs — if extraintestinal infection)
those that come in contact with the cecal mucosa penetrate or invade the epithelium by lytic digestion if conditions are right.
☆Trophozoites burrow with tendency to spread laterally by continuous lysis of cells until they reach the submucosa forming flask-shaped ulcers.
Metastatic lesion could reach what areas in the in the body?
1. In the brain where it could cause cerebral amoebiasis.A single small lesion in the cerebral hemisphere could develop.
2.Cutaneous amoebiasis, in areas of drainage of the liver abscess or colostomy wound.
3.Splenic amoebiasis
4.Amoebiasis of the penis which could be due to homosexual sexual contact.
5.Amebic pericarditis, caused by a rupture of a left-liver lobe abscess
6. Caridac tamponade, a serious medical condition in which blood or fluid fill the space between the sac that encases the heart and the heart muscles.
Involves extension of lesions in the skin of the abdominal cavity and that of the perineal area.
.