AMOEBIASIS Flashcards
What is the causative organism?
Amoebiasis is protozoan infection caused by Entamoeba Histolytica
Discuss ameobiases being symptomatic/asymbiomatic
It is asymptomatic in most cases(90%)
Produces spectrums of clinical syndromes in about 10% of cases
The symptomatic types can be intestinal or extraintestinal
Epidemology
It has global distribution and is the third most common cause of parasitic death worldwide accounting for about 100000 deaths annually.
Seen in Africa, India, Mexico
It is transmitted feco-orally
it is often endemic in regions of the world with limited modernsanitationsystems, including México, Central America, westernSouth America,South Asia, and western and southernAfrica
What are the three main events by which E. histolyticacauses tissue damage?
E. histolyticacauses tissue damage by three main events:
direct host cell killing, inflammation, and parasite invasion.
What are the molecules involved in pathogenesis of amoebiasis
The pathogenesis of amoebiasis involves interplay of various molecules secreted by E. histolytica such as LPPG, lectins, cysteine proteases, and amoebapores.
What are the functions of these molecules?
Lectins help in the attachment of the parasite to the mucosal layer of the host during invasion.
The amoebapores destroy the ingested bacteria present in the colonic environment.
Cysteine proteases lyse the host tissues.
Other molecules such as PATMK, myosins, G proteins, C2PK, CaBP3, and EhAK1 play an important role in the process of phagocytosis
Life Cycle
- Cysts and trophozites passed in formed stool
- ingestion of mature cysts from fecally contaminated food, water, or hands.
- Excystation (cysts transform into trophozoites) occurs in the small intestine and trophozoites are released, which migrate to the large intestine
- Trophozites multiply in the small intestine by binary fission to produce cysts and both stages are passed in the feces
Clinical Symptoms of Ameobiasis
Bloody diarrhea
Right flank pain
Low grade fever
Abdominal swelling
Weight loss
Diagnosis
Flask shaped ulcer with undermined edges in the colon
Antibody detection tests
Stool microscopy
PCR or qPCR of stool or liver abscess pus for E histolytica DNA
Stool antigen detection
Chest X-ray
Liver Ultrasound
CT Skull
Complications
Liver abscess
Splenic abscess
Lung abscess
Pericolic and Pericaecal abscesses
Amoeboma
Brain abscess
Cutaneous amoebiasis
Treatment
an amoebicidal tissue-active agent and a luminal cysticidal agent e.g Metronidazole (flagyl) and Diloxanide (For people who are symptomatic, it is used after treatment with metronidazole)
