U2 - Amoebae Flashcards
Phylum Sarcodina species
Pathogenic: Entamoeba histolytica
Commensals:
1. E. dispar
2. E. moshkovskii
3. E. hartmanni
4. E. coli
5. Endolimax nana
6. Iodamoeba butschlii
Identify the amoeba:
Most invasive of the Entamoeba parasites
Entamoeba histolytica
Identify the amoeba:
Only member to cause colitis and liver abscess
Entamoeba histolytica
Entamoeba histolytica:
Mechanisms for virulence
- production of enzymes or other cytotoxic substances
- contact-dependent cell killing
- cytophagocytosis
Entamoeba histolytica:
Cases may manifest as?
- Asymptomatic
- Amebic Colitis
- Ameboma
- Amebic Liver Abscess
Identify the condition:
abdominal pain + diarrhea +/-
blood & mucus in the stools
Amebic Colitis
Identify the condition:
Children may develop fulminant colitis (severe bloody diarrhea + fever + ab pain)
Amebic Colitis
Identify the condition:
A mass-like lesion with abdominal pain and a history of dysentery
Ameboma
Identify the condition:
Can be mistaken as a carcinoma
Ameboma
T/F:
Ameboma is always symptomatic.
False;
May be asymptomatic
Identify the condition:
most common extra-intestinal form of amebiasis
Amebic Liver Abscess
Identify the condition:
Usually presents with fever and right upper quadrant pain
Amebic Liver Abscess
Entamoeba histolytica:
diagnosis
- DFS
- Concentration techniques (FECT)
- PCR
- Serological tests (ELISA): for ALA
- Ultrasound, CT scan, MRI
Entamoeba histolytica:
treatment
- Metronidazole
- Diloxanide furoate
Entamoeba histolytica:
epidemiology
- Amebiasis: 1-5% worldwide
- 3rd most important parasite
(malaria, schistosomiasis)
Entamoeba histolytica:
prevention and control
- Proper sanitation
- Safe water supply
- Good personal hygiene
- Proper food preparation
- Vaccines
Identify the amoeba:
Non-pathogenic and morphologically similar to E. histolytica
E. dispar
E. moshkovskii
Identify the amoeba:
Ameba of swine (pigs)
Iodamoeba butschlii
Iodamoeba butschlii:
prominent features
- Uninucleated with a large eccentric karyosome; with achromatic granules “Basket of Flowers”
- Large Glycogen Vacuole
Identify the Free Living Pathogenic Amebae:
Found Inhabiting Lakes, Pools, Tap Water, Air Conditioning Units and Heating Units
- Acanthamoeba
- Balamuthia
- Naegleria
Naegleria fowleri:
Important Stages
- Cyst
- Trophozoite
Naegleria fowleri:
Entry into the body
- Olfactory Epithelium
- Respiratory Tract
- Skin
- Sinuses
Naegleria fowleri:
Disease Manifestation and Pathology
Primary Amebic Meningoencephalitis
Naegleria fowleri:
Diagnosis
- Wet Mount Examination of CSF
- Smears stained with Wright’s or Giemsa
- Biopsy
- CSF Analysis
- Culture
- Molecular Methods
Naegleria fowleri:
Treatment and Prevention
Amphotericin B with Clotrimazole
Acanthamoeba spp.:
Morphologic Forms
- Cyst
- Trophozoite
Acanthamoeba:
Disease Manifestation and Pathogenesis
- Granulomatous Amebic Encephalitis
- Amebic Keratitis
Acanthamoeba:
Diagnosis
- Usually diagnosed after death (GAE)
- Biopsy
- Corneal Scrapings
- Culture
- Molecular Methods
Acanthamoeba:
treatment
- Very fatal once cerebral manifestations appear
- Fluorocystine, ketoconazole, amphotericin B
