Amoebae

Question 1

What are the 3 main species of pathogenic amoebae

Answer 1

Entamoeba histolytica

Entamoeba gingivalis

Many Naegleria species

Question 2

General characteristics of amoebae

Answer 2

They move by cytoplasmic flow**, forming and retracting **pseudopodia

Can form cysts in harsh conditions.

The Cyst is the infectious stage

The Trophozoite is the actively feeding/growing stage.

Question 3

E. histolytica transmission

Answer 3

Found in tropical regions,

fecal-oral transmission from contaminated water, or contaminated crops that used human fecal fertilizer

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cysts are activated by stomach acid to mature

Question 4

E. histolytica clinical presentation

treatment

Answer 4

1. Intestinal Amebiasis:
   
   • cytotoxins kill GI cells, causing flask shaped ulcers
   • bloody diarrhea
   • cytotoxin and galactose inhibitable adherence proteins mediate attachment and damage
2. Extra-intestinal amebiasis
   
   • Fever, systemic inflammation/infection signs, leukocytosis, CRP etc
   • Right lobe of liver is most common infection site, usually a single cyst is formed, but may be multiple.
   • “Achovy paste” filled abscesses.
   • Hepatosplenomegaly with painful right upper quadrant
3. Treatment:
   
   • metronidazole for extra intestinal
   • paramycin and iodoquinol for intestinal/luminal

Question 5

Entamoeba gingivalis clinical presentation

Answer 5

Asymptomatic oral flora

or

Gingivitis and periodontitis

Question 6

Entamoeba Coli clinical presentation

Answer 6

A non-pathogenic GI colonizer/resident that is related to histolytica but doesn’t cause symptoms.