Lecture on Pathogenic Ameba and Intestinal Flagellates

Flashcards covering key concepts related to pathogenic amoebas and intestinal flagellates from the lecture notes.

What is the infective form of the only pathogenic ameba?

Mature quadrinucleate cyst

How is amebiasis transmitted?

Ingestion of food and water contaminated with the cysts

What are common symptoms of amebic colitis?

Abdominal cramping, anorexia, fatigue, and diarrhea

What shape characterizes the typical amoebic ulcer?

Flask-shaped in cross section

What complication can occur from a chronic amoebic ulcer?

Granulomatous pseudotumoral growth (amoebic granuloma or amoeboma)

What is the typical manifestation of intestinal amoebiasis?

Amoebic dysentery

What is the most common extraintestinal complication of amebiasis?

Hepatic involvement (liver abscess)

What does the abscess center contain in hepatic amebiasis?

Thick chocolate brown pus (anchovy sauce pus)

What symptoms occur with pulmonary amebiasis?

Expectoration of chocolate brown sputum

In which condition does CNS involvement lead to secondary amebic meningoencephalitis?

Amebiasis

What special media is used to support E. histolytica in culture?

TYI-S-33

What serologic test is diagnostic of amoebic hepatitis?

Indirect Hemagglutination Test (IHA) with titer of 1:256 or more

How do Entamoeba histolytica and Entamoeba coli differ in their motility?

E. histolytica moves unidirectionally; E. coli moves sluggishly in several directions.

What is a key feature of Entamoeba histolytica's trophozoite morphology?

Contains RBCs but no bacteria or cell detritus

What distinguishes Entamoeba coli cysts from those of E. histolytica?

E. coli cysts may contain 1-8 nuclei and have splinter-like chromatoidal bars.

What is characteristic of the karyosome in Endolimax nana?

Large, blot-like karyosome, usually centrally located with no peripheral chromatin.

What is the most prominent feature of Iodamoeba butschlii?

Large iodine-staining glycogen vacuole.

What is unique about Entamoeba gingivalis regarding its life cycle?

It has no cystic stage.

What are the defining features of Entamoeba dispar?

Morphologically identical to E. histolytica; requires specialized tests for speciation.

What is unique about Entamoeba moshkovskii's growth conditions?

It can grow at room temperature and survive at temperatures ranging from 0-41°C.

How is Entamoeba hartmanni characterized in comparison to E. histolytica?

It is smaller and does not ingest RBCs.

Which species primarily infects pigs and monkeys, and rarely humans?

Entamoeba polecki.

What infection is caused by Naegleria fowleri?

Primary Amoebic Meningoencephalitis (PAM)

How does Naegleria fowleri enter the body?

By inhalation or aspiration of water, dust, or aerosols containing trophozoites or cysts.

What is Acanthamoeba spp. primarily known for?

Causing Granulomatous Amebic Encephalitis (GAE) and keratitis.

What differentiates Acanthamoeba from Naegleria fowleri?

Acanthamoeba does not have a flagellated stage.

What is the method for culturing Acanthamoeba spp.?

Using non-nutrient agar plates with Page’s saline and E. coli overlay.

What shape is the cyst of Balamuthia mandrillaris characterized by?

Having three layers in the cyst wall.

What type of motility do Enteromonas hominis trophozoites exhibit?

Jerky motility.

What is the usual size range of Giardia lamblia cysts?

Median bodies: two in immature cyst or four in fully mature cyst.

How is giardiasis transmitted?

By ingestion of cysts in contaminated water and food or oral-anal contact.

What is the preferred diagnostic method for Giardia lamblia?

Stool Exam or Fecal antigen detection by EIA and ELISA.