PROTOZOANS - AMOEBA

True

True or False.

Protozoans are unicellular, eukaryotic organisms.

False

True or False.

Protozoans are multicellular, eukaryotic organisms.

Karyosome and peripheral chromatin

The nucleus of protozoans contain?

Cytostome

It is used as the mouth of the parasite because they have no digestive system.

Binary fission

Another term used for asexual reproduction in protozoans.

Trophozoite

What parasite stage require a wet environment for feeding, locomotion, osmoregulation, and reproduction?

Pseudopodia (false feet)

Amoebas

What is the locomatory organelle of sarcodina?

State an example.

Flagellate

Leishamnia, Trypanosoma, Giardia, Trichomonas

What is the locomatory organelle of mastigophora?

State an example.

Cilia

Balantidium coli

What is the locomatory organelle of ciliophora (infusoria)?

State an example.

None, because they are obligate intracellular parasites.

Plasmodium, Cryptosporidium, Toxoplasma, Babesia, Isospora

What is the locomatory organelle of sporozoans?

State an example.

Cyst stage and Trophozoite stage

The life cycle of amoebas.

E. histolytica

All amoebas are commensal except?

E. gingivalis

All amoebas inhabit the intestine except?

E. gingivalis

All amoebas have cyst stage except?

Entamoeba genus (true amoeba)

These are the type of amoebas with peripheral chromatin and chromatoidal bodies.

• Endolimax nana

• Iodamoeba bustchlii

These are the type of amoebas with no peripheral chromatin and chromatoidal bodies.

Cyst

This is the form of the parasite that is considered as the non-feeding stage (non-motile).

Trophozoites

The form of parasite that feeds, multiplies, and possesses pseudopods (Motile).

Cyst stage

This form of parasite is characterized by a thick protective cell wall designed to protect the parasite from the harsh outside environment

Trophozoite stage

This form of parasite is characteristically delicate and fragile because of their ability to produce and use pseudopods (vegetative state).

Cyst stage

This form is commonly seen as the infective and diagnostic stage.

Trophozoite stage

This form is commonly seen as the diagnostic stage.

Trophozoite stage

This stage cannot be studied with iodine stain because it is destroyed, as well as by concentration techniques.

Excystation

The process that the parasite undergoes when the environment is deemed favorable (ex. wet, moist, and packed with nutrients).

Encystation

The process that the parasite undergoes when the environment is deemed unfavorable (ex. dry) to prolong its life cycle.

• Karyosome

• Peripheral chromatin

• Cytoplasmic inclusions

• Motility

In laboratory diagnosis, what are the 4 morphologic determination of parasites?

Entamoeba histolytica

Only amoebic pathogen that causes a significant disease.

• Lecithin

• Amoebopores

• Cysteine proteinases

What are the virulence factors of E. histolytica?

Cysteine proteinases

What virulence factor of E. histolytica causes characteristic flask-shaped ulcers?

E. histolytica trophozoite

This parasite has a bull’s eye central karyosome, fine and evenly distributed peripheral chromatin, and ingested RBCs in the cytoplasm. It has fingerlike pseudopodia.

E. histolytica cyst

This parasite is spherical and round, has 1-4 nuclei (quadrinated) and a central karyosome. The peripheral chromatin is fine and evenly distributed, with cigar or sausage shaped chromatoid bars and diffuse glycogen mass.

Chromatoidal bars

A cytoplasmic inclusion that is used for the storage of food or nutrients during cyst stage.

• Stool

• Sigmoidoscopy material

• Hepatic abscess

The specimens for E. histolytica

TYI-S-33

The culture used for E. histolytica

Molecular analysis or Serological methods

This is used to distinguish E. histolytica from E. dispar and E. moshkovskii since they are morphologically identical.

• Cyst and trophozoite

• Cyst

E. histolytica

• Diagnostic stage

• Infective stage

Ingestion of cyst

Mode of transmission of E. histolytica

Flies and cockroaches

These are the mechanical vectors of E. histolytica

• Amoebic colitis

• Amoebic dysentery (flask shaped ulcers)

• Extraintestinal amoebiasis

• Venereal amoebiasis (Gay bowel syndrome)

State clinical symptoms of E. histolytica

Metronidazole

Treatment for Entamoeba histolytica

E. dispar and E. moshkovskii

These are morphologically similar to E. histolytica, but there are no ingested RBCs. The DNA and RNA are different.

Entamoeba hartmanii

Considered as small race histolytica.

Entamoeba coli

This is considered as dirty entamoeba and more common commensal amoeba.

E. coli trophozoite

This parasite is huge, hence its non-progressive and sluggish motility. It has a large, eccentric karyosome, with unevenly distributed peripheral chromatin and blunt pseudopodia.

E. coli trophozoite

This parasite has cytoplasmic inclusion such as vacuoles, bacteria, yeast, and cell debris.

E. coli cyst

This parasite has 1-8 nuclei, unevenly distributed, thin chromatoidal bars with pointed ends (whisk broom appearance/ splintered needles), and diffuse glycogen mass.

E. poleckii/ chattoni

This parasite is uninucleated, small central karyosome, and has inclusion mass, angular chromatoid bars with pointed ends, and evenly distributed peripheral chromatin.

Endolimax nana

This parasite has spherical, ellipsoid shape, 1-4 nuclei, large blotlike central karyosome, no peripheral chromatin, and chromatin granules.

Iodamoeba butschlii

This parasite is ovoid or ellipsoid, uninucleated with basket of flowers shape, no peripheral chromatin, and has a large iodine vacuole and chromatoid bar.

Iodamoeba butschlii

This amoeba easily stains with iodine.

E. gingivalis

The only amoeba with no cystic stage.

E. gingivalis

Gum line/ Mouth

The only extraintestinal amoeba.

Where is it found?

Mouth scrapings

The specimen for the recovery of E. gingivalis

• Mouth to mouth contact

• Droplet contamination

How is E. gingivalis transmitted?

E. gingivalis

This parasite has active motility, fine and evenly distributed peripheral chromatin, and ingested WBCs and epithelial cells.

Naegleria fowleri

This parasite is also known as brain-eating amoeba.

Naegleria fowleri

This parasite is seen in warm bodies of water, including lakes, streams, ponds, and swimming pools.

Naegleria fowleri

This parasite bridges amoebas and flagellates.

Legionella pneumophila

Legionnaire’s disease

The parasite of a parasite, usually seen in Naegleria fowleri. What disease does it cause?

• Cyst

• Trophozoite

• Amoeboflagellate

What are the 3 morphological forms of Naegleria fowleri?

Primary Amoebic Meningoencephalitis

What disease does Naegleria fowleri cause?

PAM

This disease causes rapid tissue CNS destruction and infects even healthy individuals.

• Kernig’s sign

• Brudzinki’s sign

Signs and symptoms of PAM caused by Naegleria fowleri.

Trophozoite and Flagellate

(No cyst because it sinks in water)

The diagnostic and infective stage of Naegleria fowleri

Amphotericin B with rifampin and miconazole

Treatment for Naegleria fowleri

Acanthamoeba spp.

This parasite has spine-like pseudopodia and is an ubiquitous parasite.

Acanthamoeba spp. trophozoite

This parasite has sluggish motility, large eccentric karyosome, no peripheral chromatin, and spinelike pseudopods that appear as hyaline projections.

Acanthamoeba spp. cyst

This parasite has no peripheral chromatin, wrinkled double cell wall with ragged edges.

Granular Amoebic Encephalitis (GAE)

The primary disease of Acanthamoeba spp.

GAE

This disease causes gradual destruction of CNS and only infects immunocompromised patients. It does not directly infect CNS, only the surrounding organs and fluids.

Balamuthia mandrillaris

What other organism can cause GAE?

Amoebic keratitis

What is the secondary disease of Acanthamoeba spp.?

Amoebic keratitis

This disease is caused by contact lens solutions contaminated with Acanthamoeba spp. and can lead to severe eye inflammation and vision loss.

Acanthamoeba castellani

This parasite is the most commonly isolates species on most eye and CNS infection, such as Amoebic keratitis.

• CSF

• Brain tissue

• Corneal scrapings

The specimens for Acanthamoeba spp.

BAP with E.coli strain

This is the culture used for Acanthamoeba spp. where it produces a trailing effect as it feeds on bacteria.

Calcofluor white

What reagent is used for corneal scraping for staining cyst?

Diagnostic stage: Trophozoite and Cyst

Infective stage: Trophozoite

The diagnostic and infective stage of Acanthamoeba spp.

• Inhalation

• Contaminated contact lens solution

• Broken skin

MOT of Acanthamoeba spp.