Protozoans - Amoebe, Flagellates, Ciliates

What is the only ciliate known to infect humans?

Neobalantidium coli

What are the three flagellates known to infect humans?

1. Giardia lamblia

2. Chilomastix mesnili

3. Dientamoeba fragilis

What are the six amoebae that infect humans?

1. Entamoeba hystolytica

2. Entamoeba hartmanni

3. Entamoeba coli

4. Entamoeba polecki

5. Endolimax nana

6. Iodamoeba butschlii

What is the infective form of the amoebas?

Cyst stage

What is the infective form of Dientamoeba fragilis? Why is this the case?

1. Trophozoite

2. Because there is no known cyst stage

What is the infective form of flagellates and ciliates?

Cyst stage (with exception of Dientamoeba fragilis)

Why are trophozoites not present in wet preps?

Because they are destroyed by both formalin and concentration procedures

What stain is used to preserve trophozoites? What group is the exception?

1. PVA-fixed material

2. Flagellates and ciliates (that don’t respond to PVA or formalin)

What is the most common parasitic infection in the world?

Giardia lamblia

Why is giardia lamblia unique?

It’s preserved in both formalin and PVA

What is the only difference between E. hystolytica and E. hartmanni?

Size.

Describe the internal structure of Blastocystis species. 

A large central vacuole surrounded by up to 6 nuclei

How are Blastocystis species reported?

Semiquantitated.

Few: < 2/oif

Moderate: 3-9/oif

Many: > 10/oif

How many nuclei do E. coli trophozoites contain? How many nuclei do E. coli cysts contain?

1. One

2. > four

How does the cytoplasm look in E. coli?

Dirty that is course and vacuolated

How do the chromatoid bodies look in E. coli?

Irregular with splintered ends

How do the chromatoid bodies appear in E. hystolytica?

Rounded ends

What color does trichrome stain the nucleus of E. nana?

Red

How does the nucleus look in E. nana?

1. No peripheral chromatin

2. Large, blot-like karyosomes in cysts

Does E. nana have chromatoid bodies?

No

How is Iodamoeba buetschlii similar to E. nana?

1. Size

2. Red nucleus with no peripheral chromatin

How is Iodamoeba different than E. nana?

1. Refractile granules surround nucleus

2. Cytoplasm is vacuolated with food and debris (troph)

3. Large glycogen vacuole in cysts

What parts of Giardia lamblia are seen in trichrome staining?

1. Two large nuclei

2. Sucking disks

How many flagella do Giardia lamblia trophs contain?

8

How many flagella does Chilomastix mesnili have and where are they located?

Three flagella on anterior end

What shape are Chilomastix mesnili cysts?

Lemon shaped

How many nuclei do Dientamoeba fragilis species have?

One or two

How many granules does Dientamoeba fragilis have?

4-8

What kind of pseudopodia does Dientamoeba fragilis contain?

Transparent

Does Dientamoeba fragilis have peripheral chromatin?

No

What two organisms have no known cyst stage?

1. Dientamoeba fragilis

2. Trichomonas vaginalis

How many flagella does Trichomonas vaginalis have, and where are they located?

5 flagella (four at anterior and one at posterior end)

What shape are Trichomonas trophs?

Pyriform

What is the internal structure of Trichomonas vaginalis?

Single, large nucleus at anterior end containing chromatin granules and a small lysosome

What is easily identifiable in Balantidinium coli? What is not easily identifiable?

1. Identifiable: Large macronucleus

2. Obscure: small micronucleus and cytosome

The cilia on a Balantinium coli trophozoite are located where?

Only on the outside wall

Describe the internal structure of Blastocystis species.

Large central body resembling vacuole with surrounding nuclei and inclusion bodies

What color does the central body in blastocystis species stain with trichrome?

Green

What color do the nuclei and surrounding inclusion bodies stain in blastocystis species with trichrome?

Red

Out of all the study organisms, which are pathogenic?

1. Entamoeba hystolytica

2. Blastocystis hominis

3. Trichomonas vaginalis

What is the difference in motility between E. hystolytica and E. coli?

E. hystolytica has rapid, unidirectional movement while E. coli has non-directional movement

Which organism is said to contain a basket nucleus with chromatin granules on one side?

Iodamoeba butschlii

What color do the vacuoles in blastocystis species stain with trichrome?

Red or blue

Ingestion of RBC’s is diagnostic of which organism?

Entamoeba histolytica

What is the difference in the karyosome of E. histolytica and E. coli?

1. The karyosome of E. histolytica is central

2. The karyosome of E. coli is eccentric

What can Giardia lamblia often be confused with?

An Entamoeba species with chromatoidal bars

How do you differentiate Giardia from Entamoeba species?

Giardia has a larger karyosome

How are E. nana and Iodamoeba buetschlii similar?

They both have no peripheral chromatin and a halo surrounding the nucleus

What is the smallest amoeba in the human intestine?

E. nana

What is the difference between E. nana and E. hartmanni?

E. hartmanni’s nucleus is bigger and lighter in color than E. nana’s. It also has peripheral chromatin whereas E. nana’s does not.

What is similar between E. nana and E. hartmanni?

Size and cytoplasm characteristics

How many nuclei does E. nana’s cysts have?

4

All the flagellates fall into what size range?

5-25 um

What size is the cyst of Neobalantidium coli?

45-70 um

What is the size of the troph of Neobalantidium coli?

50-100 um

Group the following species of amoebas and stages according to size (< 12 um max, < 20 um max, < 50 um max, < 60 um max):

a. Entamoeba hystolytica

b. Entamoeba hartmanni

c. Entamoeba coli

d. E. nana

e. Iodamoeba buetschlii

1. E. histolytica (< 60 um max)

2. E. coli (< 50 um max)

3. I. buetschlii (< 20 um max)

4. E. hartmanni (< 12 um max)

5. E. nana (< 12 um max)