7_Parasitic Protozoans

Protozoan parasites

are single-celled organisms that infect humans.

Entamoeba histolytica

• is one of the more important gastrointestinal pathogens to detect because of the invasive nature of the disease that it causes.

• may cause hepatic amoebic abscesses and, rarely, pleuropulmonary disease, in addition to ulceration in the colon.

• “ground-glass” appearance

• Cysts usually measure 12 to 15 µm;

• Tropozoites 15-20 µm

• 4 nuclei that characteristically have centrally located karyosomes in Cyst;

• Single nucleus in tropozoites

• uniformly distributed chromatin granunles peripheral chromatin in cyst and tropozoites

Giardia lamblia

• a is a flagellate of world-wide distribution.

• It is more common in warm climates than temporal climates.

• It is the most common flagellate of the intestinal tract, causing Giardiasis.

• Humans are the only important reservoir of the infection.

• The infection is most common in parts of the world where sanitation is at its lowest.

• Cysts usually measure 8-19 µm;

• Tropozoites 10-20 µm

• 4 nuclei in cysts

• 2 large nuclei in tropozoites

• With sucking disks;

• 8 flagella

Giardiasis

• is an infection of the upper small bowel, which may cause diarrhea

• Giardia lamblia is the most common flagellate of the intestinal tract, causing__

Balantidium coli

• is a large, ciliated protozoan found in the gastrointestinal tracts of humans, nonhuman primates, pigs, and cattle, although its normal host is pigs.

• Humans can acquire the infection via the fecal-oral route, and human-to-human transmission may also occur.

• Humans may remain asymptomatic, as does the pig, or may develop dysentery similar to that caused by Entamoeba histolytica

• Cysts usually measure 50 to 70 µm;

• Tropozoites 40-200 µm with cilia

• Bean shaped macronucleus;

• less conspicuous micronucleus

A.F.C.A/S

(Amoebae, Flagellates, Ciliate, Apicomplexans/Sporozoans)

Groups of intestinal protozoan parasites:

Amoebae

Groups of intestinal protozoan parasites:

• Entamoeba histolytica, Entamoeba coli, Iodamoeba butschlii and Endolimax nana

Flagellates

Groups of intestinal protozoan parasites:

• Giardia lamblia and Chilomastix mesnili

Ciliate

Groups of intestinal protozoan parasites:

• Balantidium coli

Apicomplexans/Sporozoans

Groups of intestinal protozoan parasites:

• Isospora belli, Cyclospora cayetanensis and Cryptosporidium

serology and sigmoidoscopy

Microscopic identification of cysts and trophozoites still remains to be an important part of the diagnosis for any of these infectious organisms, although other methods such as ___are also used

Endolimax nana

• Cysts usually measure 5 to 10 µm;

• Tropozoites 6-12 µm

• 4 small nuclei; centrally located karyosomes;

• Single nucleus in tropozoites, large irregularly shaped karyosome

• no peripheral chromatin in cyst and tropozoites

Iodamoeba butschlii

• Cysts usually measure 5 to 20 µm;

• Tropozoites 8-20 µm

• Single nucleus; eccentrically located karyosome

• large, irregular karyosome surrounded by chromatin granules, but it lacks uniformly distributed peripheral chromatin in both cysts and trophozoites

50 um

LPO size per box in stage micrometer

12.5 um

HPO size per box in stage micrometer

Chilomastix mesnili

• Tropozoites 6-24 µm;

• pear-shaped

• Single nucleus in tropozoites

4 nuclei

Mature Entamoeba histolytica/Entamoeba dispar mature cysts have ___

centrally located karyosomes

Mature Entamoeba histolytica/Entamoeba dispar mature cysts have 4 nuclei that characteristically have ___ and fine, uniformly distributed peripheral chromatin.

fine, uniformly distributed peripheral chromatin

Mature Entamoeba histolytica/Entamoeba dispar mature cysts have 4 nuclei that characteristically have centrally located karyosomes and ___

12 to 15 µm

Mature Entamoeba histolytica/Entamoeba dispar mature cysts have 4 nuclei that characteristically have centrally located karyosomes and fine, uniformly distributed peripheral chromatin. Cysts usually measure ___

15 to 20 µm (range 10 to 60 µm)

E. histolytica/E. dispar trophozoites usually measure ___, tending to be more elongated in diarrheal stool.

10–35 µm

Cysts of Entamoeba coli are usually spherical but may be elongated and measure

8 nuclei

mature cysts of Entamoeba coli have ___but may have as many as 16 or more

Entamoeba coli

is the only Entamoeba species found in humans that has more than four nuclei in the cyst stage.

glycogen

The cytoplasm of mature cysts of Entamoeba coli may contain diffuse ___

splinter like with pointed ends

Chromatoid bodies are seen less frequently than in E. histolytica. When present, they are usually ___, whereas the chromatoid bodies of E. histolytica have rounded ends.

rounded ends

Chromatoid bodies are seen less frequently than in E. histolytica. When present, they are usually splinter like with pointed ends, whereas the chromatoid bodies of E. histolytica have ___

15–50 µm

Trophozoites of Entamoeba coli usually measure __

large, eccentric karyosome and coarse, irregular peripheral chromatin

The trophozoites of Entamoeba coli have a single nucleus with a characteristically ____

coarsely granular and vacuolated (often described as “dirty” cytoplasm)

The cytoplasm of Entamoeba coli is usually

short and blunt

Pseudopodia of Entamoeba coli may be seen and are often ___; movement in living trophozoites is nondirectional

nondirectional

Pseudopodia of Entamoeba coli may be seen and are often short and blunt; movement in living trophozoites is ___

5–10 µm

Cysts of Endolimax nana vary from spherical to ellipsoidal in shape and measure ___

no peripheral chromatin

Mature cysts have four small nuclei with large, usually centrally located karyosomes and ___

iodine-stained wet mounts

The nuclei are not visible in unstained wet mounts but are visible in ___ and slides stained with trichrome or iron hematoxylin (i.e., permanent stains).

trichrome or iron hematoxylin

The nuclei are not visible in unstained wet mounts but are visible in iodine-stained wet mounts and slides stained with ___(i.e., permanent stains)

6–12 µm

Endolimax nana trophozoites measure___

lacks peripheral chromatin

The nucleus of Endolimax nana ___

granular

The cytoplasm of Endolimax nana is __ and often highly vacuolated and may contain inclusions of bacteria.

highly vacuolated

The cytoplasm of Endolimax nana is granular and often ___ and may contain inclusions of bacteria.

inclusions of bacteria

The cytoplasm of Endolimax nana is granular and often highly vacuolated and may contain _ _

5–20 µm

Cysts of Iodamoeba buetschlii vary from nearly spherical to ellipsoidal in shape and measure __

spherical to ellipsoidal

Cysts of Iodamoeba buetschlii vary from nearly ___in shape and measure 5–20 µm.

large compact mass (vacuole) of glycogen

An important diagnostic feature for Iodamoeba buetschlii species is the presence of a ____ in the cyst stage

darker, reddish-brown color

Iodamoeba buetschlii’s mass can be visible in unstained wet mounts, in iodine-stained preparations it takes on a ___

8–20 µm

Trophozoites of Iodamoeba buetschlii measure __

refractile, achromatic granules

Trophozoites of Iodamoeba buetschlii measure 8–20 µm and have a single nucleus with a large, usually centrally located karyosome surrounded by ___

bacteria, yeast, or other materials

The cytoplasm of Iodamoeba buetschlii is coarsely granular and vacuolated and can contain ___

sluggish and described as nonprogressive

Movement in living trophozoites of Iodamoeba buetschlii is ___

e 8-19 µm (average 10-14 µm)

Giardia duodenalis cysts are are oval to ellipsoid and measure ___

4, 2

Mature cysts of Giardia duodenalis have __ nuclei, while immature cysts have _

pear-shaped

Giardia duodenalis trophozoites are __

10-20 micrometers

Giardia duodenalis trophozoites are pear-shaped and measure __ in length

sucking disks

The ___ (used for attaching to the host’s mucosal epithelium), median bodies, and flagella (8) of Giardia duodenalis trophozoites may also be seen.

median bodies, and flagella (8)

The sucking disks (used for attaching to the host’s mucosal epithelium), ___ of Giardia duodenalis trophozoites may also be seen.

nonpathogenic

Chilomastix mesnili is a flagellated protozoan generally regarded as ___ in the human host.

6–24 µm

Trophozoites of Chilomastix mesnili are pear-shaped and usually measure __ in length

rounded and contains a single nucleus with an eccentric karyosome

The anterior end of Chilomastix mesnili is ___. The posterior end tapers off to a point.

tapers off to a point

The anterior end of Chilomastix mesnili is rounded and contains a single nucleus with an eccentric karyosome. The posterior end ___

stools

Both Balantidium coli trophozoites and cysts may be shed in

40 µm to 200 µm

Trophozoites of Balantidium coliare characterized by: their large size

cilia

the presence of __ on the cell surface of Balantidium coli trophozoites, a cytostome, and a bean shaped macronucleus which is often visible and a smaller, less conspicuous micronucleus.

cytostome

the presence of cilia on the cell surface of Balantidium coli trophozoites, a ___, and a bean shaped macronucleus which is often visible and a smaller, less conspicuous micronucleus.

the presence of cilia on the cell surface of Balantidium coli trophozoites, a cytostome, and a bean shaped macronucleus which is often visible and a smaller, less conspicuous micronucleus.

bean shaped macronucleus

the presence of cilia on the cell surface of Balantidium coli trophozoites, a cytostome, and a ___which is often visible and a smaller, less conspicuous micronucleus.

50 µm to 70 µm

Cysts of Balantidium coli are seen less frequently and range in size from ___

invade tissue

B. coli trophozoites can also ___