PROTOZOANS: FLAGELLATES

Flagellates (Mastigophora) are protozoan parasites characterized by the presence of one or more flagella, a whip-like structure which they use for movement.

G. intestinalis and G. duodenalis

Other name for Giardia Lamblia

Giardia Lamblia (Giardiasis)

Causes Traveler’s diarrhea worldwide; from drinking natural water sources

shed irregularly

Cysts or trophozoites of Giardia Lamblia in stool are diagnostic or on a sigmoidoscopy specimen but they ________ so parasites may not appear in every sample. It is recommended to collect three stool samples on different days for an accurate diagnosis.

light-colored

Asymptomatic or GI symptoms can be severe Giardia Lamblia and can cause __________ stools.

10 to 36 days; self-limiting

Incubation time of Giardia Lamblia, and it can be ________

safe water, hygiene, and proper hand washing

Preventive measures for Giardia Lamblia infections

Giardia Lamblia

Flagellate Cysts:

• One to four nuclei

• Four axonemes, which are part of the internal flagellar structure

• Four median bodies

• Significance: highly resistant to environmental conditions, allowing it to survive outside the host.

Giardia Lamblia

Flagellate Trophozoite:

• Pear-shapes

• Two nuclei with a large central karyosome

• Four pairs of flagella

• Anterior and Ventral Sucking Disks to attach to the intestinal lining.

Giardia Lamblia

“Old man in glasses”

Giardia Lamblia

Trophozoite has falling leaf motility

Pathogenic (intestinal infection and diarrhea)

Pathogenic/Non-pathogenic: Giardia Lamblia

Non-pathogenic

Pathogenic/Non-pathogenic: Chilomastix mesnili

Commensal; usually found in the cecum

What relationship does Chilomastix mesnili have with humans and where does it typically reside?

Chilomastix mesnili

Flagellate Cysts:

• Round with a bulge at the anterior

• Single large nucleus

• Hourglass-shaped cytostome and prominent fibirils

• “Lemon-shaped cyst”

Chilomastix mesnili

Flagellate Trophozoite:

• Three flagella at the anterior; one at the posterior (4 in total)

• Spiral groove running the length of the body

• Prominent cytostome bordered by fibrils

• Single nucleus at the anterior

• Stiff rotary motility “Chilomastic Twirl”

Commensal

What relationship does Trichomonas hominis have with humans?

Trichomonas hominis

No known cyst form but its trophozoites in stool are diagnostic where ingestion is via fecal-oral transmission.

Trichomonas hominis

Flagellate Trophozoite:

• One nucleus, four flagella, undulating membrane

• Prominent axostyle extending through the posterior

• Undulating membrane runs the entire length of the body along the costa

• One oval nucleus with a small karyosome

Trichomonas hominis

Trophozoite movement is active and wave-like due to the undulating membrane

Pathogenic

Pathogenic/Non-pathogenic: Trichomonas vaginalis

Trichomonas vaginalis

Only flagellate in the urogenital tract

sexual

Mode of transmission of Trichomonas vaginalis

Vaginitis with yellow discharge

Effect of Trichomonas vaginalis in females is?

asymptomatic urethritis

Effect of Trichomonas vaginalis in males is?

Trichomonas vaginalis

No known cyst form but Trophozoites in urine, vaginal secretions, and urethral secretions are diagnostic

Trichomonas vaginalis

Only flagellate in the urogenital tract

jerky

Trichomonas vaginalis is diagnosed by wet mount method, which would show that the parasite has ____ motility. Culture, rapid antigen tests, and PCR (often have higher sensitivity than the wet mount)

Trichomonas vaginalis

Flagellate Trophozoite:

• Four anterior flagella

• An undulating membrane that extends half the body length

• Contains a single nucleus with a small karyosome

• Movement: active jerking motility

Metronidazole

Recommended for the treatment of urogenital trichomoniasis, although resistance to both metronidazole and other 5-nitroimidazoles has been reported.

simultaneously

For urogenital trichomoniasis, it is recommended that all sexual partners be treated ________ to avoid immediate reinfection.