Microbiology: Protozoa Flashcards

Entamoeba histolytica cyst- note the nuclei

Entamoeba histolytica Mature cyst- note the 4 nuclei

Entamoeba histolytica Trophozoite- endosome also called karyosome

Scanning Electron Micrograph of Giardia lamblia

Giardia lamblia trophozoites

Giardia lamblia Cyst
Cysts are kind of oval- Mature cysts have 4 nuclei and immature cysts have 2

Trichomonas vaginalis (Trophozoite look at shape)
five flagella. The Large nucleus is located toward the wide front.

Trichomonas vaginalis
Note large nucleus, flagella, and undulating membrane

Trypanosoma brucei

Trypanosoma brucei gambiense (Trypomastigotes stage)

a type of T. brucei that you can look at for characteristics similar in all. Gambiense is pathogenic, other T. brucei are not though.

Plasmodium falciparum

Plasmodium vivax

Balantidium coli cyst
Note large ‘dumbell shaped” macronucleus (arrow)

Toxoplasma gondii tachyzoites (yes tachyzoite) synonymous with trophozoite

Toxoplasma gondii cyst- from host brain tissue(it's also stained)

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Phylum: Sarcomastigophora (the amoeboflagellates)
Subphylum: Sarcodina (moves by pseudopodia)

Features: Trophozoite has 1 nucleus, Cyst up to 4. If you see more than 4 nuclei on cyst, its not E. histolytica. Non pathogenic amoebas have up to 8, etc but they are not E. histolytica.

Diseases: Amoebic dysentery * by fecal oral route

Phylum: Ciliophora
Features: Balantidium have 2 nuclei. One large sausage shaped and a small one right next to it. sometimes you can't see the micronucleus.
Diseases: Balantidiasis * by fecal oral route

Phylum: Sarcomastigophora (the amoeboflagellates)
Subphylum: Mastigophora (moves by flagellae) Though some have undulating membrane ex: trichomonas vaginalis.

Features: Giardia lambia trophozoites have long tapering posterior. 2 nuclei with small karyosomes. 4 pairs of flagella and a sucking disc.(see pic on reverse side)

Diseases: Giardiasis (Giardia intestinalis)* fecal oral route

Phylum: Sarcomastigophora (amoeboflagellates)
subphylum: Mastigiphorum (moves by flagella)
Features: Trichomonas vaginalis have undulating membrane and 4 anterior flagella. Trophozoite is the only stage of it' life.
Diseases: Trichomoniasis (vulvovaginitis) *by sexual contact

Phylum: Sarcomastigophora (amoeboflagellates)
Subphylum: Mastigophora (moves by flagella)
Features: Trypanosoma brucei have undulating membrane and central nucleus. some T. brucei subspecies are pathogenic, some not. T. brucei gambiense and T. brucei rhodesiense produce African sleeping sickness

Diseases: African Sleeping sickness *the Tsetse fly

Epimastigote- stage of life cycle where T. brucei multiplies inside Tsetse fly
Trypomastigote- stage of life cycle where T. brucei is transmitted to the human host through tsetse fly bites.

Phylum: Ampicomplexans (Sporozoa)
Features: 4 Species of Plasmodium cause malaria
P. vivax
P. malariae
P. falciparum
P. ovale
Diseases: Malaria * (female) Anopheles mosquito

Sporozoite- stage where pathogen is introduced into human host during a bite from anopheles mosquito.

Merozoite- stage where sporozoits infect liver cells and produce the asexual merozoite stage. Merozoits are released from lysed liver cells & enter the blood & infect erythrocytes.

Hence, the symptoms of malaria- chill, nausea, vomiting and headache are symptoms corresponding to rupture of erythrocytes.

Gametocytes- stage called the sexual phase or sexual life cycle. 1) Merozoites enter erythrocytes and differ into male or female gametocytes. 2) Continues when ingested by a female Anopheles mosquito during a blood meal. the zygote eventually develops into a cyst within the gut wall of the mosquito.

P. Falciparum= the most severe type of infections

Phylum: Ampicomplexans (Sporozoans-reproductive cells known as spores)

Features: Toxoplasma gondii have bow shaped cells and prominent nuclei. The sexual phase occurs in the lining of cat intestines where oocysts are produced and shed in the feces.

Diseases: Tosoplasmosis *by Inhailing/ ingesting cyssts from feces of infected cats...or ingesting raw meat of infected animals.

oocyst- a stage in the development of sporozoa consisting of a zygote enclosed by cyst wall. Oocysts of malarial parasites are found in the stomachs of infected mosquitoes. Oocysts of toxoplasma organisms are contained in the feces of infected cats.