Unit 4 section 1. Chapter 5.1:

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which organism is responsible for African Sleeping Sickness?

Trypanosoma brucei (correct)

Plasmodium falciparum

Trypanosoma cruzi

Toxoplasma gondii

What is the primary vector for Chagas disease?

Kissing bug (correct)

Anopheles mosquito

Tsetse fly

Aedes mosquito

What symptom is commonly associated with Toxoplasmosis in immunocompromised individuals?

Coma

Organ failure (correct)

Severe fever

Confusion

Which drug is known to treat multidrug-resistant malaria?

Artemisinin Signup and view all the answers

What is the primary process by which sporozoites develop in the mosquito's liver?

Schizogony Signup and view all the answers

What symptom is commonly observed in African Sleeping Sickness?

Sleep disturbances Signup and view all the answers

Which of the following drugs inhibits DNA synthesis in protozoa?

Nitroimidazoles Signup and view all the answers

Which vector is responsible for transmitting the organism Trypanosoma cruzi?

Kissing bug Signup and view all the answers

How does Aminoquinolines function in treating protozoal infections?

Disrupts hemoglobin breakdown Signup and view all the answers

What is a common symptom of Chagas disease?

Swelling at bite site Signup and view all the answers

What is the primary function of the contractile vacuole in protozoa?

Regulates water by expelling excess Signup and view all the answers

Which life cycle stage of protozoa is known for being the dormant stage?

Cyst Signup and view all the answers

What distinguishes amoebas from other protozoan groups?

Use of pseudopodia for movement Signup and view all the answers

Which of the following protozoa is classified as an apicomplexan?

Plasmodium vivax Signup and view all the answers

What feature is common to all excavata protozoa?

Presence of flagellar structures Signup and view all the answers

What is the infectious stage of a protozoan called that is often transferred to a host?

Sporozoite Signup and view all the answers

What type of slime mold develops into mobile slugs that later form fruiting bodies?

Cellular slime molds Signup and view all the answers

What is the primary effect of the organism Phlebotomus in relation to protozoan diseases?

Transmits leishmaniasis Signup and view all the answers

What structural feature do ciliates possess that is critical for their movement?

Cilia Signup and view all the answers

Which of these protozoan diseases is characterized by gastrointestinal symptoms and caused by Trichomonas vaginalis?

Trichomoniasis Signup and view all the answers

Study Notes

Unicellular Eukaryotic Parasites (Protozoa)

Protozoa are single-celled eukaryotic organisms.
Found in aquatic and terrestrial environments.
Are aerobic heterotrophs, needing oxygen and organic compounds for energy.
Exhibit two main life cycle stages:
- Trophozoite: Active feeding and growth stage.
- Cyst: Dormant stage.

Protozoan Structural Features

Contractile vacuole: A star-like structure regulating water balance by expelling excess water.
Pseudopodia: "Arms" of the cell used for movement and anchoring.
Kinetoplastid: Specialized mitochondria.

Protozoan Life Cycle Stages

Trophozoite: Active feeding and growth stage.
Cyst: Dormant stage.
Sporozoite: Infectious stage transferred to a host.
Merozoite: Product of nuclear division, often infecting host cells.
Gametocyte: Reproductive cell stage.

Protozoa Classification

Protozoa are classified based on their movement structures (e.g., flagella, pseudopodia, or lack of motility).

Amoebas

Single-celled organisms, primarily free-living in freshwater.
Use pseudopodia for movement and capturing bacteria.
Types:
- Entamoeba histolytica: Causes amoebiasis.
- Naegleria fowleri: Causes brain infection.

Slime Molds

Two types:
- Cellular slime molds: Form mobile "slugs" that develop into fruiting bodies producing haploid spores (e.g., Dictyostelium discoideum).
- Plasmodial slime molds: Large multinucleate cells forming reproductive stalks and producing spores (e.g., Fuligo septica).

Apicomplexans

Non-motile and parasitic.
Possess an apical complex for penetrating host cells.
Display a ring stage within red blood cells (RBCs).
Types:
- Plasmodium vivax: Causes malaria (pink circles in RBCs).
- Toxoplasma gondii: Causes toxoplasmosis (purple crescents).

Ciliates

Examples:
- Balantidium coli: Causes balantidiasis.
- Paramecium: Non-pathogenic.

Excavata

Group of protozoa classified based on flagellar structures.
Examples:
- Fornicates: Giardia lamblia, Giardia intestinalis.
- Parabasalids: Trichomonas vaginalis, Trichonympha.
- Euglenozoans: Trypanosoma brucei gambiense, Trypanosoma cruzi.

Protozoan Diseases and Life Cycles

Leishmaniasis: Disfiguring skin disease; transmitted by sandflies (Phlebotomus).
Trichomoniasis: Vaginal discomfort, transmitted through sexual contact.
Malaria: Fever, chills, transmitted by mosquitoes (Plasmodium species).
- Mosquito injects sporozoites into liver
- Liver cells divide forming merozoites
- Merozoites infect red blood cells, releasing more merozoites
- Some merozoites develop into gametocytes, completing life cycle in mosquito.
African Sleeping Sickness: Sleep disturbances, transmitted by tsetse flies (Trypanosoma brucei).
Chagas Disease: Fever, transmitted by kissing bugs (Trypanosoma cruzi).
Toxoplasmosis: Often asymptomatic, transmitted through undercooked meat or contaminated cat feces (Toxoplasma gondii).

Anti-Protozoal Drugs

Stibogluconate: Disrupts protozoal metabolism.
Nitroimidazoles: Inhibit DNA synthesis.
Aminoquinolines: Accumulate in parasitized RBCs, disrupting hemoglobin breakdown.
Artemisinin: Treats multidrug-resistant malaria in severe cases.