Parasitology: Protozoa

Question 1

What are the 4 classes of protozoa?

Answer 1

1. Amoebae (pseudopodia)
2. Flagellates (flagella)
3. Ciliates (cilia)
4. Apicomplexans (gliding)

Question 2

Describe the life cycle of Entamoeba histolytica:

Answer 2

protozoa, fecal-oral, DIRECT

Question 3

What are the 5 means of damage to the host by protozoa? Give examples.

Answer 3

1. Mechanical (Giardia-barrier to fat absorption, Plasmodium)
2. Competition for host resources (Plasmodium- glucose)
3. Cytotoxicity (Entomoeba histolytica- releases liver enzymes that degrade liver)
4. Inflammation (Plasmodium- cytokines)
5. Inflammation (Leishmania- Th mediated damage)

Question 4

What do Giardia do to harm the host?

Answer 4

prevent absorption of nutrients–> diarrhea

Question 5

How does Entomoeba histolytica harm host?

Answer 5

Liver abscesses –> cytotoxicity to liver, chews through liver by releasing enzymes

Question 6

What tests are done to confirm protozoa infection?

Answer 6

1. direct examination (Stool protozoa, Plasmodium)
2. Culture (Leishmania)
3. Antigen detection (Plasmodium-RDT, E. hystolitica)
4. Host antibody detection (E. histolytica, Trypnasomes)
5. Nucleic acid amplification (blood and tissue protozoa)
6. Radiologic (amoebic liver abscess)

Question 7

What are the medical treatments for protozoa infection?

Answer 7

1. Antibiotics (giardia, plasmodium-doxycyclin)
2. Antifungals (Leishmania- azoles, flucanazol)
3. Conventional anti-parasitics (all protzoa)
4. Herbs/plant extracts (Plasmodium)
5. Elements (Leishmania)

Question 8

What are the international treatments for protozoa infection?

Answer 8

Percutaneous drainage (entamoeba histolytica abscess)

Question 9

What is the life cycle of Leishmania?

Answer 9

Protozoa, vector-borne, INDIRECT (sandfly)

Question 10

What is the clinical correlate of Leishmania?

Answer 10

skin ulcer (really bad to face!)

Question 11

Where are oligoparasitic protozoa found?

Where are polyparasitic protozoa found?

Answer 11

• Oligoparasitic: mucocutaneous, cutaneous (CMI inc)

- Polyparasitic: diffuse cutaneous, visceral (Ab inc)

Question 12

What is the main cause of tissue injury in Leishmaniasis?

Answer 12

host-parasite interaction: IMMUNE mediated injury

Question 13

What is the 1st line therapy for Leishmaniasis?

Answer 13

Antimony (Sb, element)

Toxic! (cardiotoxic, hepatotoxic, nephrotoxic, haemotoxic, toxic to pancreas)

Question 14

What are the 4 main Rx for Leishmaniasis?

Answer 14

• ABs: Azithromycin, Paromomycin
• Antifungals: Flucanazole, Amphotericin
• Herbs/Plant: Garlic
• Elements: Pentavalent Antimony

Question 15

What is the life cycle of Malaria?

Answer 15

protozoa, vector-borne, INDIRECT

Question 16

How does P. Falciparum (malaria) cause host damage?

Answer 16

Obstruction of capillaries

Question 17

How is Malaria diagnosed?

Answer 17

• direct examination of blood film
• antigen detection: RDT= rapid diagnostic test
• nucleic acid amplification (PCR)

Question 18

How is Malaria caused by Plasmodium treated?

Answer 18

• ABs: Doxycycline, Clindamycin
• Conventional Antiparasitics: Chloroquine, Mefloquine (erythrocyte cycle)
• Herbs/Plants: Artemisinin, Quinine

Question 19

How is Malaria caused by P. ovale treated?

Answer 19

• Blood Schizonticide: Chloroquine, Atovaquone-Proguanil

- Tissue Schizontocide: Primaquine (radical cure)