Parasites & Antiparasitics

Question 1

Protozoa

Answer 1

Eukaryotic single-celled parasite

• 3 different types: amoeba, flagellates, sporozoa
• only has cell membrane no cell wall

Question 2

Helminths (Worms)

Answer 2

3 Main Types:

1. Nematodes (roundworms)
2. Cestodes (tapeworms)
3. Trematodes (flukes or flatworms)

Question 3

Ectoparasites

Answer 3

Arthropods (ticks, fleas, lice)

• considered macroscopic because we can see

Question 4

Life Cycle Stages of Protozoa

Answer 4

1. Trophozoites: motile, feeding, and reproducing forms.

2. Cysts: Non-motile, Non-feeding, and Non-reproducing forms. Surviving form in the environment through its thick wall.

Question 5

Life Cycle Stages of Helminths

Answer 5

Egg –> Larva –> Adult

• All helminths are pathogenic at larva and adult stage.
• only flukes are pathogenic at egg stage.

Question 6

Definitive Host

Answer 6

Host where the parasite completes the sexual phase.

Question 7

Intermediate Host

Answer 7

Host where the parasite lives asexually.

Question 8

Vector

Answer 8

The organism that transmits a parasite to a host.

Question 9

Reservoir

Answer 9

Host that serves as a source of parasite transmission to the population of interest.

Ex. human or animal

Question 10

Antiparasitic Agents

Answer 10

They target eukaryotic processes (parasites are eukaryotes), thus the potential for toxicity in humans.