Introduction to Parasitology and Soil-Transmitted Helminths

Question 1

What are the types of parasites based on location?

Answer 1

Endoparasite and Ectoparasite

Question 2

What are the types of parasites based on life cycle?

Answer 2

Obligatory and Facultative

Question 3

What are the types of parasites based on time frame?

Answer 3

Temporary and Permanent

Question 4

Give examples of viruses with definitive hosts.

Answer 4

Malaria and Schistosoma

Question 5

Define: Definitive Host

Answer 5

Host harbours the sexually mature form of the parasite.

Question 6

Define: Intermediate Host

Answer 6

Host harbours the asexual or larval stage of the parasite.

Question 7

Give examples of intermediate hosts.

Answer 7

Snails - Schistosoma and Fasciola

Crabs - Paragonymous

Question 8

Define: Paratenic Host

Answer 8

Host harbours parasite but no development occurs.

Question 9

Define: Accidental Host

Answer 9

Host is not suitable for the development of the parasite.

Question 10

Give examples of accidental hosts.

Answer 10

Humans - Ancylostoma caninum and some tapeworms and hookworms

Question 11

Define: Reservoir

Answer 11

“Back-up” host of the parasite

Question 12

Give examples of reservoirs.

Answer 12

Cattle - Schistosoma japonicum

Rats - Yersinia pestis

Question 13

Define: Vector

Answer 13

Agent that transmits a pathogen from one organism to another.

Question 14

Give examples of vectors.

Answer 14

Malaria - Anopheles sp.

Question 15

What are the types of parasite life cycles with respect to the number of hosts needed?

Answer 15

Direct and Indirect

Question 16

Define: Direct Life Cycle

Answer 16

Only one host needed

Question 17

Define: Indirect Life Cycle

Answer 17

More than one host species required

Question 18

Give examples of parasites undergoing a direct life cycle.

Answer 18

1. Entamoeba sp.
2. Trichomonas sp.
3. Oricularis sp.
4. Ringworms
5. Pinworms
6. Soil-transmitted Helminths

Question 19

Enumerate the types of parasitic transmission.

Answer 19

1. Direct
2. Soil-transmitted
3. Water-borne
4. Food-borne
5. Vector-borne

Question 20

Entamoeba histolytica exhibits what type of transmission?

Answer 20

Water-borne

Question 21

T/F

Schistosoma sp. is transmitted via water

Answer 21

F

Question 22

Give examples of organisms that are transmitted via food.

Answer 22

1. Taenia saginata
2. Ascaris sp.
3. Trichuris sp.
4. Capillaria
5. Paragonymous

Question 23

Why can’t STH reproduce endlessly in the host?

Answer 23

Host must be exposed repeatedly to the infective stage.

Question 24

What cytokines do TH1 cells release?

Answer 24

IL-2, IFN-gamma, and TNF-beta

Question 25

What cytokines do TH2 cells release?

Answer 25

IL-3, IL-4, IL-5, and IL-10