Introduction to Virology and Parasitology

Question 1

What is mutualism in symbiosis?

Answer 1

Mutualism is a type of symbiosis where both organisms involved benefit.

Question 2

What is commensalism in symbiosis?

Answer 2

Commensalism is a type of symbiosis where one organism benefits, but the other is not harmed or affected.

Question 3

What is parasitism in symbiosis?

Answer 3

Parasitism is a type of symbiosis where one organism benefits at the expense of the other.

Question 4

What is a definitive host (DH)?

Answer 4

A definitive host supports the adult or sexually reproductive form of a parasite.

Question 5

What is an intermediate host (IH)?

Answer 5

An intermediate host supports the immature or non-reproductive forms of a parasite.

Question 6

What is a paratenic host (PH)?

Answer 6

A paratenic host acts as a substitute intermediate host, aiding in transmission without development of the parasite.

Question 7

What does the formula C = M + E + T stand for in integrated parasite control?

Answer 7

Control = Management + Epidemiology + Treatment.

Question 8

Why is management important in parasite control?

Answer 8

Clean, healthy animals in a controlled environment are less likely to encounter or be infested by parasites.

Question 9

Why is epidemiology important in parasite control?

Answer 9

Understanding the specific transmission, lifecycle, and environmental preferences of each parasite aids in control.

Question 10

Why should treatment not be solely relied upon for parasite control?

Answer 10

Parasites develop resistance quickly, making it crucial to use a combination of control methods.

Question 11

Name the major parasite assemblages.

Answer 11

Protists (protozoa), Nematodes (roundworms), Trematodes (flukes), Cestodes (tapeworms), Arthropods (crustaceans, insects, arachnids).

Question 12

What are ectoparasites?

Answer 12

Ectoparasites are parasites that live on the external surface of the host (e.g., ticks).

Question 13

What are endoparasites?

Answer 13

Endoparasites are internal parasites that live inside organ systems, digestive tracts, or blood (e.g., nematodes).

Question 14

What are permanent parasites?

Answer 14

Permanent parasites remain on the host for their entire lifecycle (e.g., lice).

Question 15

What are temporary parasites?

Answer 15

Temporary parasites only associate with the host briefly during their lifecycle (e.g., mosquitoes).

Question 16

What are obligate parasites?

Answer 16

Obligate parasites are entirely dependent on the host for survival (e.g., fleas).

Question 17

What are facultative parasites?

Answer 17

Facultative parasites can live without a host but can become parasitic under certain conditions (e.g., blowflies).

Question 18

What is Giardia lamblia?

Answer 18

Giardia lamblia is a flagellate protist that causes giardiasis, a diarrheal illness.

Question 19

How is Giardia transmitted?

Answer 19

Giardia is transmitted through contaminated surfaces, soil, food, or water, often from feces of infected humans or animals.

Question 20

Why are nematodes significant endoparasites?

Answer 20

Nematodes are significant because they cause major economic losses in livestock industries, such as sheep and wool.

Question 21

Describe the general lifecycle of nematodes.

Answer 21

Nematodes have a direct lifecycle: eggs hatch in the environment, larvae develop to infective stage (L3), ingested by host, mature to adults inside the host.

Question 22

What are the disease-causing stages of cestodes?

Answer 22

Both adult intestinal tapeworms and larval cysts can cause disease depending on the species involved.

Question 23

Which fluke is the most important and causes serious disease?

Answer 23

Liver fluke (Fasciola hepatica) is the most important fluke, causing serious disease in livestock.

Question 24

What are the key strategies for liver fluke control?

Answer 24

Strategies include strategic anthelmintic treatment, reducing intermediate host snails, and managing fluke-prone areas.

Question 25

What is the lifecycle of ticks?

Answer 25

Ticks have a lifecycle involving egg, larva (6 legs), nymph (8 legs), and adult (8 legs).

Question 26

What are some pathogenesis effects of ticks?

Answer 26

Ticks can cause anemia, irritation, allergic reactions, transmission of diseases, and toxin production.

Question 27

What is the life cycle of Ixodes holocyclus (paralysis tick)?

Answer 27

Ixodes holocyclus has a 3-host lifecycle, natural hosts are bandicoots, lifecycle may take up to 2 years, female lays 2000-3000 eggs.

Question 28

What is the main period of infection for Ixodes holocyclus?

Answer 28

The main period of infection is spring, with a secondary peak in autumn.

Question 29

What is the significance of Lucilia cuprina?

Answer 29

Lucilia cuprina is responsible for at least 90% of fly strikes in sheep, causing significant economic loss.

Question 30

How can fly strikes in sheep be controlled?

Answer 30

Control measures include Mules operation, worm control, crutching, jetting, tail docking, breeding for resistance, treating strikes, removing carrion, and traps.