Parasitology - Lecture 1

Question 1

What is the basic morphology of Nematodes

Answer 1

• Cylindrical, elongated, tapered at both ends, bilaterally symmetrical
• separate sexes
• anterior end: identical in both genders
• posterior end: males has variation, females are simple

Question 2

What is a Temporary Parasite?

Answer 2

visit the host for a blood meal and leave

Question 3

What is a Permanent Parasite?

Answer 3

exist outside the host for only a short time while in transition

Question 4

What is an obligate parasite?

Answer 4

need a host to complete its lifecycle and survive

Question 5

What is a Facultative Parasite?

Answer 5

normally free living but can invade the host under certain conditions

Question 6

What is Polyparasitism?

Answer 6

When a host is infected with multiple species of parasite

Question 7

What is hyperparasitism?

Answer 7

when a parasite has parasites

Question 8

What is a direct lifecycle?

Answer 8

transmission of the parasite from one host to the next occurs among members of the same species

Question 9

What is an indirect lifecycle?

Answer 9

transmission occurs between different species

Question 10

What is a definitive host?

Answer 10

the host where parasites reach sexual maturity

Question 11

What is an Intermediate host?

Answer 11

host required for development but where parasites do not reach sexual maturity

Question 12

What is found within the hypodermis?

Answer 12

hypodermal chords: 4 thickened portions that contain longitudinal nerves and excretory canals

Question 13

Describe the general anterior end of nematodes

Answer 13

• Identical in M and F
• mouth
• buccal capsule

Question 14

What structures may be associated with the mouth of a nematode?

Answer 14

lips, teeth, cutting plates, leaf crowns

Question 15

Describe the posterior end of general female nematodes

Answer 15

normally very simple

Question 16

Describe the posterior end of male nematodes from Order Strongylida

Answer 16

• copulatory bursa

- has 2 spicules

Question 17

Describe the posterior end of male nematodes from Order Ascaridida

Answer 17

blunt, ventrally curved provided with 2 spicules

Question 18

Describe the posterior end of male nematodes from Order Spirurida

Answer 18

coiled with 2 spicules

Question 19

Describe the posterior end of male nematodes from Superfamily Trichuroidea

Answer 19

coiled with one spicule

Question 20

Describe the general digestive system of nematodes

Answer 20

• complete with a mouth and an anus.
• oesophagus, pharynx, intestine, rectum, anus.
• in males, anus opens in cloaca

Question 21

What is a buccal capsule?

Answer 21

anterior enlarged portion of buccal cavity with heavily sclerotised walls

Question 22

What are the main shapes of the oesophagus?

Answer 22

• Filariform/ strongyliform
• Rhabtitiform
• bulb shaped

Question 23

Describe the reproductive system of male nematodes

Answer 23

• have spicules (copulatory structures)
• testes, seminal vesicles, vas deferense, etc.
• spicules inserted into vulva
• shape of spicules important for ID

Question 24

Describe the reproductive system of female nematodes

Answer 24

• ovaries, oviduct, uterus, vagina, vulva
• can have one two or more ovaries
• ovijector: musclular terminal that forces eggs into the vagina

Question 25

Describe the nervous system of nematodes

Answer 25

• CNS: nerve ring surrounds oesophagus

- nerve fibres extend longitudinally and innervate major structures

Question 26

What are the four layers of nematode eggs

Answer 26

(From outside to inside)

1. uterine/ proteinacious layer (not always present)
2. Vitilline Layer
3. Chitinous Layer
4. Lipid Layer

Question 27

What are the two phases of nematode development?

Answer 27

Phase 1: L1-L3 occurring in the environment

Phase 2: L3-adult occurring in the host

Question 28

What does oviparous mean?

Answer 28

female deposits eggs

Question 29

What does ovoviviparous mean?

Answer 29

female deposits eggs that contain larve