Parasitology L1, L2, & L3

Question 1

an organism whose environment during all or part of its lifecycle is provided by another organism of a different species (host) and obtains all or parts of its nutritional requirements from the host’s bodily fluids or tissues

Answer 1

Parasite

Question 2

the host in or on which the adult parasite resides and reproduces & reaches sexual maturity on the host

Answer 2

definitive host

Question 3

a host is essential to the parasites lifecycle in which it undergoes development to juvenile stage but NOT mature stage

Answer 3

intermediate host

Question 4

a host is optional to the parasites lifecycle in which juvenile stages may persist but do not develop

Answer 4

paratenic host

Question 5

a cycle which is completed without participation of an intermediate host

Answer 5

direct life cycle

Question 6

a cycle which is completed with participation of an intermediate host

Answer 6

indirect life cycle

Question 7

the time elapsing between the initiation of infection of a definitive host and the appearance of the products of reproduction of parasite (ex: eggs)

Answer 7

Pre-patent period

Question 8

direct evidence of the organism can be detected (ex: in the patients feces, blood, or secretions regardless if symptoms have appeared – can be subclinical

Answer 8

patent infection

Question 9

parasite living in the organs or tissue inside the host – typically soft bodied (roundworms, tapeworms)

Answer 9

endoparasite

Question 10

Endoparasites fall into 2 major types:

Answer 10

1) those that wholly reside within the body tissues (canine heart worm, migratory parasite larvae)
2) those that reside on the external luminal side of the epithelial barriers (majority of gut worms lung worms)

Question 11

parasite living on the integument (outside) of the host usually air breathing (flies, fleas, lice, mites)

Answer 11

ectoparasite

Question 12

parasite whose lifecycle cannot be completed without a parasitic phase at some stage or other so without a host there’s no survival

Answer 12

obligatory parasite

Question 13

parasite whose lifecycle can be completed without a parasitic phase but may optionally include a parasitic phase under some circumstances (ex: free-living option or parasitic when chance arises or conditions are adverse)

Answer 13

facultative parasite

Question 14

the whole story of a parasite (from one adult stage to the next) adult to adult, via egg, immature stages,

-often separate infectious and dispersal stages

Answer 14

lifecycle

Question 15

the specific stage in the lifecycle of a parasite that is able to initiate infection in a definitive or immediate host

Answer 15

infective stage

Question 16

the route by which a parasite gains entry to a host (i.e. ingestion, skin penetration, injection)

Answer 16

Route of infection

Question 17

the route some parasites follow in the body of the host after they have gained entry and before they have developed to maturity

Answer 17

route of migration

Question 18

a stage in the lifecycle of a parasite which exists free in the general environment – not in the host animal

Answer 18

free living stage

Question 19

Distinguish the taxonomic word endings for:

ORDER

Answer 19

ends with -IDA

ex: Order Strongylida

Question 20

Distinguish the taxonomic word endings for:

SUPERFAMILY

Answer 20

ends with -OIDEA

ex: Superfamily trichostrongyloidea

Question 21

Distinguish the taxonomic word endings for:

FAMILY

Answer 21

ends with -IDAE

ex: Family tristrongylidae

Question 22

Distinguish the taxonomic word endings for:

SUBFAMILY

Answer 22

ends with -INAE

Subfamily trichostrongylinae

Question 23

List the 4 ways a nematode can gain entry into a definitive host and what stage does it happen?

Answer 23

Happens at infective stage

1) ingestion
2) skin penetration
3) injection
4) transplacental migration

Question 24

All nematodes have ___ stages in the lifecycle

Answer 24

6

Question 25

When are intermediate hosts infected in nematodes?

Answer 25

L1 – VERY RARELY L2

Question 26

Discuss the basic lifecycle of a nematode

Answer 26

Step 1) female produces eggs containing an embryo

Step 2) embryo develops into first larval stage (L1)

Step 3) Embryo moults/sheds cuticle to the second stage (L2)

Step 4) Embryo moults/sheds cuticle to the third stage (L3)

Step 5) Embryo moults/sheds cuticle to the fourth stage (L4)

Step 6) embryo moults/ sheds cuticle and matures to adult stage

growth occurs after each stage

Question 27

When a nematode infects a host by skin penetration, by which routes would you think it could migrate to the small intestine where it matures?

Answer 27

the blood stream since its the simplest and most rapid means of distribution anywhere in the body

Question 28

if a mammal acts as an intermediate host or paratenic host for a nematode, what does this tell you about the definitive host?

Answer 28

typically carnivores as they are eating the intermediate host as part of its normal/prey