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Flashcards in Intro Deck (46):
1

What is the most dangerous animal on earth?

mosquito

2

What percentage of animal species are parasitic at some stage in their life?

50%

3

Which phylogenetic animal groups contain parasites?

All the major groups

4

What are some common parasites in North America?

pinworms, giardia, dog roundworms, toxoplasma, ticks

5

Where does the word 'parasite' come from?

Greek, meaning 'one who eats at the table others'

6

Are parasites prokaryoyes, eukaryotes, or both?

eukaryotes. therefore not bacteria or viruses

7

Define protozoa

unicellular organisms

8

Define metazoa

multicellular organisms

9

Give some examples of ectoparasites

head lice, ticks, fleas

10

Give some examples of endoparasites

hookworm, tapeworm, tapeworm eggs, roundworm, pinworm, leishmania, plasmodium, trypanosome, giardia

11

Define hemiparasite

a parasitic plant that derives some or all of its sustenance from another plant

12

Give an example of a hemiparasite

mistletoe attaches to another plant and absorbs its nutrients. spread by birds eating the fruit and pooping the seeds out

13

Define host

the organism in or on which the parasite lives

14

Define definitive host

the organism in which the parasite reaches sexual maturity

15

Give an example of definitive host

the mosquito for malaria, the cat for toxoplasma

16

Define intermediate host

the organism in which the parasite completes part of its life cycle. parasites usually undergo a morphological or physiological change in this host

17

Give an example of intermediate host

humans for malaria, mice for toxoplasma

18

Define reservoir host

alternate animal host from which the parasite can be transmitted to humans (zoonosis) or domestic animals

19

Give an example of a reservoir host

the rat for toxoplasma

20

Define zoonosis

a parasitic disease in which an animal is normally the host, but which also infects humans

21

Define accidental host

one that accidentally harbors an organism that is not usually parasitic in the particular species and cannot be transmitted. parasite usually finds an immunologically privileged site (ie. brain, eyes, testes, etc)

22

Give an example of an accidental host

humans and the pork tapeworm Taenia solium. causes human cysticercosis

23

Define vector

a host that plays an active role in the transmission of the parasite. can be a definitive or an intermediate host

24

Give an example of a vector

female Anopheles mosquito that transmits malaria

25

What are some characteristics of parasites?

usually smaller and more numerous than their host, may be some degree of genetic complementation, parasite is physiologically or metabolically dependent upon its host, reproductive potential of parasites exceeds that of their host

26

Why are many host-parasite interactions species-specific?

because of co-evolution

27

What are the steps to parasite infection?

1) encounter
2) entry/attachment
3) spread within body
4) multiplication
5) damage
6) outcome- either parasite or host wins, or they coexist

28

What are the main modes of parasite transmission?

skin, respiratory, gastrointestinal, urogenital
vector borne, blood transfusion, organ transplant

29

What are the two types of vector borne transmission?

external and internal transmission

30

Define harborage transmission

internal vector borne transmission where the pathogen does not undergo changes within vector (mechanical vector)

31

Define biologic transmission

internal vector borne transmission where the pathogen undergoes changes within the vector (biological vector)

32

Define infectivity

ability of the organism to establish a discrete, focal point of infection

33

Define invasiveness

ability of organism to spread to adjacent or other tissues

34

Define infection

a parasite growing and multiplying within or on a host, usually accompanied by an immune response

35

Define pathogenicity

ability of parasite to cause disease

36

Define virulence

degree of pathogenicity, the ability for the organism to invade, infect, grow and cause damage despite the host's defences. determine in part by pathogen's ability to survive outside the host

37

Define symbiosis

living together

38

What are the four types of symbiosis?

phoresis, commensalism, mutualism, and parasitism

39

Define phoresis

'to carry'. when one organism is mechanically carried on or in another species (host)

40

Give an example of phoresis

beetle with hitch-hiking mites, hermit crab carrying sea anemones, crab carrying a fire urchin

41

Define commensalism

involves one way benefit, but no harm is exerted in either direction. usually involve a feeding relationship but not metabolic independence

42

Give an example of commensalism

pilot fish attaches to shark and eats the debris from the shark's prey.
egrets sit on livestock and eat insects surrounding them
sea anemone protects clown fish, which has an extra mucous layer for protection from nematocyst discharge

43

Define mutualism

highly inter-dependent association, often to the extent where the two cannot survive without one another

44

Give an example of mutualism

flagellate protozoa live in termites and digest the wood for them.
Yucca plant is only pollinated by yucca moths, and yucca moth larvae can only eat the seeds of yucca plants

45

Define parasitism

intimate relationship between two organisms in which one lives on, off, or at the expense of the other (host)

46

Give an example of parasitism

canine heartworm, malaria