Life Cycles Flashcards

1
Q

what can knowing the life cycle help with?

A

-diagnose disease & ID parasite
-predict what pathogenic changes may occur
-optimize treatment to improve control
-develop environmental control programs
-reduce cross-species (including zoonotic) infections

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2
Q

Define definitive (primary, principal, final) host

A

host in which the adult or sexually reproductive, stages of the parasite occur

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3
Q

Define intermediate (secondary) host

A

host required for parasite development but in which the parasite does not become sexually mature

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4
Q

Define paratenic (transport) host

A

host in which parasite does not undergo any required development but in which it remains alive & infective to another host

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5
Q

what is included in a direct life cycle?

A

definitive host and no intermediate host

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6
Q

define monoxenous parasite

A

parasites with direct life cycles

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7
Q

what types of parasites are monoxenous?

A

nematodes and protozoa

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8
Q

when might be the infective stage in a direct life cycle?

A

resting stage or active stage

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9
Q

what are the modes of transmission of a resting stage in the direct life cycle?

A

ingestion

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10
Q

what are the modes of transmission of the active stage in the direct life cycle?

A

ingestion, penetration of skin, direct contact

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11
Q

what are two parasites with direct life cycles?

A

Ascaris suum and Hyastrongylus rubidus

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12
Q

what is included in a indirect life cycle?

A

requires an intermediate host

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13
Q

what type of life cycles do heteroxenous parasites have?

A

indirect life cycle

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14
Q

what are some heteroxenous parasites?

A

trematodes, most tapeworms, and many parasitic nematodes, and protozoa

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15
Q

when might be the infective stage in an indirect life cycle?

A

resting stage
active stage

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16
Q

what are the modes of transmission in the resting stage of the indirect life cycle?

A

transmission via ingestion

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17
Q

what are the modes of transmission in the active stage of the indirect life cycle?

A

penetration of skin, via vector

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18
Q

what are two parasites with indirect lifecycles?

A

Spirurid nematode
Dirofilaria immitis

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19
Q

Are paratenic hosts required for completion of parasites life cycle?

A

Not required, facilitates transmission to definitive host

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20
Q

what is the paratenic host for Stephanurus dentatus (swine kidney worm)?

A

earthworm - carries infective larvae

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21
Q

what are the 4 modes of transmission with Stephanurus dentatus?

A

-ingestion of free infective larvae
-ingestion of earthworm (paratenic host) carrying infective larvae
-penetration of skin by infective larvae
-transplacental transmission

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22
Q

what ectoparasites serves as parasites and vectors?

A

arthropod ectoparasites

23
Q

what are the two main life cycles for ectoparasites?

A

-holometabolous (complete) metamorphosis
-hemimetabolous (incomplette, simple) metamorphosis

24
Q

Describe the holometabolous (complete) metamorphosis

A

egg -> larva -> pupa -> adult

25
Q

Describe the hemimetabolous (incomplete, simple) metamorphosis

A

egg -> larva -> nymph -> adult
egg -> nymph -> adult

26
Q

what type of metamorphosis has larval that is morphological different from the adult?

A

holometabolous (complete) metamorphosis

27
Q

what type of metamorphosis has larval that is morphological similar to the adult?

A

hemimetabolous (incomplete, simple) metamorphosis

28
Q

what type of metamorphosis do fleas and dipterans have?

A

holometabolous

29
Q

what type of metamorphosis do tick, mites, and lice have?

A

hemimetabolous

30
Q

what type of metamorphosis is this?

A

hemimetabolous

31
Q

what type of metamorphosis is this?

A

holometabolous

32
Q

what is the mode of transmission of Dirofilaria immitis

A

vectored by moquitoes

33
Q

what is the infective stage of Dirofilaria immitis

A

third-stage larva, L3

34
Q

How does Dirofilaria immitis get from the mosquito into the host?

A

L3 migrates through mosquito bite wound

35
Q

What is the predilection site of the adult for Dirofilaria immitis?

A

pulmonary arteries, right ventricle

36
Q

what is the route to the predilection site for Dirofilaria immitis?

A

venous circulation (from subcutis and abdominal/thoracic muscles)

37
Q

what is the mode of exit of Dirofilaria immitis?

A

blood ingested by mosquito

38
Q

what is the exiting/diagnostic stage of Dirofilaria immitis?

A

Microfilaria in blood

39
Q

where is A. suum located in the pig throughout its life?

A

larva in lung tissue
larva in large intestinal wall and liver (migrate up to lungs)
larva in small intestine (prepatent week 6-8)

40
Q

what pathogen might have caused this?

A

A. suum

41
Q

Define prepatent period

A

time between infection of a definitive host and the appearance of stage exiting host

42
Q

how is the prepatent period controlled with A. suum?

A

control through deworming

43
Q

what is this a technique for?

A

collection of soil or vegetation samples to locate the different stages of the parasite external to host

44
Q

what can locating the different stages of the parasite external to the host help with?

A

epidemiology, environmental assessment, and control

45
Q

what environmental conditions that contribute to promoting development/survival of stage?

A

temperature, humidity, shade, etc.

46
Q

How does knowing the time required for development of stages and longevity of stages help with for parasite external to the host?

A

epidemiology, control
ex. knowing what egg looks like that is infective vs non-infective

47
Q

what parasite mostly develops and reproduces in only 1 host species?

A

lice

48
Q

what parasite mostly develops and reproduces in more than 1 host species but are restricted to a genus or family of hosts?

A

most coccidia

49
Q

what is a parasite that develops and reproduces in more than 1 family or order of hosts?

A

Trichonstrongylus axei

50
Q

what are the definitive and intermediate hosts for Toxoplasma gondii - toxoplasmosis?

A

definitive hosts - felids
intermediate hosts - mammals and birds

51
Q

what are the definitive and intermediate hosts for Schistosoma japonicum - schistosomiasis?

A

definitive hosts - rodents, carnivora, ungulates, primates, and other mammals
intermediate hosts - snails in genus Oncomelania

52
Q

what are the definitive and intermediate hosts for Plasmodium reichenowi - malaria?

A

definitive hosts - mosquitoes in genus Anopheles
intermediate hosts - chimpanzees

53
Q

what are the two main lifecycles for endoparasites?

A

direct and indirect