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Flashcards in L8: Introduction to Parasites Deck (104):
1

Risk factors for parasitic disease? 7

1. Traveler to endemic zones
2. Raw food
3. Barefoot exposure to soil
4. Exposure to fresh water
5. Injections
6. Sexual activity
7. Immunocompromised

2

Vectors and intermediate hosts of parasites?
Disease for each

1. Mosquitos: Malaris, filariasis
2. Flies: Leishmaniasis, trypanosomiasis, onchocerciasis
3. Snail: Schitosomiasis
4. Kissing bugs: Chagas disease
5. Fish: Diphyllobothrium latum
6. Large animals

3

What can be a vector?

Insect

4

2 categories of parasites?

1. Protozoa: Single celled
2. Metazoa: Multi-celled

5

4 types of protozoa?

Amoebas
Flagellates
Ciliates
Sporozoans

6

2 categories of metazoa?

Nemathelminths
Platyhelminths

7

Another word for metazoa?

Helminth

8

Protozoans can be divided by location in body, what is this? (2)

1. Lumen dwelling: don't invade
2. Tissue dwelling: invade

9

3 types of metazoa? with common name

1. Nematode: Round worm
2. Cestodes: Flatworms or Tapeworms
3. Trematodes: Flukes

10

Are protozoa pro or euk?

Eukaryote

11

Protozoa are found where?

Free living in marine, fresh water and terrestrial habitats

12

How are protozoa helpful?

Essential decomposers and part of food chain.

13

Do protozoa have a cell wall?
Are they eukaryotes?
Do they have chloroplasts?
How do they move?

No
Yes
No
Specalized structures: cilia, flagella, pseudopodia

14

Two forms a protozoan can exist as?
Define each

1. Trophozoite: vegetative/feeding form
2. Cyst: resting form

15

What is the most common mode of protozoan reproduction?
Specifically what form?
Is this sexual or asexual?

Binary fission

Schizogony

Asexual

16

Is a protozoan has a definitive host, how does it reproduce?

Sexually

17

What is schizogony?

Many fissions in which the nucleus divided numerous times and then the cell produces numerous single-celled organisms

18

Mechanisms of entry of protozoa?

1. Ingestion
2. Sexual transmission
3. Arthopod vectors

19

Example of direct inoclulation of protozoa?

Malaria

20

Example of indirect inoculation of protozoa?

Chagas' disease

21

2 mechanisms of protozoan pathogenesis?

1. Tissue damage
2. Release of toxins from tissue and parasite

22

Amoebas move by what object?

Pseudopodia

23

How many nuclei in amoebas?

1-2

24

How do amoebas replicate?

Binary fission

25

How do amoebas ingest?

Endocytosis

26

What do amoebas form under adverse conditions?

Cysts

27

Old designation of amoebas?
New designation of amoebas?

1. Sarcodina
2. Amoebozoa

28

Flagellates old designation?

Mastigophora

29

How do flagellates move?

Flagella, 1 or more

30

How many nuclei do flagellates have?

1-2

31

How do flagellates reproduce?

Binary fission

32

What do flagellates form under adverse conditions?

Cysts

33

Are flagellates life cycles simple or complex?

Both.

34

Hemoflagellates have a complex life cycle of how many forms?

4, 1 of which is intracellular

35

Hemoflagellates are transferred by who?

Insect Vectors to trypansoma and leishmania

36

Trypanosoma can cause what diseases? 2

1. African sleeping sickness
2. Chagas' disease

37

Ciliates are known as what?

Ciliophora

38

Ciliates move how?

Cilia rotating

39

How many nuclei in ciliates?

1-2

40

How do ciliates replicate?

Binary fission

41

How do ciliates ingest nutrients?

Through cytosome
Excrete waste through anal pore.

42

Sporozoans are known as what?

Apicomplexans?

43

What type of parasite is sporozoans?

Intracellular parasites.

44

How do sporozoans move? (2)

1. Flagella
2. Pseudopodia

45

How many nuclei do sporozoans?

1 or multiple nuclei

46

Sporozoans have how many developmental stages?

Several

47

Are sporozoans only able to have one host?

No

48

Sporozoans use what type of reproduction?

Sexual: Fusion
Asexual: Fission

49

End product of sporozoans sexual reproduction is what?

Oocyst

50

What is difference between intermediate host and definitive host

Intermediate host: Larval forms, asexual
Definitive host: Adult forms, sexual

51

What are the health strategies against protozoan parasites?

1. Control presence in environment
2. Prevention of infection
3. Treatment of infection

52

Prevention of infection is through what? 3

1. Hygiene
2. Vector avoidance
3. Immunization

53

Helminths/Metazoa have what common characteristics?

1. Multicellular and complex
2. Rudimentary nervous systems
3. Outer covering of cuticle that is shed
4. Use sexual reproduction (although some are hermaphroditic)
5. Highly allergenic (Type 1)

54

Nematodes have what sexual identity?

Male and female

55

Nematodes in the GI system do what?

Ova passes out

56

Nematodes in circulatory must be what?

Be ingested by vector

57

Nematodes in other tissues must be what?

Ingested by predator

58

Cestodes have what sexual identity?

Hermaphroditic

59

Do cestodes/proglottids exit under their own power or disintegrate?

Both

60

Trematodes are usually what sexual identity?

Hermaphroditic

61

Difference between cestodes and trematodes in terms of fertilization?

Cestodes: Self fertilize
Trematodes: Cross-fertilize

62

Trematodes in GI system do what?

Ova exit in feces

63

Trematodes in circulatory do what?

Erode to lumen

64

Trematodes in pulmonary system do what?

Exit in sputum or feces

65

What is a definitive host?

Harbors adult worms and is site where sexual reproduction takes place

66

What is an intermediate host?

Harbors larval forms and asexual reproduction may take place.

67

Helminth entry into body is by what means?

Intermediate host: Ingestion of larvae in tissue
Fecal-oral: Ingestion of eggs or larvae from feces of infected host
Skin penetration: Larval forms burrow through the skin
Injection by blood-sucking insect

68

Two broad categories of helminths?

1. Nemalthelminths (Roundworms)
2. Platyhelminths: Flatworms

69

What is the group of roundworms called?

Nematodes

70

What are the two subdivisions of flatworms?

1. Cestodes: Tapeworms
2. Trematodes: Flukes

71

Nematode body?

Long, cylindrical, narrow

72

After hatching how do nematodes develop?

Molt through 1 or more larval stages

73

Which is larger in nematodes, males or females?

Females

74

Do nematodes have digestive tracts?

Some do

75

For transmission of nematodes, what can be the infectious unit?
Which passes easily?

Egg: Pinworm (easily passes)
Larva: Hookworm

76

How does a larval/hookworm act as infectious unit?

1. Penetrate bare skin, enter blood stream
2. Carried to lungs, and travel up trachea to esophagus
3. Kids swallow them into intestine and they lay eggs here
4. Poop out eggs
5. Ova hatch in soil into first larval stage. and molt into second

77

Should you pull tissue nematodes out?

No

78

Tissue nematodes larvae are released into what?

Bloodstream or Exterior of body and are taken up by insects or intermediate hosts

79

How are tissue nematodes acquired? 5

1. Larvae ingested by copepods
2. Drink copepods from bad water
3. Larval migrate through tissues and mature
4. Female adults go to subcutaneous tissue on extremities to release larva into water

80

Platyhelminths have what shape?

Flattened

81

Platyhelminths are of what sexual identity?

Hermaphroditic

82

Which platyhelminths HAVE a digestive tract?

Flukes do

83

What do platyhelminths use for attaching to tissues?

Tapeworms: Hooks
Tapeworms AND flukes: Suckers

84

Cestodes have what two main parts?

1. Strobila
2. Scolex

85

The strobila is made up of what?

1. Proglottids
2. Gravid proglottids

86

Proglottids have what fnction?

Reproductive: Wil twitch and then dissolve releasing egg

87

Gravid proglottids have what?

Eggs

88

In intestinal cestodes, humans are what host?

Definitive host: Infected by larvae. Adult worms live in humans

89

In tissue cestodes, humans are what host?

Intermediate host: Ingest eggs to get infected. Larvae live in tissues

90

What is beef tapeworms lifecycle?

1. Ova are ingested by cattle (intermediate host)
2. Larvae ingested by humans (definitive host)
3. Proglottids and eggs in intestine.
4. Ova are shed in human feces

91

How does the pork tapeworm's lifecycle compare to the beef tapeworms?

Same

92

What happens if humans ingest pork tapeworm ova?

Cysticercosis: Larvae encyst in tissue

93

Trematodes have what symmetry?
What shape?

Bilateral
Leaf-shaped

94

What do suckers do in trematodes?

1. Hold on
2. Suck fluid

95

What are the trematodes to worry about?

Blood flukes

96

Definitive hosts of trematodes/flukes?

Humans, livestock

97

Intermediate hosts of trematodes/flukes?

Snails

98

What is lifecycle of trematode/fluke? 5

1. Larvae burrow into snails
2. Larvae multiply asexually and released into water
3. Larvae form cyst in second intermediate host or water vegetation
4. Cysts or larvae infect vertebrae host, mature and lay eggs
5. Ova passed from vertebrae host to hatch inw ater

99

Health strategies for parasitic helminths?

1. Control presence in environment
2. Prevention of infection
3. Treatment of infection

100

What are the treatment challenges to parasites?

1. Diagnosing
2. Effective medications (penetration and resistance)
3. Toxicity of medication
4. Expense of medication
5. Elimination of pathogen

101

Adult arachnids have how many legs?

4 pairs

102

What are the most important arachnid vectors?

Ticks

103

Insects have how many legs?
How many body regions?

3 pairs of legs
3 body regions

104

3 entomology relationships in humans?

1. Parasitic (live on/in us) Mites, lice
2. Predatory (feed on us sometimes): Fleas, mosquitos, ticks, (great vectors)
3. Polluting: Houseflies spreading germs