Parasites Flashcards

1
Q

What are protozoa?

A

Unicellular eukaryotes.

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2
Q

What is the cyst form of a protozoa?

A

Tough protective layer outside plasma membrane to protect against inhospitable environments.

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3
Q

What is the trophozoite form of a protozoa?

A

Growing form without a cyst wall.

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4
Q

What do we call the cyst form of a protozoa when it is a sexually reproducing organism?

A

Oocyst.

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5
Q

What is a characteristic symptom of Entamoeba histolytica?

A

Bloody diarrhea.

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6
Q

Does Entamoeba histolytica have a cyst form?

A

Yes.

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7
Q

The cyst/oocyst form of some parasites have a high degree of ________ resistance. Why is this especially problematic?

A

chlorine.

Our drinking water is usually treated with chlorine so they can exist comfortably in tap water.

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8
Q

Why can some parasites (Entamoeba histolytica, Giardia lamblia, Trichomonas vaginalis) be treated with metronidazole (an antibiotic)?

A

They are anaerobic parasites and the antibiotic targets anaerobic organisms.

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9
Q

What is a major sign of giadiasis (“Beaver fever”, caused by Giardia lamblia)?

A

Flatulence (gas) & diarrhea.

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10
Q

Does Giardia lamblia have a cyst form?

A

Yes.

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11
Q

Giardia lambia can be found in _____ because it has a ________.

A

water, flagella.

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12
Q

Does Trichomonas vaginalis (“trich”) have a cyst form?

A

No.

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13
Q

How is Trichomonas vaginalis spread?

A

Person-to-person via sexual transmission.

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14
Q

Where can Trichomonas vaginalis be found?

A

In the vagina & male urethra.

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15
Q

What are symptoms of Trichomonas vaginalis?

A

Itching & inflammation of tissues.

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16
Q

Acanthamoeba are trophozoites in _____ and cysts in ____.

A

water, dust.

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17
Q

Acanthamoeba are often found in the ___, which is why they are often problematic for those who wear ______ ______.

A

eye, contact lenses.

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18
Q

What is the outcome of Acanthamoeba infection?

A

Vision or eye loss.

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19
Q

Cryptosporidium parvum reproduces ________, which means they have _______.

A

sexually, oocysts.

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20
Q

Where do we usually find Cytosporidium parvum?

A

Animals like cows, rats, dogs & cats.

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21
Q

How do people usually get Cytosporidium parvum?

A

Water contaminated with animal manure.

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22
Q

What is a characteristic symptom of infection by Cytosporidium parvum?

A

Chronic diarrhea.

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23
Q

Toxoplasma gondii is _________ reproducing, so they have an ______ form.

A

sexually, oocyst.

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24
Q

Where is Toxoplasma gondii usually found?

A

Cat feces.

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25
Q

How is Toxoplasma gondii usually acquired?

A

Eating uncooked meat with tissue cysts or contact with cat feces.

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26
Q

Which demographic of people is Toxoplasma gondii particularly dangerous for?

A

Pregnant women.

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27
Q

Trypanosoma are _____ parasites.

A

blood

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28
Q

How is Trypanosoma usually transmitted?

A

vectors - bugs.

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29
Q

What are the two types of Trypanosoma we need to know and to where are they endemic?

A

T. brucei gambienese/rhodesience in Africa.

T. cruzi in South America.

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30
Q

What is the vector of transmission for Leishmania?

A

The sandfly.

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31
Q

Describe the 3 different degrees of infection for Leishmania from most to least serious?

A

Visceral: affects internal organs.
Mucocutaneous: parasite eats cartilage.
Cutaneous: sores on skin.

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32
Q

How does Leishmania grow & avoid destruction by macrophages?

A

They live & develop in macrophages and affect the macrophage’s killing ability so they can grow safely.

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33
Q

Plasmodium species is the cause of _______.

A

malaria.

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34
Q

What are the 5 types of Plasmodium that we have to know?

A
  1. P. falciparum.
  2. P. malariae.
  3. P. ovale.
  4. P. vivax.
  5. P. knowlesii (new).
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35
Q

What is the most dangerous type of Plasmodium and why?

A

P. falciparum because it targets all ages of RBCs.

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36
Q

Why are symptoms of infection by P. falciparum?

A
Fevers & chills (toxic breakdown products of RBC destruction).
Cerebral malaria (sequestration of parasites & RBCs blocking blood vessels & causing organ death).
Anemia (due to lysis of RBCs).
Kidney failure (too many Hemoglobin breakdown products).
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37
Q

Where is the focus of infection for Plasmodium?

A

The liver.

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38
Q

When do we take blood to test for Plasmodium?

A

Fever - highest chance of finding it at that time.

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39
Q

What are metazoa?

A

Multicellular organisms (helminths)

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40
Q

What are the 3 major groups of worms causing human infection?

A

Nematodes, trematodes & cestodes.

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41
Q

What are 2 characteristics of nematodes?

A

Round, have a complete digestive system.

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42
Q

What are the 2 categories of nematodes & nematode infection?

A

Eggs as the infective stage.

Larva as the infective stage.

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43
Q

Enterobius vermicularis is also known as _______.

A

Pinworm.

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44
Q

Pinworm has ____ as the infectious stage.

A

eggs.

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45
Q

Where do pinworms live?

A

Large intestine.

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46
Q

Where & when do female pinworms go to lay eggs?

A

The external skin of the anus at night.

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47
Q

Which demographic is pinworm most common & most infectious in?

A

Kids.

48
Q

How are pinworm eggs transmitted?

A

Direct contact with eggs or ingestion of eggs stirred up in dust.

49
Q

Where can Ascaris lumbricoides usually be found?

A

Small intestine of pigs, cows, horses.

50
Q

Ascaris lumbricoides has ____ as the infectious stage.

A

eggs.

51
Q

What is the most common way for humans to get Ascaris lumbricoides?

A

Ingestion of eggs through unwashed or untreated foods (ex: vegetables fertilized with animal manure).

52
Q

Where do Ascaris lumbricoides eggs hatch and where do they go from there?

A

Hatch and become larvae in intestine → lungs → trachea → nose or mouth (children) OR back to intestine (adults).

53
Q

Why can Ascaris lumbricoides exit through the nose/mouth of children but not adults?

A

Children lack a well-defined swallowing reflex so the worms have no way of being swallowed down into the stomach.

54
Q

Adult Ascaris lumbricoides are ________ - they have distinct _____.

A

dioecious, sexes.

55
Q

How do we diagnose Ascaris lumbricoides infection?

A

Examining feces for eggs.

56
Q

Hookworms have ______ as the infectious stage.

A

larva

57
Q

Where do hookworms enter into the body and where do they go from there?

A

enter through intact skin of bare feet → lymphatic system → circulatory system → lungs → coughed up & swallowed down to small intestine, where they attach by hooks on the scolex (head)

58
Q

Hookworms suck _____, causing ______.

A

blood, anemia.

59
Q

Hookworms are only found in ____ climates.

A

warm

60
Q

Anisakis have _____ as the infectious stage.

A

larva

61
Q

Where can Anisakis usually be found?

A

Fish.

62
Q

How do humans usually get Anisakis?

A

Ingesting low-quality, raw fish.

63
Q

Trichinella spiralis has _____ as the infectious stage.

A

larva

64
Q

How do humans usually get Trichinella spiralis?

A

Ingesting encysted larvae in undercooked pork, boar, bear & walrus.

65
Q

What is a characteristic symptom of Trichinella spiralis?

A

Muscle weakness.

66
Q

Blood nematodes have _____ as the infectious stage.

A

larva

67
Q

What are the two notable blood nematodes infections?

A

Elephantiasis (lymphatic filariasis) & river blindness (onchoceriasis).

68
Q

Where are blood nematodes prevalent?

A

Africa, Asia, tropical Latin America.

69
Q

How are blood nematodes commonly transmitted?

A

Mosquitoes.

70
Q

Trematodes are ____-shaped & much _______ than nematodes.

A

leaf, smaller.

71
Q

What is the most prevalent type of trematode?

A

Schistosoma.

72
Q

How do Schistosoma adults hide from the immune system?

A

They have a protein coat stolen from the host.

73
Q

Where do Schistosoma worms reside inside the body?

A

The venous plexus of the bladder or the intestine.

74
Q

Where are ectoparasites found?

A

On skin

75
Q

What are the 2 types of ectoparasites?

A

Sarcoptes scabei and lice

76
Q

Secondary infections for lice occur when:

A

Lice feces are crushed into wounds

77
Q

What parts of the body does sarcoptes scabei infect?

A

Finger webs, elbows, armpits, breasts, groin and buttocks

78
Q

Describe sarcoptes scabei

A

Mites burrow into skin, feed, mate, and lay eggs

79
Q

What are the usual hosts of sarcoptes mites?

A

Not humans, animals (ie. dogs)

80
Q

What is the most dangerous type of tapeworm and why?

A

Pork tapeworm (Taenia solium): person-to-person transmission & can cause damage to nervous system.

81
Q

Lice penetrate the skin to:

A

Suck blood

82
Q

Female lice glue eggs to ____ ____ which hatch in - days

A

hair shaft, 5-10

83
Q

Secondary infections for lice occur when:

A

Lice feces are crushed into wounds

84
Q

The lifespan of sarcoptes scabei is:

A

30 days

85
Q

What are the 3 types of Schistosoma we need to know?

A

S. haematobium.
S. japonicum.
S. mansoni.

86
Q

Cestodes are _________ on their host for nutrients because they don’t have a ________ ______.

A

dependent, digestive system.

87
Q

The body of a cestode consists of segments called __________ which contain male and female ___________ ______.

A

proglottids, reproductive organs.

88
Q

Cestodes are also known as __________.

A

tapeworms.

89
Q

How do humans get tapeworm?

A

Eating inadequately cooked contaminated beef, pork or fish.

90
Q

What are the 2 diseases that tapeworm can cause?

A

Intestinal infection or deep tissue infection.

91
Q

What is the most dangerous type of tapeworm and why?

A

Pork tapeworm (person-to-person infection & can cause cysts in the brain).

92
Q

What is the least dangerous type of tapeworm?

A

Beef tapeworm (Taenia saginata).

93
Q

When we eat undercooked beef, we are ingesting beef tapeworm ______.

A

larvae

94
Q

Where do beef tapeworms mature in the human body?

A

The intestine.

95
Q

Humans are considered ____ _____ for dog tapeworm.

A

Dead hosts.

96
Q

What are the 2 modes of infection for pork tapeworm?

A

Eggs and larva.

97
Q

What is the vector for Babesia microti?

A

Ticks (Ixodes sp.)

98
Q

Is Babesia microti a protozoal or metazoal infection?

A

Protozoal.

99
Q

Where is Babesia microti commonly found?

A

Northeastern US.

100
Q

What kind of human body cells does Babesia microti replicate in?

A

RBCs.

101
Q

What does Babesia microti cause?

A

Hemolysis & anemia.

102
Q

How severe is Babesia microti infection considered in most people?

A

Mild to moderate.

103
Q

How is the Dracunculia species (Guinea worm) transmitted?

A

Fecal-oral.

104
Q

Where does the Guinea worm go in the body?

A

They penetrate the intestines & travel in the subcutaneous tissue.

105
Q

How do Guinea worms exit the body?

A

They cause a blister, which erupts and allows the worm to emerge.

106
Q

What happens when the Guinea worm senses water?

A

They release their larvae into the water.

107
Q

How could you treat someone with Guinea worm?

A

Slowly pull the worm out 1 inch per day so it doesn’t break & cause inflammation.

108
Q

Trichuris trichuria (whipworm) usually infects which demographic of people?

A

Children.

109
Q

Whipworm is usually found in ________/__________ countries & climates.

A

tropical/subtropical.

110
Q

Whipworm is usually associated with ___ feces.

A

rat.

111
Q

Whipworm is relatively benign, meaning those infected are usually ____________.

A

asymptomatic.

112
Q

Hymenolypsis nana is the most ______ tapeworm globally.

A

common.

113
Q

Hymenolypsis nana is usually found in ________ areas & climates.

A

tropical.

114
Q

Hymenolypsis nana doesn’t need an “intermediate host”, which means it can:

A

autoinfect a human.

115
Q

Those infected with Hymenolypsis nana often exhibit ___ symptoms.

A

few.

116
Q

How is Hymenolypsis nana transmitted?

A

Fecal-oral: ingestion of eggs.

117
Q

Hymenolypsis nana can cause tissue damage, leading to symptoms of:

A

enteritis (inflammation of small intestine), diarrhea, cramps.