Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Plagues & Pandemics > Parasites > Flashcards

Parasites Flashcards

1
Q

What are the two types of parasites and their distinguishing characteristics?

A
  1. Protozoa, unicellular (intracellular or extracellular)

2. Helminths (worms), up to meters long

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is African trypanosomiasis caused by?

A

Trypanosoma brucei - motile, vibrating parasites in the blood of livestock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Is trypanosomiasis a zoonosis?

A

Yes, from cows/horses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How is trypanosomiasis spread?

A

Tsetse fly transmission to humans causing “sleeping sickness”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the immune response to trypanosomes?

A

If parasites live extracellularly in the bloodstream, the infection is normally controlled by antibodies that eliminate the parasites.

If the parasite is able to escape the antibodies, it can spread to the brain and cause severe disease symptoms.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is giardia?

A

Giardia infection is an intestinal infection marked by abdominal cramps, bloating, nausea and bouts of watery diarrhea. Giardia infection is caused by a microscopic parasite that is found worldwide, especially in areas with poor sanitation and unsafe water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Tell me about the giardia parasite.

A
  • Parasites attach to mucosal epithelium and can survive for weeks in the host.
  • Prophozoite form is replicating form in intestine.
  • Cyst form passed in feces.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the animal reservoir for giardia?

A

Beaver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is toxoplasmosis?

A

Zoonosis caused by Toxoplasma gondii parasite commonly found in contaminated food or rat feces.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is toxoplasmosis spread?

A

T. gondii forms cysts in muscle tissue and oocysts in fecal tissue. Oocysts in fecal tissue are ingested by mice or humans (smell) and form tissue cysts in muscle or nerve muscles. Ingesting undercooked meat from animals with cysts in tissue also spread the disease.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Tell me the prevalence in the United States, Canada, France, and Brazil.

A

US: 9-11%
Canada: 17%
France: 47%
Brazil: 50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a definitive host?

A

Hosts in which the adult form matures. This is usually host where sexual reproduction takes place.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is an intermediate host?

A

Those which may have larval forms or cysts form. For many parasites, the cyst form in the intermediate host must be eaten (and digested out of cyst) to pass onto a definitive host.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a dead-end host? What’s an example of one?

A

An intermediate host that does not allow transmission to a new definitive host. For example, a dead-end host could be tapeworm cysts in humans where the flesh is unlikely to be eaten by carnivores.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the definitive host, intermediate host, and dead of Toxoplasma gondii?

A

Intermediate: rat

Definitive: cat

Dead-end: human

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are is the most common infection worldwide?

A

Parasitic worms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Most worms do not cause great ___ but can result in ___ for infected individuals?

A

mortality, morbidity (disease effects)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why does helminth size matter in terms of immune response?

A

The large size of helminths (large enough to be seen with the naked eye) makes it difficult to eliminate by normal immune function. Worms are often “ignored” by the immune system rather than causing disease in attempts to eliminate the worms.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where can worms live?

A
  • Most extracellular worms live in the intestine.
  • Schistosoma worms are blood flukes that reside in blood vessels.
  • Guinea worms live in peripheral tissues.
  • Intestinal worms traffic through lungs or other tissues as part of life cycle.
  • Worms can be found in intracellular cyst form (which enhances transmission).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the most common worm infection in the United States?

A

Nematode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is pinworm?

A

An urban pathogen caused by the worm Enterobium vermicularis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Prevalence of pinworm infection in children can be as high as __%.

A

50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Is there an animal reservoir for pinworm?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How are pinworms spread?

A

Small segmented roundworms transmitted through fecal/oral route. People are infected by ingesting eggs from fingers, clothing, and other surfaces.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Adult pinworms can achieve what length?

A

1 cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the most common sites of outbreaks of pinworm?

A

Childcare centers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How can pinworm be diagnosed?

A

Itching and examining for eggs by tape test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is ascaris?

A

Large round worms that live in humans’ small intenstines (although another species infects pigs!).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

More than __ billion people are thought to be infected with ascaris at any given time.

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Adult female ascaris can reach up to __ cm long, whereas males are ____.

A

30, smaller

31
Q

Detail the ascaris lifecycle.

A

Ingested egg hatches in small intestine. → Larvae penetrate the intestine, travel through lymph and blood to liver, heart, and lungs. → Larvae mature in liver and then travel out capillaries into lungs where larvae are coughed up and swallowed to enter intestine (9 days after initial infection). → They mature over next 8-12 week into sexually mature adults.

32
Q

Ascaris is highly endemic in many ___ and ___ areas where as many as __% of some communities will be passing Ascari eggs.

A

tropical, subtropical, 85

33
Q

What is the primary preventive issue of Ascari?

A

Sanitary disposal of feces

34
Q

The majority of infections are people with low ___ ___ and are usually ___.

A

worm burden, asymptomatic

35
Q

Why are people with heavy worm burden still rarely diagnosed with Ascaris?

A

Because symptoms like stomach problems or pneumonitis are not specific to Ascaris

36
Q

What does definitive diagnosis of Ascaris require?

A

Finding eggs in stool

37
Q

What is the most life-threatening complication of Ascaris infection?

A

Blockage of intestine or bile ducts (with heavy worm burden)

38
Q

Only in extreme cases do adult Ascaris worms…

A

exit the nose, mouth, or anus.

39
Q

How is hookworm (a nematode) transmitted?

A

Contaminated feces or from contact with larval form in soil

40
Q

What do hookworms ingest for nutrition?

A

Red blood cells

41
Q

Hookworms hook onto ___ ___ with their “teeth.”

A

intestinal wall

42
Q

Describe the hookworm lifecycle.

A

Larval form in soil enter through unbroken skin → Travel to intestine to mature into an adults → Find mate and produce eggs to pass in feces

43
Q

Is trinchinella intracellular or extracellular?

A

Intracellular

44
Q

Trichinella causes what and how?

A

Trinchinosis, by making cysts in muscle which can be transmitted to humans when they eat undercooked pork

45
Q

Where to Trichinella live?

A

Intestine

46
Q

How long are adult Trichinella?

A

1-2 mm

47
Q

Detail the trichinella life cycle.

A

Ingestion of meat scraps or animal scraps by a pig → Ingestion of undercooked pork by a human → Larva released in small intestine → Larvae grow into adults → Larva deposited in mucosa → Encysted larva in striated muscle

48
Q

What is Filariasis?

A

A parasitic disease caused by an infection with roundworms of the Filarioidea type.

49
Q

For filarial worms, humans are what kind of host?

A

Definitive

50
Q

Are filarial worms a zoonosis?

A

No, it has a mosquito vector

51
Q

Detail the filarial worm lifecycle.

A

Mosquito takes blood meal and larvae enter skin → Worms become adults → Adults produce sheathed microfilariae that migrate into lymph and blood channels → Mosquito takes a blood meal and ingests microfilariae → Microfilariae shed sheaths, penetrate mosquito’s midgut and migrate to thoracic muscles → L1 larvae → L3 larvae → Migrate to head and mosquito’s proboscis where mosquito can then allow larvae to enter skin

52
Q

What do filarial worms cause?

A

Lymphatic filariasis, or elephantiasis

53
Q

Filarial worms are high on list of ___ ___ ___.

A

neglected tropical diseases

54
Q

How many are estimated to be infected by filarial worms?

A

120 million

55
Q

The Carter Center has provided targeted elimination with what? (2)

A
  1. Drugs donated by Merck and GlaxoSmith Kline

2. Insect treated bednets

56
Q

What is another word for “guinea worm”?

A

Dracunculiasis

57
Q

What causes guinea worm?

A

Ingestion of drinking water with infected small crustaceans (copepods)

58
Q

Female Guinea worm forms painful lesions up to __ year after infection.

A

1

59
Q

When exposed to water, the female releases ___ into water.

A

larvae

60
Q

Guinea worm extends its ___ through the skin.

A

Anterior end

61
Q

How do you remove guinea worm?

A

Gradual twisting

62
Q

What is the key to limit transmission of guinea worm?

A

Education

63
Q

Is there a vaccine or drug treatment to prevent guinea worm?

A

No

64
Q

What are cestodes?

A

Flat segmented worms, primarily intestinal dweeling tapeworms

65
Q

Why are cestodes true parasites?

A

They lack a mouth, alimentary tract, circulatory system, body cavity, and major metabolic pathways. These worms absorb their nutrient molecules through their body surface.

66
Q

Tell me about tapeworm anatomy. (3)

A
  1. The scolex is the anterior-most portion of the adult worm and is armed with large hooks that alternate with small ones.
  2. The base of the scolex forms a neck which contains germinal cells that give rise to proceeding segments.
  3. The neck is followed by a chain of flat, ribbon-like segments referred to as the proglottids.
67
Q

What do tapeworm infections cause?

A

Taeniasis

68
Q

What are the harmful effects of taeniasis?

A

Cysts in muscle or liver may lead to muscle aches or inflammation; cysts in the eye might lead to blindness; cysts in teh brain may lead to neurological damage

69
Q

What are trematodes?

A

Commonly known as flukes

70
Q

What is schistosome? How long do they live?

A

A trematode blood fluke. These worms can be extremely long-lived in hosts, usually 4 years but can live up to 20.

71
Q

How many people worldwide does schistosomiasis affect?

A

Over 200 million people

72
Q

Schistosomiasis is endemic to __ developing countries throughout the tropics.

A

76

73
Q

Detail the schistosome life cycle.

A

Eggs are released in urine or stool of infected individuals into fresh water where they hatch and infect the intermediate host, a freshwater snail. → After infection, asexual proliferation occurs in snail and thousands of new larval parasites (cercariae) emerge to swim and ultimately penetrate skin.

74
Q

How is the schistosome couple configured?

A

The female worm is inside of the canal of the male worm

Plagues & Pandemics (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions