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Flashcards in Final; Parasites Deck (86):
1

Parasitic diseases are among the most prevalent diseases where

in developing countries

2

Parasitic infection is distinct from what

parasitic disease

3

What is parasitic disease a consequence of

porlonged, repeated, or high burden infection; usually subacute or chronic, rarely fatal (although there are exceptions)

4

Many parasitic infections are what

zoonosis; agents that infect animals

5

Many human parasites require what to complete their life cycles

human and nonhuman hosts; humans are dead-end hosts

6

What are the two types of parasites

protozoa (single cell)
helminths (multi-cell)

7

Disease is a consequence if parasite what is too high

replication; only a small amount is required to initiate infection

8

These are motile via flagella, parasitic form don't have mito or golgi, most form cysts and are free living and solitary

mastiogophora

9

This caused an infection in Milwaukee via the drinking water

crytosporidum

10

These are mostly not motile, produce sporozoites which are important in transmission of infections, the entire group is parasitic

apicomplexa

11

These are multicellular animals including roundworms, and flatworms, and are extracelluar protected by a cuticle

helminths (worms)

12

In this type of host, the developmental stages take place out side of the host and in the host, the organism reaches maturity

definitive host

13

This type of host is required for replication

intermediate host

14

This is a non-infected asymptomatic carrier, not partaking in transmission

reservoir

15

Most helminths cause what in humans

chronic infections that are tolerated by the human host

16

This is NOT a consequence of parasitic replication

disease

17

This is due to the number of parasites that the host initially acquired from the environment

parasitic burden

18

How are parasitic infection resolved

not by most response, they spontaneously resolve when adult worm reaches senescence

19

What are the major groups of parasitic helminths

flatworms
roundworms (nematodes)

20

What are the subdivisions of flatworms

cestodes
trematodes

21

What are the majority of parasitic vectors

arthropods; involved in key parasitic life stages

22

Parasitic prevalence is dependent on what

local conditions favoring vector breeding

23

What can be examples of reservoirs

humans
animals
environment (soil contaminated with parasitized feces)

24

*How can the parasite gain entry

oral ingestion
penetration of the skin (unbroken)
arthropod0borne

25

*This type of parasitic entry involves ascariasis and amebiasis

oral ingestion

26

*This type of parasitic entry involves hookworms and schistosomes

penetration of the skin (unbroken)

27

*This type of parasitic entry involves bite wounds (malaria) and blood transfusions possibly

arthropod-borne

28

What is key to parasitic transmission

its dependent on parasitic life cycle and presence or absence of intermediate hosts; schistosomiasis required snails, they are not present in the US or Europe, therefore no schisto there

29

Disease manifestation of parasites is dependent on what

the size of the inoculum (and it varies for different parasites)
amoebiasis; large inoculum
crypto; few cysts

30

How are blood flukes able to evade the human antibody and cell mediated immune response

host plasma protein coasints

31

How are trypanosomes able to evade the human antibody and cell mediated immune response

surface antigen variation

32

How are leishmania able to evade the human antibody and cell mediated immune response

superoxide dismutase secretion

33

The life cycle of some parasites is determined by what

the species and tissue tropism
duffy factor antigen required for malaria and many black africans don't have it = resistance

34

These type of changes can induce stage-specific transitions

temperature; some parasites only like certain temperatures, dictating where they live

35

Clinical damage due to parasites may be due to what

tissue damage
effect of host response
- may occur years after initial infection

36

This disease is caused by a trypanosomiasis and is transmitted via the kissing bug and found only in the americas

chagas disease

37

What are the symptoms of chagas disease

skin lesion
swollen eyelid
chronic infections = irreversible damage to organs

38

Eradication of chagas disease is only successful when one or more of these treatments are employed

chemoprophylaxis; preventative drugs
immunization
field control measures

39

Why is it difficult to immunize against parasites

many parasites coat themselves in host antigens
some rearrange their surface antigens
different proteins are displayed at different life cycles

40

This is the most important blood cell parasitic disease

malaria; most important of protozoan diseases

41

How many of the 156 names plasmodium protozoa are known to infect humans

4

42

Infection and subsequent development of malaria is driven by what in the US

travel

43

What is the only reservoir for plasmodia that can infect humans

infected humans

44

How do plasmodia infected humans transmit malaria

imported to new regions
induced via blood transfusions etc.

45

How is plasmodium spread in humans

sporocytes enter via mosquito bite and travels to liver
leave liver as merozoites
multiply in live and RBCs

46

How does malaria induce damage

paroxysm; simultaneous lysis of many RBCs and release of large number of merozoites

47

What can genetically predispose someone to be resistant to malaria

duffy blood group
sickle cell anemia
heterozygous individuals are carries

48

This drug targets the parasites food vacuole where hemoglobin is degraded, killing the parasite, but now, many parasites are resistant

chloroquine

49

This destroys RBCs and is endemic in the US and is transmitted the same as lyme disease

babesia

50

What is the life cycle of babesia

merozoites injected under skin by tick
RBCs invaded
no liver intermediate stage
lyses RBCs
ticks feed on infected RBCs to keep cycle

51

This is a common infection in humans, but disease is rare and it survives in macrophages

toxoplamsa

52

How is toxoplasmosis transmitted

consumption of inadequate cooked meat or food contaminated with cat feces
cyst penetrates the intestinal all and enters the blood stream

53

What does toxoplasma affect

can cause miscarriage
affects the amygdala in rats
may be linked to schizophrenia in humans
humans are 3 times more likely to die in a car crash

54

These are small protozoans transmitted by sandflies (middle east) which are rare in NA and Europe and has reservoirs in rodents, dogs, other animals, and humans

leishmania

55

What is the life cycle of leishmania

promastigote (flagellated) binds to macrophage and converts to amastigote (no flagella)

56

This causes african sleeping sickness and is transmitted via the tsetse flie

trypanosoma brucei

57

What are the reservoirs for african sleeping sickness

east africa; wild game
west africa; humans and domestic animals

58

What illness is caused by trypanosomes (african sleeping sickness)

systemic and chronic in blood stream

59

How does trypanosomes escape host immune detection

changing the dominant surface antigen
can infect for months and years

60

What is significant about the intestinal and vaginal protozoa

its varied based upon motility and replication

61

This has worldwide zoonosis with highly resistant cysts and is transmitted via ingestion of water contaminated by feces from animal carriers

giardia lamblia

62

What are the symptoms of giardia lamblia

intestional protozoan
mild, persistant diarrhea
do not invade; inflammation

63

This is a common vaginal flagellate, can cause vaginitis, can be transmitted via sex

trichomonas vaginalis

64

This is an amoebiasis, causes destruction of host tissue (colon), transmitted via fecal-oral, and may humans carry non-pathogenic amoebas

entamoeba histolytica

65

Hows does entamoeba histolytic invade and cause damage

adheres to cell receptors containing digalactose residues and kills on contact via pore forming proteins

66

What is required to eradicate entamoeba histolytica

cell mediated immunity; circulating antibodies not important

67

This is spread via zoonosis often in rural areas but also person to person via crowded urban environments

cryptosporidium

68

How is cryptosporidium spread

infectious oocytes produced in intestine and spread to other animals
does not invade intestinal epithelial or disseminate

69

This the most frequent intestinal helminth infection (south US)

ascaris

70

These intestinal helminths are common in temperate and tropical areas and prevalent in small children and institutions

pinworms

71

These eggs do not require maturation outside the body and are transmitted via fecal-oral, hatch in SI cause peri-anal itching

enterobius

72

What is the life cycle of a pinworm

person swallows egg
eggs hatch in intestine
larve mature to adult in a month
mating
females deposit eggs in anus
anal scratching spreads eggs to others

73

These penetrate the skin as filariform larvae via soil contemned with stool

hookworms

74

What specific condition will lessen the chances of being infected via a hookworm

asthma

75

hookworms are able to reduce what

allergic reactions

76

How is the life cycle of the hookworm maintained

move from skin to heart then to lung then are either coughed or swallowed; can cause chronic anemia

77

These intestinal helminths perforate the intestinal wall producing septicemia and can reinfect the same host; especially in the immunocompromised

strongyloides stercoralis

78

These are long ribbon-like worms that can penetrate deep tissue and from infective cystic larvae and is acquired by eating raw or undercooked meat or fish

tapeworms

79

Who is the tapeworm life cycle

depended on humans and cattle, infection from eating feces or beef with larvae; all human create with consumption of undercooked/raw meat

80

Deep tissue infections of tapeworms produce what

severe diseases
cysticercosis
echinococcosis

81

With tissue and blood helminths what are the infections like

asymptomatic
encysted larva in striated/cardiac muscle
cysts calcify but worms viable for 30 years

82

How are tissue and blood helminths acquired

skin acquired
each species (of schisto) has unique geographic distribution via snail intermediate host

83

How is schisto spread in the body

cercariae released from snails
burrow in skin of people with infected water
travel to blood and via portal venous system to mature
move in male/female pairs to the small/large intestine to reproduce

84

What does schisto eggs induce

formation of granulomas that undergo fibrosis that can produce disease symptoms years later

85

This is "river blindness" via black flies, elephantiasis via mosquitoes, and is not within the US due to geographic factors

filariasis

86

Where do filariasis larvae live

in subcutaneous tissues