Brainscape's Knowledge GenomeTM

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


See full index

Human Parasitology > Nematodes - Soil Transmitted Helminths > Flashcards

Nematodes - Soil Transmitted Helminths Flashcards

1
Q

What are the 3 most important STH infections?

A
  1. Trichuris 2. Ascaris 3. Hookworms (unholy trinity)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

In which class is Trichuris trichiura found?

A

Enoplea

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

What is the common name of Trichuris trichiura?

A

whipworm

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

Why did Trichuris trichiura get its common name?

A

anterior end = slender & posterior end = thicker like a whip

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

How can the egg of Trichuris trichiura be recognized?

A

very thick shells & opercular knobs

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

What environmental conditions stimulate embryonation in Trichuris trichiura?

A

moisture, shade leads to L3

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

Does the egg hatch in the external environment in Trichuris trichiura?

A

no they hatch in small intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens when Trichuris trichiura gets into the host?

A

hatch in upper portions of SI & burrow into cells of intestinal villi where they mature

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

Where does Trichuris trichiura molt?

A

cells of the intestinal villi

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

Where do adult Trichuris trichiura worms live?

A

colon submucosa

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

How can male and female Trichuris trichiura worms be identified?

A

male has coiled posterior end

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

How do Trichuris trichiura worms cause hemorrhage and anemia?

A

~0.005mL blood/worm per day lost in stool. infection of 200 worms in a child -> increases daily iron needs by 4.25mg/day -> iron deficiency

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

How does Trichuris trichiura cause colitis?

A

inflammation of colon

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

What is TDS?

A

trichuris dysentery syndrome: severe diarrhea

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

What can happen if pertistalsis is overstimulated?

A

rectal prolapse

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

What types of systemic effects can occur as a result of infection with Trichuris?

A
  1. stunted growth 2. impared cognitive function 3. finger & toe clubbing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is infection with Trichuris trichiura diagnosed?

A

eggs in feces

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

How is infection with Trichuris trichiura treated?

A

mebendazole & albendazole

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

Who is most likely to be infected with Trichuris?

A

children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where in the world is Trichuris trichiura infection found?

A

tropical climates (south east USA)

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

What conditions increase the chance that Trichuris trichiura is present?

A
  1. warm climate 2. rainfall & humidity 3. moisture retaining soil 4. shade
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

In which class is Ascaris lumbricoides found?

A

Chromadorea

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

What is the origin of Ascaris lumbricoides’ egg’s mammillated covering?

A

proteinaceous layer (outermost) from uterine wall

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

Why is Ascaris lumbricoides’ egg golden brown?

A

absorbs host bile

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

Where are ascarosides found and what is their function?

A

sugar bound to non sugar by glycosidic bond makes eggshell impermeable to H2O soluble substances

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

What is the size of adult Ascaris lumbricoides males and females?

A

males: 30cmx3mm females: 35cmx5mm

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

How many lips do Ascaris lumbricoides have?

A

3

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

What stage of Ascaris lumbricoides is ingested by the human?

A

infective egg

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

Where does Ascaris lumbricoides molt inside the host?

A

2x in lungs and once in small intestine

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

Where is Ascaris hemoglobin found?

A

perieuteric - in fluid surrounding parasite intestine hemolymph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How many subunits are in a Ascaris Hb molecules

A

8 identical subunits & 16 hemes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How tightly does Ascaris Hb bind to O2 compared to human Hb?

A

25,000x greater affinity for O2 than human Hb. mammals have millisec off rate vs. ascaris taken several minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Describe the hypothesis which explains the affinity of Ascaris Hb to oxygen.

A

steral biosynthesis hypothesis: seteral - lipid is needed for worms egg production and lots of O2 is needed for this. intestine has a low O2 so it is important the Hb retains O2 in Ascaris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are the 3 phases of Ascaris pathology?

A
  1. migration 2. pulmonary 3. intestinal (adults)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

When would you expect to observe Loeffler’s syndrome?

A

pulmonary stage of Ascaris pathology: increase in eosinophils in lungs responding to protein on larval surface causes cough, wheezing, and chest pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Where do adult Ascaris worms wander?

A

into pancreas or bile duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How is infection with Ascaris diagnosed?

A

eggs in feces

38
Q

How is infection with Ascaris treated?

A

albendenazole and mebendenazole, PZQ, piperzine

39
Q

Where do Ascaris infections occur most frequently?

A

warmer climates/poor sanitation in children (“backyard infection)

40
Q

How can infection of Ascaris be controlled?

A
  1. drug treatment 2. sanitation 3. no night soil 4. education
41
Q

In which class are the hookworms found?

A

Secerneutea

42
Q

How is the infection transmitted to the human host in hookworms?

A

skin penetration

43
Q

Is there an IH in the hookworm life cycle?

A

no

44
Q

How did hookworms get their common name?

A

skin penetration by larva

45
Q

Do hookworms have a buccal cavity?

A

yes has teeth or cutting plates

46
Q

What does the male hookworm do with the bursa?

A

holds onto female during mating

47
Q

What conditions stimulate the hookworm egg to embryonate?

A

warm, moist, shady

48
Q

Do hookworm eggs have a thick eggshell?

A

no: oval & very thin shell

49
Q

Where do the hookworm L1 and L2 stages live and what do they do?

A

soil, feed on fecal material & grow & molt

50
Q

Does the hookworm L3 feed?

A

no: transmission stage & lives in upper few cm of soil

51
Q

What do hookworm L3s do when the soil is dry? When the soil is wet?

A

dry: move down into soil vs. wet: move up in soil

52
Q

What are the 2 species of hookworms which most commonly infect humans? Compare distribution & buccal cavity morphology

A
  1. Necater americanus 2. Ancylostoma ducdenale
53
Q

What is the distribution of Necater americanus & buccal cavity morphology?

A

Southeast USA. anterior has 4 cutting plates & posterior has 4 teeth

54
Q

What is the distribution of Ancylostoma ducdenale & buccal cavity morphology?

A

Europe, Asia, Africa. anterior has 2 cutting plates, each plate has 2 teeth

55
Q

What are the 3 phases of hookworm infection?

A
  1. invasion 2. migration 3. intestinal
56
Q

What is ground itch?

A

local rash & irritation due to inflammatory rxn to bacteria

57
Q

Where is the principal site of damage during the migration phase for hookworms?

A

lungs: L3 break out of capillaries in alveoli causes coughing, pneumonia

58
Q

Why is the intestinal phase of hookworm infection the most serious?

A

adult worms in SI w/ cutting plates/teeth are burrowing into intestinal mucosa

59
Q

How do hookworms maintain blood flow?

A

secrete salivary secretion w/ anticoagulants

60
Q

What is the food resource of hookworms?

A

blood

61
Q

What is hemoglobinolysis?

A

worms digest Hb

62
Q

What enzymes are involved in hemoglobin digestion by hookworms?

A
  1. hemolysin 2. aspartic proteases & cystine proteases 3. metalloproteases 4. exopeptidases
63
Q

What is cutaneous larva migrans and by what species is it most commonly caused?

A

skin disease in humans caused by nonhuman hookworms that wander in the skin most commonly caused by Ancylostoma brazilense & A. caninum (cat & dog hookworms)

64
Q

What are the goals of Children without Worms program?

A

donate to national STH control programs

65
Q

What is MDA?

A

mass drug administrations (albendenazole & mebendazole)

66
Q

What is WASH?

A
  1. WAter (increase access to water for personal hygine & environmental sanitation) 2. Sanitation (reduce open defecation & latrines) 3. Hygine (hand & face washing, shoes)
67
Q

Compare autoinfection, homogonic cycle, and heterogonic cycle.

A

autoinfection: life cycle of a parasite in one host vs. homogonic cycle: has a free living stage vs. heterogonic cycle: organism that has a parasitic stage

68
Q

Under what conditions is heterogonic cycle most likely to occur?

A

unfavorable conditions

69
Q

What sex of Strongyloides stercoralis is found inside the host ?

A

females

70
Q

What does protandrous mean?

A

male reproductive organs come to maturity before the female

71
Q

What is common name of infection with S. stercoralis?

A

threadworm infections

72
Q

What are the 3 phases of pathology S. stercoralis pathology?

A
  1. cutaneous: ground itch 2. pulmonary: cough, tracheal irritation 3. intestinal: nausea, pain
73
Q

How is immune status related to hyperinfection syndrome?

A

impaired host immunity leads to accelerated autoinfection with overwhelming # of migratory larvae & adults in SI -> disseminated & strangyloidiasis: larvae invade organs -> death rate approaches 90%

74
Q

What can occur during disseminated strongyloidiasis?

A

larvae invade organs

75
Q

How is strongyloidiasis diagnosed?

A

ELISA

76
Q

How is S. stercoralis infection treated?

A

invermechin

77
Q

What populations are most at risk for S. stercoralis infection?

A

people who come in contact with warm, moist soil

78
Q

In which class is Enterobius vermicularis found?

A

secerneutea

79
Q

How did Enterobius vermicularis get its common name?

A

pinworm because it looks like a pin

80
Q

Is Enterobius vermicularis common? Has it been around for a long time?

A

yes: oldest and most common parasite in the New World

81
Q

What are the alae in Enterobius vermicularis?

A

thickenings of cuticle at anterior end

82
Q

How can you differentiate male and female Enterobius vermicularis worms?

A

female: posterior end very pointed vs. male: coiled posterior end

83
Q

Where do adult Enterobius vermicularis worms live?

A

secum and colon

84
Q

What stage of Enterobius vermicularis is ingested by the host?

A

infective eggs

85
Q

What is retroinfection?

A

eggs hatch in perianal area and L1s go back into intestine

86
Q

What is autoinfection?

A

host ingests eggs produced by worms in host’s body

87
Q

What pathology can result from infection with a large number of Enterobius vermicularis worms?

A

1.damage w/i intestine or around anus -> inflammation & bacterial infection 2. irritability 3. sleeplessness

88
Q

How is Enterobius vermicularis infection diagnosed?

A

scotch tape test

89
Q

What is the characteristic morphology of Enterobius vermicularis eggs?

A

one side is flat the other is rounded

90
Q

How is Enterobius vermicularis infection treated?

A

pyrautel

91
Q

Who should be treated if one person in the household is infected with Enterobius vermicularis? Why?

A

everyone bc infection is passed very easily

92
Q

What age group is Enterobius vermicularis infection most prevalent? Why?

A

children because there is a lot of contamination at day care

Human Parasitology (22 decks)

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