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Y1 - Microbio Exam 3 > 5_Helminthes 2 > Flashcards

5_Helminthes 2 Flashcards

1
Q

Nematodes (Round worms):

characteristics

A
  • cylindrical
  • structure
    • body wall composed of outer cuticle, thin hypodermis, and musculature
    • tubular intestine w/ excretory gland
  • sexual reproduction: testes & ovaries; copulation is necessary for fertilization
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2
Q

pathogenesis of Nematodes

A
  1. diseases are caused by direct damage from worm activity and immune rxn to them
  2. large worms can physically block the intestine
  3. Infxn is related to the # adn the infective stages encountered
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3
Q

how do humans respond to infxn by Nematodes?

A
  • children are more susceptible than adults
  • waning of immune competence w/ age increases infxn
  • Immunosuppressive therapies may inc. susceptibility
  • immune defense thru production of IgE and action of mast cells and eosinophils
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4
Q

what are the common nematodes to know?

A
  • Pinworm (Enterobius cermicularis)
  • Trichinella (Trichinella spiralis)
  • Toxocariasis (Toxocara canis, Toxocara cati)
  • Whipworm (Trichuris trichura)
  • Ascariasis (Ascaris lumbricoides)
  • Hookworm (Necator ameicanus, Ancylostoma duodenale)
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5
Q

lifecycle for Enterobius vermicularis (Pinworm)

A
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6
Q

life cycle of Trichinella spiralis

A
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7
Q

name 2 worm infxns that one can contract by eating undercooked pork?

A

Taenea (tapeworm) and Trichinellosis

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8
Q

which two species cause Toxocariasis,

and which animal causes it?

A
  • Toxocara canis from dogs
  • Toxocara cati from cats (less common)
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9
Q

Life cycle of:

Toxocara species

A
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10
Q

the eyes are affected by which worm infections?

A
  • Toxocariasis - granuloma, ocular larva migrans
  • Trichinella spiralis - swelling
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11
Q

Which worm can cause splinter hemorrhages of the fingernails , or a cough?

A

Trichinella spiralis worm movement

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12
Q

life cycle and transmission:

Trichuris trichiura

A
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13
Q

life cycle of:

Ascaris lumbricoides

A
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14
Q

which of the following nematode (round worms) infect w/in the GI tract only?

  1. Pinworms
  2. Whipworms
  3. Trichinellosis
  4. Ascariasis
A

Pinworms, and Whipworms

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15
Q

Where do adult Schistosoma mansoni reside and is it in a round worm?

A

Veins that drain the intestine

S. mansoni is a type of flatworm (*NOT a roundworm)

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16
Q

Hookworm infection:

causal agents,

how frequent?

transmission?

A
  • causal agents:
    • Necator americanus - predominates in the Americas (north, central, and south america) and australia
    • Acylostoma duodenale - occurs in the middle east , southern europe, and north america
  • 2nd most common human worm infection
  • transmssion: soil-transmitted helminth (STH) - often occur in areas where human feces are used as fertilizer, or where degacation onto soil happens
17
Q

Life cycle of Hook worm

A
18
Q

Hookworm:

presentation

A
  • infxn is not common in adults
  • cutaneous larva migrans - red, intensely pruruitic (itchy), very painful, creeping eruption, ambiguously known as “ground itch”
    • usually heals spontaneously over wks to months
    • scratched may allow a secondary bacterial infxn to develop
19
Q

High intensity Hookworm:

affects which groups?

which symptoms?

A
  • *High intensity hookworm infxns: occur in school-age children
  • Sxs: development of anemia & protein deficiency caused by blood loss @ site of intestinal attachment
    • When continuously infected by many worms, children have loss of iron and protein, can lead to retarded growth and mental development
20
Q

Zoonotic hookworms?

key characteristics

A
  • Common in puppies/kittens, esp in areas w/ wamrer climates
  • Causal agents: Ancylostoma braziliense, A. caninum, A. tubaeforme
  • Transmitted in dog & cat feces, w/ warm, moist conditions hatch into larvae after several days
    • larvae of dog hookworms –> can infect people
    • larvae penetrate skin while people walk barefoot, or w/ exposed skin contact w/ contaminated soil/sand
    • larvae –> cutaneous larval migrans –> which don’t usually develop into adult hookworms in people –> larvae will die in the skin after several weeks w/o developing any further
      *
21
Q

Strongyloidiasis:

  1. etiologic agent, hx
  2. transmission
A
  1. causal agent: Stronglyoides stercoralis –> described in French troops stationed in Vietnam during the late 19th century
  2. Transmission: thru exposed skin, e.g. barefeet
22
Q

Strongyloidiasis:

typical manifestation

A
  • Manifestation: most infected people remain asymptomatic/undiagnosed
  • Larva currens: intensely itchy creeping raised rash, also known as ground itch
    • Allergic response to migrating filariform larvae
    • Appears recurrently along the thighs and buttocks, the site of skin penetration & intradermal migration
    • May last hours to days but in autoinfxn cycles can recur over weeks, months, & years
  • Tracheal irritation & dry cough: as larvae migrate from the lungs up thru the trachea
  • GI disturbance: abdominal pain, intermittent diarrhea/constipation, fecal occult blood, massive colonic and gastric hemorrhage
23
Q

Strongyloidiasis:

more serious manifestation

A
  • More serious manifestations: larvae invades numerous organs
  • Severe life-threatening forms of disease (fatality approaches 90%)
  • Affects pts receiving high-dose corticosteroids for the tx of asthma or COPD, and in patients getting immunosuppressive drugs bc of transplants (due to impaired host immunity à accelerated autoinfxn & # of migrating larvae)
  • Pulmonary infiltrates, acute respiratory distress syndrome (ARDS), small bowel obstruction, & multisystem organ system, & rapid clinical decline
24
Q

Which of the helminths cause pneumonia by migration to the lung is a step of the life cycle?

  1. Ascaris lumbricoides
  2. Anclyostoma duodenale
  3. Trichinellaosis (Trichinella spiralis)
  4. Toxocariasis (Toxocara canis, Toxocara cati)
  5. Strongyloidiasis (Strongyloides steroiralis)
A

1, 2, and 5

  • Ascaris lumbricoides
  • Anclyostoma duodenale
  • Strongyloidiasis (Strongyloides steroiralis)
25
Q

Guinea worm disease:

life cycle

A
26
Q

Guinea worm:

causal agent,

epidemiology,

sxs,

complications

A
27
Q

Prevention and control of

Guinea worm disease

A
  • Safe water –> using water filters
  • Health education and community mobilization
    • teaching communities about the disease and how it’s spread
    • chemically killing worms in water
    • identifying infected person w/in 24 hours of worm emerging
    • person should receive proper tx and case management by local health provider
    • w/in 7 days of worm emerging, GWEP supervisor determines that above criteria has been met
28
Q

Which of the following worms enter orally and move outside of GI tract?

  1. Ascariasis
  2. Hookworm
  3. Strongyloides
  4. Guinea worm
A
  • Ascariasis
  • Guinea worm
29
Q

Lymphatic Filariasis - Elephantiasis

life cycle and transmission

A
30
Q

Lymphatic Filariasis-Elephantiasis:

causal agent,

epidemiology

transmission

A
31
Q

Lymphatic Filariasis-Elephantiasis:

symptoms,

prevention and control

A

Sxs: Lymphedema of limbs, hydrocoele, chyluria

  • Majority of pts are asymptomatic, but virtually all of them have subclinical lymphatic damage
  • As many as 40% have kidney damage, w/ proteinuria & hematuria
  • Recurrent acute attacks – extremely painful, accompanied by fever

Prevention/Control: take precaution when traveling to an area w/ lymphatic filariasis

  • Sleep in air-conditioned room or under mosquito net; wear long-sleeves & trousers
  • Use mosquito repellant on exposed skin between dusk and dawn
  • Global campaign to eliminate lymphatic filariasis –> annual mass tx, and controlling mosquito
32
Q

Round worms are not transmitted by insect bites:

TRUE/FALSE

A

False, can be via insect bites, but can also be transmitted thru soil

(e.g. Filariasis-Elephantiasis)

33
Q

Define: Neglected parasitic infections

What are the top 5?

A
  • NPI: relatively little attention has been devoted to surveillance, prevention, and/or tx
  • Incl:
    1. Chagas disease
    2. cysticercosis
    3. toxocariasis
    4. toxoplasmosis
    5. trichomoniasis
34
Q

Which of the following worms infect by skin penetration?

  • Schistosoma haematobium
  • Dracunuculus medinensis (GWD)
  • Anclyostoma duodenale (Hookworms)
  • Anclyostoma braziliense (Dog hookworm)
  • Stronglyoides steroralis
A
  • Schistosoma haematobium
  • Anclyostoma duodenale (Hookworms)
  • Anclyostoma braziliense (Dog hookworm)
  • Stronglyoides steroralis

(All except Dracunulus medinensis (GWD), which is transmitted by infected copepods in unfiltered water)

Y1 - Microbio Exam 3 (13 decks)

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