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Parasitology > Chapter 12 > Flashcards

Chapter 12 Flashcards

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1
Q

Why are nematodes important

A

they are very abundant, probably more than arthropods, 1/4 of the world suffers from infection, parasitize humans, animals and plants, destroy 10% of all crops

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2
Q

What is the outer layer/skin of nematodes called, what is it make of is it stronger or weaker than platyhelminth outer layer

A

cuticle, collagen, much stronger

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3
Q

What happens if you put a platyhelminth in broth, and nematodes?

A

platyhelminth- changes size due to absorption

nematode-no absorption

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4
Q

What are the parts of nervous systems do nematodes have

A

nerve ring on small ganglia in pharynx

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5
Q

Are nematodes coelomates or pseudocoelomates

A

pseudocoelomates meaning it has no true body cavity/coelom

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6
Q

What kind of muscles do nematodes have, what neurotransmitter do they use for contraction

A

excitatory-acetylcholine-contraction
inhibitory- aminobutyric acid-release
sodium/potassium channels

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7
Q

What drugs are best against nematodes and why, what other creatures do they work against

A

ivermectim-blocks channels and causes tetani in nematodes and arthropods

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8
Q

What kind of sensory organs do nematodes have

A

amphids- chemosensory organs, on each side of the head, used to sense and release sex pheromones
phasmids-for touch and sensing light and dark, used for orientation

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9
Q

What kind of guts do nematodes have, name their parts

A

psuedocoelom

mouth, buccal cavity, pharynx, intestine, rectum, anus, males have cloaca

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10
Q

Explain what a cloaca is

A

a common urogenital opening, the rectum and the vas differens both open into this cavity

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11
Q

Describe the characteristics of nematode intestines

A

one cell thick, no muscle coating surrounding it, pseudocoelomate, food is moved by body movement

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12
Q

what kind of osmoregulatory abilities do nematodes have

A

free living forms are osmoconformers
parasitic form is more limited
excretory products stored in pseudocoelom and become isotonic with surroundings.

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13
Q

What does a pseudocoelomate lack that an acoelomate has

A

inner mesoderm-the parenchyma

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14
Q

How are free living nemotodes different from parasitic nematodes

A

free living-very small usually, no buccal cavity, no bursa

parasitic-can get up to 10m long, has a buccal cavity, might have a bursa

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15
Q

Explain what the buccal cavity does

A

attach to the villi of SI, some have teeth to rasp off mucosa
blood feeding nematodes have pharyngeal glands that produce anti-coagulants to help blood flow

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16
Q

Explain what the bursa is

A

preset in male strongyloide nematodes, is around the cloaca, wraps around female, increases efficiency of fertilization

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17
Q

What are the characteristics of nematode life cycles

A 
They all have 4 larval stages and 4 molts
egg
Larvae 1- rhabdiform
molt 1 
larvae 2 
molt 2 
Larvae 3-filariform 
molt 3 
Larvae 4 
molt 4 
adult
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18
Q

When is the best time to kill a nematode (what stages)

A

L1, L2 or L3 because you can stop the molting process by using growth regulators, very hard to kill adults

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19
Q

What marks the nematode’s adulthood

A

mating

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20
Q

What makes the larvae stages different

A

mouthparts and habitats change with each form

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21
Q

What makes the larvae stages different

A

mouthparts and habitats change with each form

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22
Q

What does molting mean for nematodes

A

shedding of the cuticle and secretion of a new one

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23
Q

How are nematode juveniles and adults different

A

juveniles are smaller and have no gonads
usually have a different diet
adults no longer molt

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24
Q

What is the important characteristic of the third larval stage of nematodes

A

often the resting or resistant stage before reaching adulthood

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25
What kind of sexes are nematodes? what type of sperm do they have?
always separate sexes, Males are smaller and have copulatory spicules, ameboid sperm
26
At what life stage are nematodes usually infective?
L3 stage, non feeding resistant stage
27
How is nematode egg production different to digeneans
no asexual reproduction so females are egg factories- 20K to 200K eggs/day
28
What parasite causes pinworms, what is the household way to test for it
enterobius vermicularis, scotch tape test
29
What are the characteristics of order strongylida nematoes
really big, usually infect domestic animals/ sometimes humans
30
What parasite causes hookworms
Necator americanus and Ancylostoma duodenale
31
Where are hookworms found in the world? in what environments
worldwide, moist, warm climate
32
What clinical issues do hookworms cause
iron deficiency due to anemia, cardiac complications, gastrointestinal and nutritional issues, ground itch, respiratory complications if pulmonary migration occurs
33
What parasite causes ground itch, explain what causes it
hookworms, local skin infection during penetration of filariform L3
34
What hosts do heomonchus contortus infect
grass eating animals like cattle and sheep
35
How do people often get hookworms?
by being barefoot, eggs are in human feces
36
How are hookworms IDed in the lab
eggs in stool under microscope
37
What are the characteristics of order Ascaris lumbricoides
largest nematode to parasitize human intestines- up to 35cm long
38
Where in the human body are ascaris lumbricoides found
adult in lumen of SI eggs in feces or swallowed larvae in intestinal mucosa larvae mature in lungs, alveolar walls, go up bronchial trees, to throat, swallowed again, get to small intestine, become adult worms
39
What are the ideal environmental characteristics for ascaris lumbricoides eggs, how long does it take for eggs to embryonate
moist, warm, shaded soil, fertile eggs become infective after 18+ days
40
How long do ascaris lumbricoides adult worms live
1-2 years
41
What clinical symptoms does ascaris lumbricoides cause
stunted growth, abdominal pain, intestinal obstruction, pulmonary symptoms, worms might leave mouth (holy shit ew)
42
How are ascaris lumbricoides IDed in the lab
eggs in stool under microscope
43
What animals do Baylisacaris procyonis parasitize?
racoon roundworms, eggs can get eaten by mice, squirrels, beavers and humans
44
How does Baylisascaris procyonis cause pathology in animals/humans, what name do these hosts have
``` paratenic hosts (small mammals and birds) larvae penetrate gut and migrate to tissues where they encyst, infect visceral organs, CNS and or eyes causing ocular larval migrans, can be asymptomatic or lethal ```
45
Describe the life cycle of Trichinella spiralis / Trichina worm infection
transmitted when pigs/ other farm animals are fed meat scraps that are infected, can also be transmitted by rats, larva encyst in striated muscle of host and are released in SI
46
What parasite is also called a whipworm
Trichuris trichiura
47
Where in the human body are Trichuris trichiura
larvae in SI adults in cecum unembryonated eggs passed in feces embryonated eggs ingested
48
What other name does Loa loa have
African eye worm
49
What vectors Loa loa
deer flies-day biters, Chrysops
50
Describe the life cycle of Loa loa in humans
Deer fly bites human introduces L3 onto skin larvae in subcutaneous tissue, adults produce diurnal microfilariae
51
Explain the how Loa loa migrate during the day and night
day-in peripheral blood | noncirculation phase-in lungs
52
Describe the Loa loa life cycle in its vector
deer fly ingests microfilariae, looses sheath and migrate from midgut to hemocoel to throacic muscle third stage larva migrate to probiscis to get into human skin during blood meal
53
What clinical symptoms does Loa loa cause
can be asymptomatic, might cause lymphatic dysfunction, elephantiasis night cough and wheezing with fever could cause ocular lesions that lead to blindness
54
How are Loa loa IDed in the lab
microfilaria are found in a blood smear
55
What vectors onchocerca volvulus
blackflies simulium
56
What disease does onchocera volvulus cause
onchocerciasis, riverblindness
57
Describe the Onchocerca life cycle in humans
L3 introduced to human skin by blackfly | larva develops in subcutaneous tissue into adult filariae, in nodules produces microfilariae
58
How long de Onchocerca live
adults-15 years produce microfilariae-9 years microfilariae-2 years
59
Where in the human body are Onchocerca usually found
skin. lymphatics of connective tissue
60
Describe the Onchocerca life cycle in its vestor
blackfly-ingests during blood meal microfilariae go to midgut, develop into L1-L3 Migrate to proboscis to reach human skin
61
What pathology does onchocerca cause
loss of elasticity and pigment in skin plugged up lymph vessels blindness caused by migrating larva in cornea
62
What disease does wuchereria bancrofti cause
brancroftian filariasis, elephantiasis
63
What parasite causes filariasis/elephantiasis
Brugia malayi and Wuchereria bancrofti
64
What disease does Brugia malayi cause
brugian filarisis, elephantiasis
65
What vectors filariasis
culex, anopheles, aedes, mansonia and coquillettidia all mosquitoes
66
Describe the life cycle of filariasis in humans
mosquito introduces L3 onto human skin adults in lymphatics produce nocturnal microfilariae migrate to lymph and blood chanels
67
What physical characteristic do filarial worms that help distinguish them
double uterus
68
Describe the life cycle of filariasis in its vector
mosquito ingests microfilariae from blood meal, goes to midgut L1-L3 in thoracic muscles L3 migrates through hemocoel to probiscis to reach human skin
69
What is the pathology of Filariasis
enlargement of lymph nodes, elephantiasis
70
Describe the Dirofilaria life cycle
adult worms in RV and Pulmonary artery of dogs microfilariae circulate blood larvae develop in mosquito mosquito can transmit to dogs and humans
71
What vectors dirofilaria
mosquito Culex
72
How long does it take for Dirofilaria to develop
180 days in dogs | never mature in humans
73
What disease does dirofilaria immitis cause
canine heartworm
74
What symptoms does Dirofilaria cause in humans and dogs
humans-asymptomatic, lesions in lungs seen in radiological exams, nodules caused by dead or dying worms that can become necrotic or calcified
75
what disease does dracunculus medinensis cause
guinea worm, fiery serpent
76
How is Drancunculus medinensis transmitted to humans
by drinking water contaminated with L3 copepods
77
Explain the Drancunculus medinensis life cycle
human drinks contaminated water with copepods larva released when copepods die larva penetrate stomach and intestinal wall where they mature or reproduce F migrate to skin and discharge larvae into water copepod consumes larvae
78
What symptoms does Drancunculus medinensis cause
blisters on skin, lesions on feet or legs. | worm emerging from legion

Parasitology (18 decks)

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