Parasites Flashcards
1
Q
What are protozoa?
A
Unicellular eukaryotes.
2
Q
What is the cyst form of a protozoa?
A
Tough protective layer outside plasma membrane to protect against inhospitable environments.
3
Q
What is the trophozoite form of a protozoa?
A
Growing form without a cyst wall.
4
Q
What do we call the cyst form of a protozoa when it is a sexually reproducing organism?
A
Oocyst.
5
Q
What is a characteristic symptom of Entamoeba histolytica?
A
Bloody diarrhea.
6
Q
Does Entamoeba histolytica have a cyst form?
A
Yes.
7
Q
The cyst/oocyst form of some parasites have a high degree of ________ resistance. Why is this especially problematic?
A
chlorine.
Our drinking water is usually treated with chlorine so they can exist comfortably in tap water.
8
Q
Why can some parasites (Entamoeba histolytica, Giardia lamblia, Trichomonas vaginalis) be treated with metronidazole (an antibiotic)?
A
They are anaerobic parasites and the antibiotic targets anaerobic organisms.
9
Q
What is a major sign of giadiasis (“Beaver fever”, caused by Giardia lamblia)?
A
Flatulence (gas) & diarrhea.
10
Q
Does Giardia lamblia have a cyst form?
A
Yes.
11
Q
Giardia lambia can be found in _____ because it has a ________.
A
water, flagella.
12
Q
Does Trichomonas vaginalis (“trich”) have a cyst form?
A
No.
13
Q
How is Trichomonas vaginalis spread?
A
Person-to-person via sexual transmission.
14
Q
Where can Trichomonas vaginalis be found?
A
In the vagina & male urethra.
15
Q
What are symptoms of Trichomonas vaginalis?
A
Itching & inflammation of tissues.
16
Q
Acanthamoeba are trophozoites in _____ and cysts in ____.
A
water, dust.
17
Q
Acanthamoeba are often found in the ___, which is why they are often problematic for those who wear ______ ______.
A
eye, contact lenses.
18
Q
What is the outcome of Acanthamoeba infection?
A
Vision or eye loss.
19
Q
Cryptosporidium parvum reproduces ________, which means they have _______.
A
sexually, oocysts.
20
Q
Where do we usually find Cytosporidium parvum?
A
Animals like cows, rats, dogs & cats.
21
Q
How do people usually get Cytosporidium parvum?
A
Water contaminated with animal manure.
22
Q
What is a characteristic symptom of infection by Cytosporidium parvum?
A
Chronic diarrhea.
23
Q
Toxoplasma gondii is _________ reproducing, so they have an ______ form.
A
sexually, oocyst.
24
Q
Where is Toxoplasma gondii usually found?
A
Cat feces.
25
How is Toxoplasma gondii usually acquired?
Eating uncooked meat with tissue cysts or contact with cat feces.
26
Which demographic of people is Toxoplasma gondii particularly dangerous for?
Pregnant women.
27
Trypanosoma are _____ parasites.
blood
28
How is Trypanosoma usually transmitted?
vectors - bugs.
29
What are the two types of Trypanosoma we need to know and to where are they endemic?
T. brucei gambienese/rhodesience in Africa.
| T. cruzi in South America.
30
What is the vector of transmission for Leishmania?
The sandfly.
31
Describe the 3 different degrees of infection for Leishmania from most to least serious?
Visceral: affects internal organs.
Mucocutaneous: parasite eats cartilage.
Cutaneous: sores on skin.
32
How does Leishmania grow & avoid destruction by macrophages?
They live & develop in macrophages and affect the macrophage's killing ability so they can grow safely.
33
Plasmodium species is the cause of _______.
malaria.
34
What are the 5 types of Plasmodium that we have to know?
1. P. falciparum.
2. P. malariae.
3. P. ovale.
4. P. vivax.
5. P. knowlesii (new).
35
What is the most dangerous type of Plasmodium and why?
P. falciparum because it targets all ages of RBCs.
36
Why are symptoms of infection by P. falciparum?
```
Fevers & chills (toxic breakdown products of RBC destruction).
Cerebral malaria (sequestration of parasites & RBCs blocking blood vessels & causing organ death).
Anemia (due to lysis of RBCs).
Kidney failure (too many Hemoglobin breakdown products).
```
37
Where is the focus of infection for Plasmodium?
The liver.
38
When do we take blood to test for Plasmodium?
Fever - highest chance of finding it at that time.
39
What are metazoa?
Multicellular organisms (helminths)
40
What are the 3 major groups of worms causing human infection?
Nematodes, trematodes & cestodes.
41
What are 2 characteristics of nematodes?
Round, have a complete digestive system.
42
What are the 2 categories of nematodes & nematode infection?
Eggs as the infective stage.
| Larva as the infective stage.
43
Enterobius vermicularis is also known as _______.
Pinworm.
44
Pinworm has ____ as the infectious stage.
eggs.
45
Where do pinworms live?
Large intestine.
46
Where & when do female pinworms go to lay eggs?
The external skin of the anus at night.
47
Which demographic is pinworm most common & most infectious in?
Kids.
48
How are pinworm eggs transmitted?
Direct contact with eggs or ingestion of eggs stirred up in dust.
49
Where can Ascaris lumbricoides usually be found?
Small intestine of pigs, cows, horses.
50
Ascaris lumbricoides has ____ as the infectious stage.
eggs.
51
What is the most common way for humans to get Ascaris lumbricoides?
Ingestion of eggs through unwashed or untreated foods (ex: vegetables fertilized with animal manure).
52
Where do Ascaris lumbricoides eggs hatch and where do they go from there?
Hatch and become larvae in intestine → lungs → trachea → nose or mouth (children) OR back to intestine (adults).
53
Why can Ascaris lumbricoides exit through the nose/mouth of children but not adults?
Children lack a well-defined swallowing reflex so the worms have no way of being swallowed down into the stomach.
54
Adult Ascaris lumbricoides are ________ - they have distinct _____.
dioecious, sexes.
55
How do we diagnose Ascaris lumbricoides infection?
Examining feces for eggs.
56
Hookworms have ______ as the infectious stage.
larva
57
Where do hookworms enter into the body and where do they go from there?
enter through intact skin of bare feet → lymphatic system → circulatory system → lungs → coughed up & swallowed down to small intestine, where they attach by hooks on the scolex (head)
58
Hookworms suck _____, causing ______.
blood, anemia.
59
Hookworms are only found in ____ climates.
warm
60
Anisakis have _____ as the infectious stage.
larva
61
Where can Anisakis usually be found?
Fish.
62
How do humans usually get Anisakis?
Ingesting low-quality, raw fish.
63
Trichinella spiralis has _____ as the infectious stage.
larva
64
How do humans usually get Trichinella spiralis?
Ingesting encysted larvae in undercooked pork, boar, bear & walrus.
65
What is a characteristic symptom of Trichinella spiralis?
Muscle weakness.
66
Blood nematodes have _____ as the infectious stage.
larva
67
What are the two notable blood nematodes infections?
Elephantiasis (lymphatic filariasis) & river blindness (onchoceriasis).
68
Where are blood nematodes prevalent?
Africa, Asia, tropical Latin America.
69
How are blood nematodes commonly transmitted?
Mosquitoes.
70
Trematodes are ____-shaped & much _______ than nematodes.
leaf, smaller.
71
What is the most prevalent type of trematode?
Schistosoma.
72
How do Schistosoma adults hide from the immune system?
They have a protein coat stolen from the host.
73
Where do Schistosoma worms reside inside the body?
The venous plexus of the bladder or the intestine.
74
Where are ectoparasites found?
On skin
75
What are the 2 types of ectoparasites?
Sarcoptes scabei and lice
76
Secondary infections for lice occur when:
Lice feces are crushed into wounds
77
What parts of the body does sarcoptes scabei infect?
Finger webs, elbows, armpits, breasts, groin and buttocks
78
Describe sarcoptes scabei
Mites burrow into skin, feed, mate, and lay eggs
79
What are the usual hosts of sarcoptes mites?
Not humans, animals (ie. dogs)
80
What is the most dangerous type of tapeworm and why?
Pork tapeworm (Taenia solium): person-to-person transmission & can cause damage to nervous system.
81
Lice penetrate the skin to:
Suck blood
82
Female lice glue eggs to ____ ____ which hatch in _-_ days
hair shaft, 5-10
83
Secondary infections for lice occur when:
Lice feces are crushed into wounds
84
The lifespan of sarcoptes scabei is:
30 days
85
What are the 3 types of Schistosoma we need to know?
S. haematobium.
S. japonicum.
S. mansoni.
86
Cestodes are _________ on their host for nutrients because they don't have a ________ ______.
dependent, digestive system.
87
The body of a cestode consists of segments called __________ which contain male and female ___________ ______.
proglottids, reproductive organs.
88
Cestodes are also known as __________.
tapeworms.
89
How do humans get tapeworm?
Eating inadequately cooked contaminated beef, pork or fish.
90
What are the 2 diseases that tapeworm can cause?
Intestinal infection or deep tissue infection.
91
What is the most dangerous type of tapeworm and why?
Pork tapeworm (person-to-person infection & can cause cysts in the brain).
92
What is the least dangerous type of tapeworm?
Beef tapeworm (Taenia saginata).
93
When we eat undercooked beef, we are ingesting beef tapeworm ______.
larvae
94
Where do beef tapeworms mature in the human body?
The intestine.
95
Humans are considered ____ _____ for dog tapeworm.
Dead hosts.
96
What are the 2 modes of infection for pork tapeworm?
Eggs and larva.
97
What is the vector for Babesia microti?
Ticks (Ixodes sp.)
98
Is Babesia microti a protozoal or metazoal infection?
Protozoal.
99
Where is Babesia microti commonly found?
Northeastern US.
100
What kind of human body cells does Babesia microti replicate in?
RBCs.
101
What does Babesia microti cause?
Hemolysis & anemia.
102
How severe is Babesia microti infection considered in most people?
Mild to moderate.
103
How is the Dracunculia species (Guinea worm) transmitted?
Fecal-oral.
104
Where does the Guinea worm go in the body?
They penetrate the intestines & travel in the subcutaneous tissue.
105
How do Guinea worms exit the body?
They cause a blister, which erupts and allows the worm to emerge.
106
What happens when the Guinea worm senses water?
They release their larvae into the water.
107
How could you treat someone with Guinea worm?
Slowly pull the worm out 1 inch per day so it doesn't break & cause inflammation.
108
Trichuris trichuria (whipworm) usually infects which demographic of people?
Children.
109
Whipworm is usually found in ________/__________ countries & climates.
tropical/subtropical.
110
Whipworm is usually associated with ___ feces.
rat.
111
Whipworm is relatively benign, meaning those infected are usually ____________.
asymptomatic.
112
Hymenolypsis nana is the most ______ tapeworm globally.
common.
113
Hymenolypsis nana is usually found in ________ areas & climates.
tropical.
114
Hymenolypsis nana doesn't need an "intermediate host", which means it can:
autoinfect a human.
115
Those infected with Hymenolypsis nana often exhibit ___ symptoms.
few.
116
How is Hymenolypsis nana transmitted?
Fecal-oral: ingestion of eggs.
117
Hymenolypsis nana can cause tissue damage, leading to symptoms of:
enteritis (inflammation of small intestine), diarrhea, cramps.
