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Microbiology and Immunology 2500 - Virology > Parasitology I > Flashcards

Parasitology I Flashcards

1
Q

Enteric protozoa. What are the infective and active forms? Where can they be acquired from and when?

A

Found in our gut due to contaminated food or water. Not normal flora.

Cysts are the infective form - smaller, stable, can be transmitted.

Trophoziotes are the active form - cause symptoms.

Acquired from foreign travel and domestic camping. Long incubation period.

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2
Q

How are enteric protozoa diagnosed?

A

Stool tests. 3 to 5 stool specimens must be negative to rule it out.

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3
Q

Is a protozoa a euk or prok?

A

Euk, unicellular

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4
Q

What is most likely to cause traveller’s diarrhea?

When is the exception to this?

A
  1. Bacteria (85%)
  2. Parasitic (5-15%)
  3. Viral (<5%)

HOWEVER: if a bunch of people on a trip get diarrhea all at once, it is more likely that it is viral.

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5
Q

What are the three most common causes of traveller’s diarrhea? Which of the three is the most common?

A
  1. Giardia intestinalis (most common)
  2. entamoeba histolytica
  3. dientamoeba fragilis
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6
Q

What type of enteric protozoa is also known as “beaver fever”?

A

Giardia intestinalis (lamblia). Has very small cysts. Non-invasive. Resistant to chlorination, iodination is more effective. Residual lactose intolerance.

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7
Q

What is interesting about Dientamoeba fragila?

A

There is no cyst form. Only a trophozoite form. How is it infectious? By transmission on pinworm eggs. All people have had this before. 4 “teardrops” together in the cell. Non-invasive. Foul smelling.

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8
Q

What is a key symprtom of entamoeba histolytica?

A

Nondysenteric - alternating constipation and diarrhea. Invasive and may lead to systemic spread, causing amebiasis (colon ulceration). This can cause systemic spread to the liver, brain and lungs. NOT foul smelling. amoeba sera test = positive.

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9
Q

Cryptosporidium parvum.

A

Non-travel associated enteric protozoa. Very very infectious. Only 10 oocytes needed. Farm run-off, swimming pools, and splash parks. Found in animals and birds. Self-limiting unless immunocompromised. 10-20 bowel movements per day for the rest of your life. Stains acid-fast.

OOCYSTS

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10
Q

Cyclospora cayetanensis

A

Non-travel associated enteric protozoa. Associated with imported fruits from tropical locations. Long symptoms. Stains acid-fast.

OOCYSTS

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11
Q

What percentage of people with malaria will die?

A

1/3

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12
Q

What are the five types of enteric protozoa?

A

TRAVEL ASSOCIATED

  1. giardia intestinalis
  2. entamoeba hystolitica
  3. dientamoeba fragila

NON-TRAVEL ASSOCIATED

  1. Cryptosporidium hominis and parvum
  2. Cyclospora cayetenensis
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13
Q

How is malaria transmitted?

A

Anopholes species. Much larger than regular mosquitos. Bite at a 45 degree angle with lifted rear legs. Dusk to dawn biters. Attracted to heat and carbon dioxide. Only females bite, only females sing. Need a blood meal to reproduce. Fill by blood pressure.

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14
Q

What causes the periodicity of the fever in malaria?

A

48-72 hour fever that occurs like clockwork. This cycle is caused by a mosquito regurgitating saliva into the human bloodstream. Enters the liver quickly. Forms a schizont (cyst full of merozoites). Merozoites are released and infect RBCs, feeding on heme. Go through a cycle that keeps forming schizonts and subsequent merozoites.

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15
Q

What is the definitive host of Malaria?

A

An anopheles mosquito (reproduces there sexually = better)

Human is an “accidental host” (reproduces asexually = not better)

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16
Q

What are the five species of plasmodium? What do they cause?

A
  1. Plasmodium malariae
  2. Plasmodium knowlesi
  3. Plasmodium falciparum
  4. Plasmodium vivax
  5. Plasmodium ovale

They all cause malaria

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17
Q

P. vivax

A

Schüfners stippling, granular cells. Prefers young RBCs. The red blood cell becomes grossly enlarged.

Does not make “little delicate rings” instead big blobby amoeboe forms of the parasite.

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18
Q

What is characteristic about P. falciparum?

A

Delicate ring forms. The uninfected red blood cells are normal in size and texture.

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19
Q

How can you protect yourself from malaria?

A

Deet repellent, bednets, screens and air conditioners, anti-malarial medications

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20
Q

How do mosquito repellents work?

A

Not by smell. Forms a film on the skin that penetrates cuticle (skeleton). Confuses mosquito so they forget why they landed. They leave without biting.

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21
Q

Toxoplasma gondii

A

Many people are infected but asymptomatic. Can cause myocarditis (sudden death). NEONATAL INFECTIONS: Occasionally encephalitis, hydrocephalitis,

microcephaly (no frontal cortex development).

IN IMMUNOCOMPROMISED HOSTS: retinochorioditis

Raw meat. only tachyzoite form is active.

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22
Q

How are taxoplasma gondii infections acquired?

A

By consumption of raw meat

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23
Q

What can cause retinochoroidits in immunocompromised individuals?

A

Toxoplasma gondii, tachyzoite grows in the back of the eye and causes blindness

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24
Q

What are the two types of toxoplasma gondii?

A
  1. Bradyzoite - slow-growing and cystic
  2. Tachyzoite - fast-growing - active form that produces inflammation and tissue damage
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25
How can toxoplasma gondii affect the frontal lobes?
By causing increased ventricle size and **cysts of the frontal lobes,** affecting motivation and anxiety. hydrocephalitis or encephalitis
26
What is the definitive host of toxoplasma gondii?
The house cat, the ones that go outside and hunt raw meat. Stale cat feces are the hazards because the ova takes time to embryonate. Pregnant women should be careful.
27
Also known as "sandfly fever" as the vector is a sandfly.
Leishmaniasis - sandflies are the vectors
28
How can you differentiate a sandfly from a mosquito?
They are smaller, and they fold their wings above them. Mosquitos fold their wings on their back. Hover at ground level.
29
What does a sandfly inoculate with Leishmaniasis?
Promastigotes, which transform into amastigotes in the cells of the Reticular Endothelial System (bone marrow, spleen and liver)
30
What makes up the RES?
the liver, spleen, and bone marrow
31
What are the three different types of Leishmaniasis?
L. tropica = cutaneous, Baghdad boil L. braziliensis = subcutaneous **L. donavani = visceral = Kala azar**
32
What is the cutaneous form of Leishmaniasis?
L. tropica - "Baghdad" sores, may also look like leprosy PUNCHED OUT leg ulcers
33
What is the mucocutaneous Leishmaniasis?
L. braziliensis - causes chiclero ulcers, and deterioration of the nasal septum
34
What may present as "punched out ulcers" or like leprosy?
Baghdad sores on lower legs from Leishmaniasis tropica - cutaneous
35
What causes kala azar?
Leishmaniasis donavani - visceral
36
What may cause chiclera ulcers?
Mucocutaneous L. braziliensis
37
What may cause deterioration of the nasal septum?
mucocutaneous Leishmaniasis braziliensis known as espundia
38
What are the three stages of mucocutaneous leishmaniasis braziliensis?
1. Cutaneous 2. Cicatrical (think chicklets) - causes scarring 3. mucocutaneous espundia - deterioration of the nasal septum
39
Why does mucocutaneous leishmaniasis appear on the face and neck?
Harvesting chickle sap
40
What disease is the "great imitator"?
Syphilus
41
What happens in kala azar?
Visceral organs are infected. Infects RES. Spleen enlargement
42
What are the two types of trypanosomiasis?
T. cruzi (S.A. - chagas disease) T. brucei (African - sleeping sickness) from Pangaea splitting
43
What is the S.A. trypanosomiasis?
Chagas disease, caused by T. cruzi
44
What is the African trypanosomiasis?
T. brucei - sleeping sickness
45
What causes the 3 Cs?
From Chagas disease (Trypanosomiasis cruzi) 1. Chagus 2. Cruzi 3. C-shaped
46
How is chagas disease transmitted?
Kissing bug - defecate when they bite around the eyes, gets rubbed in causing disease
47
Does chagas disease infect the RES?
NO! Heart and digestive system
48
What causes chagas disease?
Trypsonomiasis
49
Causes organomegaly
Leishmaniasis donovani - visceral - kala azar
50
51
Compare and contrast Chagas disease (Trypanosomiasis cruzi) and Sleeping sickness (Trypanosomiasis brucei).
T. cruzi - chagas disease - kissing buds - NOT RES - c-shapes T. brucei - sleeping sickness - tsetse flies - RES - some c-shapes
52
What is transmitted by the tsetse fly?
T. brucei
53
What is transmitted by the kissing bug?
T. cruzi
54
How can a tsetse fly be depicted?
With a "hatchet wing"
55
What is the main symptom of sleeping sickness?
Enlarged **posterior lymph nodes.** Winterbottom's sign.
56
57
Naeglari fowleri
A free living amoebae, the most infectious. Free living amoeba can be found in warm, fresh water. Common in snorkelers. Causes meningitis, and are almost always fatal.
58
Free living ameboe
Neglaria fowleri acunthamoeba balamuthia mandrillaris sappinia pedata
59
60
What is another name for a roundworm?
Nematode
61
What is a tapeworm shape?
Cestode - segmented and flat, constructed of proglotid segments
62
What is a fluke's shape?
An unsegmented flatworm
63
Posterior lymphadenopathy
Sleeping sickness caused by T. brucie
64
Enterobius vermicularis (pinworm)
Intestinal nematode. Pinworm. Very common in children in lower intestine. Migrate out at night to lay eggs on anal skin. Use tape to see ova in the morning. OVA = round on one side, flat on the other Most common nematode infection in North America. Transmission by getting caught unfer fingernails after scratching.
65
What is the most common nematode in North America?
Enterobius vermicularis (pinworm)
66
What percentage of children are infected by enteriobius vermicularis (pinworm)?
30%
67
What are the 3 soil transmitted helminths?
Intestinal nematodes. Ascarius Hookwork Whipworm
68
Ascarius (intestinal)
Soil intestinal helminth nematode. Very very HUGE. Exist as male and female in the intestines. Sometimes - no eggs! No females. Usually large amount of eggs in stools. 2-3 embyonation in soil. Can emerge from nose or anus, but are usually asymptomatic. Can potentially obstruct **bile duct.** Upper small intestine. Can migrate to the lungs (pulmonary).
69
Where do pinworms embryonate?
On the perianal skin at night
70
Where does ascariasis embryonate?
Soil, 2-3 weeks
71
Ascariasis (pulmonary)
Coughing up blood, eosinophilia
72
What might a high concentration of eosinophils indicate?
Pulmonary ascariasis
73
What was anaphylaxis thought to have arisen from?
Reaction to clear intestinal worms
74
Whipworm
Soil, intestinal nematode HEAVY INFECTION: bowl prolapse in young children. Dysentery. Blood loss in stool. Trichuris dysentery syndrome: Anemia, **finger clubbing, growth stunting**
75
Hookworms
Soil embryo, intestinal nematode helminth. 20% of word infected. They suck blood. Some people consider them normal flora. Very small. risk factor is barefoot walking, penetrate intact skin. migrate into lungs, coughed up, swallowed, migrate into gut. Ground itch. **Cutaneous larva migrans. very itchy feet due to migrating larva.**
76
Risk factor of hookworm
Barefoot walking where a human, cat or dog has excreted a hookworm larva.
77
Helminth nematodes that pass through intact skin
Hookworm Threadworm (strongyloides)
78
What is the only helminth that can reproduce in the body?
Threadworm (strongyloides)
79
Threadworm strongyloides
Can reproduce in the body Can pass through intact skin Harmful if immunocompromised INTESTINAL, PULMONARY (very bad if immunocompromised), chronic skin (like hookworm), HYPERINFECTION SYNDROME (immunocompromised)
80
Raw fish worm (sashimi)
Anisakis
81
What is the risk factor for anisaki?
Raw fish
82
Anisaki
Raw fish extreme stomach pains
83
What are the intestinal nematodes?
pinworm ascaris whipworm hookworm strongiloides (threadworm) anisakis
84
What are the tissue nematodes?
trichinella spiralis guinea worm filariasis
85
trichinella spiralis
spiral shape undercooked pork (why it's banned by muslims and jews) achy muscles, periorbital edema (swollen eyes)
86
What does undercooked walrus, cougar jerkey, or pork give you?
Trichinella spiralis tissue helminth nematode
87
What are the 3 filarial nematodes?
1. subcutaneous filiarasis 2. lypmphatic filiarasis 3. serous cavity filiarasis named by the occupied body cavity
88
subcutaneous filariasis - river blindness
second most common cause of blindness worldwide transmitted by blackfiles (larvae) adults develop in subcutaneous nodules migrate to skin in daylight (chronic skin problems) MIGRATE TO CORNEA may be microfilaria which migrate EVERYWHERE (including the cornea)
89
What is transmitted by the blackfly?
subcutaneous filariasis, river blindness (onchocerca)
90
What is loa loa?
African eye worm (subcutaneous nematode)
91
Guinea worm
Subcutaneous, probably extinct now - use coffee filter when drinking water. 3 feet long!!! live in nodules of the lower legs. larvae are eaten by copepods, barely visible. People drink water. They migrate to the legs. second eradicated human disease (small pox too)
92
What is the second eradicated human disease?
The guinea worm
93
Wucheria
Elephantiasis (lymphatic filiarasis) mosquito acquired, blockage of lymph vesels
94
What innoculates promastigotes and makes them transform into amastigotes?
Leishmaniasis
95
Brady and tachyzoite
toxoplama
96
what has ova that are round on one side and flat on the other?
pinworm
97
periorbital edema
trichinella spiralis
98
winterbottoms sign
t. brucei sleeping sickness
99
What is the only helminth that can reproduce in the body?
Threadworm (male and female forms in the body)
100
How is filiarasis acquired?
Mosquitos
101
102
onchocerca
river blindness (filiarasis - subcutaneous)
103
wucheria
elephantiasis, lymphatic filiarasis
104
Two types of serous cavity filiarasis tissue nematides?
mansonella
105
Both male and female worms
Acarius
106
Rectal prolapse
Whipworm
107
Clubbed hands and growth stunting
threadworm
108
nocturnal pruitis
pinworm
109
trichius dysentery syndrome
=clubbed fingers whipworm
110
barefoot walking
hookworms although threadworm can invade intact skin as well
111
cutaneous larvae migrans
hookworm
112
only helminth that can reproduce in the body
threadworm
113
114
sashimi
anisakis
115
undercooked pork, walrus, cougar jerky
trichonella spiralis
116
prohibition of pork eating
trichonella spiralis
117
periorbital edema
trichonella spiralis
118
transmitted by blackflies
onchocerca
119
river blindness
onchocerca
120
copepods
guinea worm
121
how is wucheria acquired?
=lymphatic filiaris acquired by mosquitos - elephantiasis
122
most common cestode
dwarf tapeworm
123
not an obligatory human parasite
dwarf tapeworm
124
not

Microbiology and Immunology 2500 - Virology (12 decks)

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