Protozoans and Biting Insects Flashcards

1
Q

Describe the life cycle of leishmania

A

sand fly life cycle:
o Sand fly takes meal of blood cells with amastigotes (no flagella)
o Amastigotes transform into promastigotes in fly’s midgut
o Promastigotes multiply by binary fission in midgut and are then injected into new host during next blood meal
o Human macrophage ingests the parasites
o Promastigotes transform into amastigotes and multiply in macrophage
o Macrophage ruptures and amastigotes are released into the blood stream where they can infect more macrophages

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2
Q

promastigote

A

has a flagella, seen in the sand fly

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3
Q

amastigote

A

has no flagella- seen in mammalian host of leishmania

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4
Q

leishmania tropica

A

causes oriental sore - ulcer, can be immune following innoculation

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5
Q

leishmania donovani

A

causes Kala-azar (visceral leishmania)- amastigote goes to any organ/skin and kills it, usually leads to death in a few years because person has no macrophages to protect them
 Post-Kala-azar dermal leishmanoid- if not treated a disfigurement of the lesion occur

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6
Q

What is T. brucei?

A

tsetse fly, African sleeping sickness, organisms replicate in blood and get into the organs, cause lymph node swelling and massive immune stimulation. Undergoes lots of antigenic variation via transposons

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7
Q

Which T. brucei is chronic? Which is acute?

A

Chronic- T.b. gambiense

Acute- T.b. rhodensiense

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8
Q

Stercoraria

A

complete development in the hindgut (people scratch the feces from parasite into the opening in their skin

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9
Q

T. cruzi

A

kissing bug, t. cruzi related to CHAGAS disease

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10
Q

Life cycle of T. cruzi

A

o Kissing bug ingests trypomastigoes during blood meal
o Trypomastigotes form epimastigotes by binary fission in midgut of kissing bug, and they transform into more trypmastigotes in the hindgut of kissing bug
o Trypomastigotes deposited in feces of kissing bug at wound site, scratched into the blood
o Trypomastigotes travel in blood and penetrate cells, transform ito amastigotes
o Amastigtes multiply in cells and infected tissues
 Can infect other cells
 Can transform into trypomastigotes in blood

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11
Q

ramona’s sign

A

lymph node swelling associated with t.cruzi (kissing bug)- CHAGAS DISEASE

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12
Q

T. cruzi is ____cellular

A

intracellular, organism replicates in phagocytes.

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13
Q

describe t. cruzi pathology

A

forms a pseudocyst (pocket of parasites in muscle or brain or heart tissue) causing inflammation that can lead to death, Chagas disease (megaesophagus and megacolon)

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14
Q

what does entamoeba histolytica cause?

A

amoebic dysentery- organism ingests RBCs and eats into intestinal mucos (causes erosions) and can spread to liver and lungs and CNS

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15
Q

How many nuclei does entaoeba histolytica have?

A

4 nuclei in cyst form, one nuclei as trophozoite (central endosome in nucleus)

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16
Q

What does giardia lamblia cause?

A

diarrhea (like campers/ traveler’s disease), pear-shaped trophozooite with 2 nuclei (look like eyes), causes fat-laden smelly stool with no blood

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17
Q

What is trichomonas vaginalis associated with?

A

STD, associated with vaginitis in women

undulating membrane on trophozoite

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18
Q

What is associated with Balantidium coli?

A

ciliar dysentery, get this from pig feces, stays in intestine

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19
Q

What is associated with cryptosporidium parvum?

A

diarrhea in immunocompromised, outbreak in Milwaukee; acid fast stain used for diagnosis

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20
Q

Which state is motile and inactive? Which state is infective?

A

o Trophozoite stage- motile form, inactive

o Cyst stage- Infective stage, spherical shape

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21
Q

How do you distinguish cyst vs. trophozoite in entamoeba histolytica?

A

4 nuclei in cyst form, 1 nucleus in troph form (central endosome in nucleus)

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22
Q

Which intestinal protozoa has a kidney shaped macronucleus with cilia around it?

A

balantidium coli

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23
Q

name the three stages of the plasmodium life cycle and where each stage occurs

A
pre-erythrocytic cycle (exo-erythrocytic cycle)- in liver
erythrocytic cycle (in RBCs)
sporogonic cycle (in mosquito)
24
Q

What is the most significant disease transmitted by fleas?

A

plague

25
Q

protozoans are ___cellular

A

unicellular, but multicolonial

26
Q

Where is P. vivax common? Why?

A

Asia, Africans have anti-Duffy blood type so not affected by this form of plasmodium

27
Q

Which plasmodium types cause tertian malaria? Which plasmodium types are quartan?

A

P. vivax, P. ovale are tertian.
P. malariae is quartan
P. falciparum has no tertian pattern in symptoms (incessant)- malignant tertian)

28
Q

What is different about P. malariae?

A

quartan malaria, enters aging RBCs, has recrudescence

29
Q

Which forms of malaria have relapses from the liver?

A

P. vivax and P. ovale

30
Q

T. gondii

A

causes toxoplasmosis (myalgias, rash), cats are definitive host, intracellular parasite (in cat); pregnant women should stay away from litter boxes

31
Q

Acanthamoeba

A

get infected when contacts are washed with water, can cause keratitis in eyes and can invade CNS causing granulomatous ameobic encephalitis

32
Q

naegleria

A

infected water gets into nose, and the trophozoites migrate to the brain causing primary ameobic meningoencephalitis (trophozoites found in CSF)

33
Q

How can protozoans reproduce?

A

Asexually or sexually
asexual- schizogony (multiple fission –> schizont–> merozoite)
sexual- makes gametocytes

34
Q

True or false: P. falciparum releases more merozoites/RBC than other species, making it more virulent than other forms of malaria

A

TRUE

35
Q

T/F: there are continuous symptoms during p. falciparum infection

A

TRUE; no spontaneous recovery in p. falciparum.

36
Q

Describe recrudescence. What parasite causes this?

A

In recrudescence the parasite is present in low levels and replicatimg slowly, so many years later you are symptomatic.
Occurs in plasmodium malariae since it only enters aging red blood cells.

37
Q

What is the diagnostic stage of plasmodium?

A

Trophozoite (ring stage) in erythrocytic cycle (in RBC)

38
Q

clinical manifestations of malaria are due to…

A

the erythrocytic stage of the life cycle (merozoites infect RBCs, replicate, and burst the cells)

39
Q

What is infectious stage of plasmodium?

A

release of sporozoites in the anopholes mosquito to the salivary glands, for entrance into host via mosquito bite

40
Q

Where does sexual division occur in plasmodia? Where does asexual division occur?

A

sexual - in anopheles mosquito

asexual- in liver cell and RBC of host (human)

41
Q

Who is resistant to p. falciparum?

A

sickle cell patients

42
Q

Who has milder p. falciparum symptoms?

A

G6P dehydrogenase deficiency patients

43
Q

Why is p. vivax seen more in Asia than Africa?

A

Some Africans lack Duffy antigen, which is needed for plasmodium to get into the cell

44
Q

What are the three main symptoms of malaria?

A
  1. chills and rigors
  2. fever spikes
  3. sweating
45
Q

tertian malaria means…

A

1 day of symptoms every 48 hours (3 days total for cycle)

46
Q

P. vivax only affects ____ cells

A

affects young cells

47
Q

hypnozoites are ____ and are associated with ____

A

liver cell dormant phase
p. vivax and p. ovale
hypnozoites can cause a relapse when they become active again.

48
Q

describe quartan malaria

A

24 hours of feer, 72 hours of feeling well (4 days total); typical of p. malariae which infects older RBCs

49
Q

which malarial forms have spontaneous recovery?

A

p. vivax and p. ovale

however, these have hypnozoites which can be dormant and cause a relapse

50
Q

paroxysm means…

A

sudden appearance of symptoms

51
Q

malaria is treated with:

A

quinine

52
Q

Why is it hard to make a vaccine for malaria?

A
  1. organism continuously changes protein coat

2. each reproductive stage has different antigens

53
Q

How are humans infected by toxoplasma gondii?

A

Remember, this is transmitted by cats

  • eating undercooked meat of animals harboring tissue cysts.
  • consuming food or water contaminated with cat feces (fecal-contaminated soil or changing the litter box of a pet cat).
  • blood transfusion or organ transplantation.
  • transplacentally from mother to fetus.
54
Q

What is infective phase of leishmania?

A

sandfly takes a bloodmeal and injects promastigotes into host

55
Q

What is the diagnostic phase of leishmania?

A

amastigotes in macrophages and tissues

56
Q

What does heteroxenous mean?

A

requiring more than one host to complete the life cycle (example: leishmania, plasmodium, trypanosomes)