Pathogenic Protozoa II Flashcards

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1
Q

In the mitotic cycle, trophozoites grow and undergo multiple nuclear division cycles without cytokinesis to produce large multinucleate forms called

A

Schizonts

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2
Q

These then cleave (schizogeny) to produce multiple uninucleate infective progeny cells, released by

A

Host cell lysis

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3
Q

In apicomplexa, what are

  1. ) Rapidly-multiplying trophozoites
  2. ) Slow-multiplying trophozoites
  3. ) Semi-dormant trophozoites
A
  1. ) Tachyzoites
  2. ) Bradyzoites
  3. ) Hypnozoites
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4
Q

Kills more people than any infectious disease

A

Malaria

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5
Q

Malaria plasmodia are transferred to humans by which three mechanisms?

A
  1. ) Bite of female anopheles mosquito
  2. ) Blood transfusion
  3. ) Maternal-fetal route
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6
Q

What are the 4 species of plasmodium that infect humans with malaria?

A
  1. ) Falciparum
  2. ) Malariae
  3. ) Ovale
  4. ) Vivax
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7
Q

Monkey parasite recently shown to infect humans

A

Plasmodium knowlesi

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8
Q

Found in all subtropical and tropical areas of the world except deserts, usually found below 1800m elevation

A

Malaria

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9
Q

Was once endemic in the eastern and central United States, but extensive mosquito control efforts have eradicated it as an epidemic disease

A

Malaria

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10
Q

What are the three diseases that give heterozygotes immunity to malaria

A
  1. ) G-6-P deficiency
  2. )Thalassemia
  3. ) Sickle-cell anemia
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11
Q

In mammals plasmodia first replicate in the liver. This is followed by multiplication and then gamete formation in

A

Red cells

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12
Q

After transmission to humans, plasmodia first infect and multiply in

A

Liver cells

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13
Q

The form of plasmodium most infectious to humans is the

A

Sporozoite

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14
Q

Each infected liver cell releases thousands of merozoites into the bloodstream and these infect and multiply in

A

Erythrocytes

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15
Q

Are not infectious for hepatocytes so there is no re-infection of the liver

A

Merozoites

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16
Q

Merozoites are infectious for

A

Erythrocytes

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17
Q

The only part of plasmodium that is infection to mosquitos is the

A

Gametocytes

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18
Q

Microgametocytes produce flagella (exflagellation) and produce

A

Motile gametes

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19
Q

In the gut these fertilize the larger macrogametocytes to form motile zygotes (ookinetes) which invade the gut wall and

A

Encyst (Oocysts)

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20
Q

Oocysts then undergo sporogeny: they first grow and then divide to produce multiple sporozoites (the infectious form for mammals), which move to the mosquitos

A

Salivary glands

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21
Q

Undergo only a single cycle of replication in the liver

A

P. falciparum and P. malariae

22
Q

Remain in liver as dormant hypnozoites which can persist long after erythrocytic forms have disappeared

A

P. vivax and P. ovale

23
Q

Can produce recrudescent infection of the liver and bloodstream for several years after the initial infection has lapsed

A

P. vivax and P. ovale

24
Q

By the time symptoms appear, P. falciparum and P. malariae have no liver stage, and therapy can be targeted to the bloodstream forms alone. This is called

A

Suppressive cure

25
Q

The other species require therapy sufficient not only to remove bloodstream infection but to eradicate slow-replicating hypnozoites from the liver and prevent relapse. This is called

A

Radical Cure

26
Q

In the erythrocytic cycle, a merozoite infects an erythrocyte and becomes a

A

Vacuolated ring form

27
Q

This enlarges [trophozoite], undergoes nuclear division [developing schizont] and finally cleaves [schizont] to produce numerous new

A

Merozoites

28
Q

Plasmodia degrade and catabolize hemoglobin. The released hematin precipitates to form granules of

A

Malaria pigment

29
Q

In P. vivax/ovale infections the granules are coarse and known as

A

Shuffner’s dots

30
Q

After erythrocyte lysis this pigment is phagocytosed by reticuloendothelial cells and produces

A

Gray/black tissue discoloration

31
Q

Malaria transmission is followed by an incubation or prepatent period, before the onset of symptoms. This period lasts

A

1-4 weeks

32
Q

Cycles of erythrocyte infection and release of merozoites may become highly synchronized. Waves of erythrocyte destruction produce waves of

A

Chills and fever

-Then sweats as fever relapses

33
Q

Malaria diagnosis is by

A

Blood smear

34
Q

Bouts of fever are often accompanied by headache, nausea/vomiting, and malaise. As disease continues, we see anemia, cachexia, and

A

Enlargement of liver and spleen

35
Q

In severe cases, especially of falciparum malaria, there may be extensive hemolysis with hemoglobin in the urine. This is called

A

Blackwater fever

36
Q

In falciparum malaria infected red cells at post-ring stages adhere to

A

Endothelium

37
Q

Are both involved in recovery from anemia

A

Humoral and cell-mediated immunity

38
Q

Produces some degree of immunosuppression, as measured by decreased response to vaccine antigens

A

Malaria

39
Q

There is also polyclonal B cell activation. These can interact with latent infection with Epstein-Barr virus to promote development of the B-cell tumor known as

A

Burkitt’s lymphoma

40
Q

Bloodstream infection with a given strain of Plasmodium produces a state of low level immunity to

A

Antigenically similar strains (premunition)

41
Q

Requires the continued presence of plasmodia; once bloodstream infection lapses, immunity wanes and re-infection can occur

A

Premunition

42
Q

The origin of the gin and tonic because the drink was used to mask the taste of

-Could cure malaria

A

Quinine

43
Q

Act by inhibiting the enzyme heme polymerase

-Still used in the treatment of CNS malaria

A

Quinine

44
Q

Contain a non-photosynthetic plastid with a genome like that of chloroplasts

A

Plasmodia

45
Q

What are the three genera of Microsporidia that infect humans?

A

Encephalitozoon, Enterocytozoon, and Nosemia

46
Q

Transmission is via contaminated food or water. Life cycle is similar to that of Apicomplexa

A

Microsporidia

47
Q

Microsporidia multiply intracellularly. The infectious form is the

A

Spore

48
Q

When a spore contacts a host cell the filament everts and pierces the host-cell plasma membrane. Osmotic flow of water into the spore forces the cytoplasm of the parasite through the polar filament and into the

A

Cytosol of host cell

49
Q

Have the smallest genomes of any eukaryotes, about 2 mb, smaller than many bacteria

A

Microsporidia

50
Q

Mostly intestinal, eye, or systemic infections, although any tissue can become infected

A

Microsporidia Infection