Parasitology Lec 1 Test 1 Flashcards


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1

Malaria

  • Mal = bad
  • Aira = air

derivation of name

original theory of transmission: bad air inhaled from swamps (from water), not mosquitos

greatest infectious disease killer ever in the world

  • ppl knew something was killing / infecting people (didnt know what)
  • did not know its transmission until found out with bird malaria: discovered in canaries that mosquitos transmit it

2

malaria facts

  • in > 100 countries
  • > 280 million cases/year + increasing
  • kills > 500 k ppl/year + increasing
  • no vaccine (only in <5 yr olds)
    • need drug to be protected
  • highly resistant to drugs
  • vectors highly resistant to insecticides (ex: mosquitos)

- many ppl died during covid from malaria bc scared to go to hospital

3

Malaria species

  • plasmodium falciparum
  • P. vivax
  • P. malariae
  • P. ovale (rare and similar to vivax)
  • P. knowlesi (normally in monkeys, now in humans too)
    • bc cut in forest where monkeys were
    • new guinea, indonesia

4
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Dr. Seuss made book on malaria for the army

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  • how to avoid malaria

5

today, malaria in tropical belt across the world

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  • wiped out from US as of 1950s
  • only ones in US are imported

6

World wide malaria cases

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decreased drastically since 1900

some people think it will be eliminated by 2040

7

Anopheles sp. mosquitos

  • the only genus of mosquitos that are vectors of malaria

8

Potential malaria vectors today in USA

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  • transmit on very small scale in the US

9

noble prized for malaria

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10

life cycle of malaria

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  • sporozoa injected into human
  • -> into liver cell (multiply)
    • -> blood (merozoites)-> schizont
      • some -> germ cells -> picked up by new mosquito
      • some -> reproduce in blood making more merozoites
        • asexual cycle in blood cause pathology

11

more life cycle

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12

3 different drugs are needed to kill all stages of P. vivax malaria

  • mosquito inject sporozoites
  • -> migrate -> liver stage (delayed development in Vivax)
  • exoerythrocytic schizonts develop -> dev -> merosomes
  • -> merozoites lyse out of merosomes
  • -> blood
    • -> blood stage (schizonticides)
      • asexual blood cycle
    • -> gametocytes (gametocytocides)
      • new mosquito pick up

13

1 exoerythrocytic schizont in liver tissue can have _______ merozoites

30,000

14

merosomes from liver are

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bags of merozoites

merozoites get released from the merosomes in the liver

15

stages in liver

  • sporozoites: tachysporozoites (fast) and b radysporozoites (latent)
  • EE stage (exoerythrocytic schizont)
    • in every species of malaria w/ merozoites
  • hypnozoite (only vivax / ovale) = slow growing EE stage that makes merozoites months after infection

16

hypnozoites are what? what species are they in specifically?

hypnozoite - slow EE stage that makes merozoites months after infection (not like normal species do)

by vivax and ovale

17

receptors on endothelial cells inside veins for RBCs infected w/ falciparum

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endothelial receptor - glycophorin A, B, C for falciparum

parasite makes the receptor outside the RBC

receptor locks with endothelial cells to stay in blood, undetected

release when its ready

18

why does falciparum make these receptors outside RBCs that bind with endothelial cells?

so it does not keep flowing through blood

would be destroyed by the spleen

  • so it locks into endothelial cell to stay put + undetected

19

falciparum go in

normal RBC

20

receptors for vivax

  • duffy blood group antigens
    • receptors on human reticulocytes (immature RBCs) that vivax attaches to
  • reticulocytes = 2% of total RBC in blood
  • no bonding of endothelial cells w/ P. falciparum

21

reticulocytes

young RBC, the only place that vivax lives

only 2% of all RBC in body

22

receptors on parasites + cells they invade:

liver + RBCs + endothelia

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  • on sporozoites
  • on liver cells
  • merozoites
  • RBCs
  • endothelial cells
  • lining blood vessels

23

organelles for entry into RBCs

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how malaria get in RBC

  • swim blood
  • -> attach to RBC
  • -> secrete things
  • -> get in

24

parasite organelles involved in invasion of cells

  • rhoptry bodies
  • micronemes
  • dense granules
  • exonemes

all inside the merozoite

25

exonemes

used to enter + exit RBCs

  • in apical end of merozoites
  • activates host SERA proteases (SUB1) which helps merozoites escape from mature schizont
  • aids merozoites to enter a new RBC

26

infected RBCs with merozoites from schizonts (pic)

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just a pic showing the schizont w/ merozoites inside

27

parasite stages in RBCs

  • merozoites
  • rings - young trophozoites
  • trophozoites - mature
  • schizonts - once nucleus divides + keeps dividing
  • gametocytes - sexual stages
    • microgametocyte - male
    • macro gametocyte - female

28

apicoblast

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resembles a plastid in plants

important for the parasite

29

early ring stage

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very primitive organelles

cup-like form

30

trophozoite

irregular outline

increase in protein-synthesizing apparatus

increased feeding through multiple cytosomes

has food vacuoles - how take in food

growth of pigment vacuole

growth of structures associated w/ export of parasite proteins (golgi body, exocytic vesicles)

31

pigment structures cannot be digested

parasite leaves them -> makes the human's spleen black when these break open -> releasing the pigment into persons body

32

metabolism

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33

glucose is the substrate for energy production

lactate is the end product

  • makes lactate
  • can be deadly: lactate build in blood = acidic = acidosis in body

34

why is the lactate end product possibly deeadly?

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can cause acidosis in the human's body

bc lactate is acidic

35

apicoblast

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the plastid

see pic

36

pyrimidine synthesis is coupled with?

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  • have diff e- transport than normal cells
  • coupled w/ pyrimidine biosynthesis
  • joined at dihydroorotate step

37

mouth of parasite

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cytostome

38

malaria food vacuole

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  • parasite pickup hemoglobin
  • cannot digest heme
  • use hemoglobin to make amino acids
  • also neutralize free radicals/H2O2 (parasite not harmed by these)

39

parasite uses hemoglobin to make

amino acids

40

antioxidants

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we use these to protect ourselves

  • SOD Mn
  • SOD Fe
  • Glutathione
  • Peroxiredoxin (Thioredoxin)

41

summary of parasite development

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42

3 types of recurrent infections

  1. relapse - from dormant (hypnozoite) stages
    • P. vivax + P. ovale
    • infected -> dormant stage can stay for long time + release WAY later -> get it again after already infected before
  2. recrudescences - from incomplete treatment or partially effective host immune responses
    • all species
    • ex: hide in RBC (not liver)
  3. reinfections or multiple infections
    • all species

43

relapse

  • recurrence of parasitemia after its initial clearance
    • from parasites emerging from dormant hypnozoite stage in liver
  • anywhere from months-1 year after mosquito bite
  • only vivax/ovale

44

number of parasites in a 70 kg person w/ 1% parasitemia

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can be a LOT

why can get killed by parasite

(see pic)

45

malaria species difference: chart

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46

diagnosis: how malaria is diagnosed

  • blood films
    • thick - find parasites
      • let dry -> water (lyse RBC) = parasites left
    • thin - speciate for proper treatment
      • usually dont show
  • dipstick
    • antigen capture tests (dipsticks)
    • optimal dipstick - follow drug treatment
    • determine dipstick - doesnt follow drug treatment

47

thick films of person w/ both falciparum + vivax

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48

thin films for: (see slides)

  • p. falciparum
  • vivax
  • malariae

49

malaria dipstick method

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like rapid diagnostic test

50

malaria test results

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  • 1 control line - negative
  • 1 line - vivax
  • 2 lines - falciparum

51

summary

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