Malaria

Question 1

malaria: which parasite causes malaria?

Answer 1

plasmodium

Question 2

malaria: which types plasmodium cause malarian disease in humans?

Answer 2

P. vivax
P. falciparum
P. malariae
P. ovale
P. knowlesi

Question 3

what type of pathogen is plasmodium?

Answer 3

parasites (single cell)

Question 4

how does plasmodium get spread?

Answer 4

via mosquitoes

Question 5

what kind of cells do plasmodium enter and destroy?

Answer 5

liver cells and RBCs

Question 6

which plasmodium is most lethal in humans?

Answer 6

falciparum

Question 7

malaria: who are at high risk of severe infection?

Answer 7

children <5
pregnant women
patients with HIV/AIDS
travellers with no prior infection

Question 8

sickle cell anemia protects against which plasmodium?

why is this?

Answer 8

vivax

vivax needs ‘Duffy receptor’ to enter RBCs. sickle cell anemia patient don’t have this receptor

Question 9

why do thalassemia and G6DP deficiency protect against malaria?

Answer 9

infected RBC’s die more easily because of oxidative stress

Question 10

in which stage is the plasmodium inside the mosquito’s saliva?

Answer 10

stage of development (sporozoite)

Question 11

malaria: how does the mosquito transfer the sporozoites into the bloodstream (via which fluid)?

Answer 11

via saliva

Question 12

once entered into the bloodstream, where do sporozoites (plasmodium in developmental stages) head first? which organ?

what do they do there?

Answer 12

liver, replicate

Question 12

malaria: what happens in the first 2 weeks after infection?

where are the plasmodium sporozoites and what do they do?

Answer 12

liver, multiply (host cells die), mature (into merozoites)

=> exoerythrocytic phase, asymptomatic

(except vivax and ovale -> they do into dormant phase for months-year)

Question 13

malaria: are the first 2 weeks symptomatic or asymptomatic?

Answer 13

asymptomatic

(plasmodium multiply in the liver, not in RBCs)

Question 14

how do you call the first 2 weeks of malaria infection?

Answer 14

exoerythrocytic phase

Question 15

malaria: what happens 2 weeks after infection?

Answer 15

merozoites enter into the bloodstream, start to invade RBCs

=> erythrocytic phase

Question 16

what is the erythrocytic phase of malaria? what happens during this phase? how long does it last?

Answer 16

2 weeks after infection, merozoites enter RBCs: multiply, transformational changes

2-3 days

Question 17

what are the 3 stages of erythrocytic phase?

Answer 17

1. early trophozoid -> tiny ring
2. late trophozoid -> bigger ring
3. schizont (grows by digesting Hb & leaving behind hemozoin) -> brown dot => replicate phase!

Question 18

what is the 3rd stage of the erythrocytic phase? why is this important?

(p. falciporum)

Answer 18

replicate phase

schizonts undergo mitosis, differentiate into lots of merozoites

RBCs breaks and merozoites gets released into the blood

Question 19

summarize the stages/cycle of the erythrocytic phase: start with merozoites

Answer 19

meroziotes invade RBC -> early throphozoid -> late throphozid -> schizont -> ruptured schizont -> meroziotes get released

Question 20

what is the incubation time of p. falciporum?

Answer 20

few days

Question 21

what is the incubation time of p. malariae?

Answer 21

few weeks

Question 22

malaria: what causes the short bursts of fever?

Answer 22

release of inflammatory cytokines into blood (such as tnf-a)

corresponds to rupture of RBC’s (schizont replicate/differentiate into merozoites -> released into bloodstream)

Question 23

how often does a quartan fever happen?

Answer 23

every 72h (3 days)

Question 24

how often does a tertian fever happen?

Answer 24

every 48h

Question 25

p. malariae: causes how often fever?

Answer 25

every 72h (quartan fever)

Question 26

p.vivax&ovale: causes how often fever?

Answer 26

every 48h (tertian fever)

Question 27

quartan fever: which plasmodium?

Answer 27

malariae

Question 28

terian fever: which plasmodium? (2)

Answer 28

vivax, ovale

Question 29

p. falciporum: how often fever?

Answer 29

every 24-48h (malignant tertian fever)

Question 30

p. knowlesi: how often fever?

Answer 30

24h

Question 31

every 24-48h (malignant tertian fever) which plasmodium?

Answer 31

falciporum

Question 32

24h cycle: which plasmodium?

Answer 32

p. knowlesi

Question 33

malaria: which symptoms does the hemolytic anemia cause?

Answer 33

fatigue, headaches, jaundice, splenomegaly

Question 34

which plasmodium causes the worst infections? why is this?

Answer 34

p. falciporum infected RBCs are not destroyed by the spleen, because of a sticky protein coating (look like little bumps) made by the p. falciporum -> also makes the cells clump together, blocks blood flow -> organ failure

Question 35

what causes organ failure in p. falciporum infection?

Answer 35

p. falciporum generates a sticky protein -> RBCs clump together -> blood flow blocked to vital organs (sepsis like clinical picture)

Question 36

what are the symptoms of cerebral malaria?

Answer 36

alter mental status seizures coma

Question 37

what are the symptoms of bilious malaria? (blood flow blocked to liver)

Answer 37

vomiting diarrhea jaundice liver failure

Question 38

how do you diagnose malaria?

Answer 38

thick blood smear: parasites in RBCs thin blood smear: plasmodium species

Question 39

why is it important to know the percentage of infected RBCs in malaria?

Answer 39

>5% can have worse outcomes

Question 40

what are common lab findings in malaria?

Answer 40

- thrombocytopenia - elevated lactate dehydrogenase (LDH) from hemolysis - normochromic & normocytic anemia (normal color and size) -> (LDH indicates tissue damage)

Question 41

malaria: what does suppressive/preventive treatment do? who is it given to?

Answer 41

kill sporozoite before entering the hepatocyte given to travellers

Question 42

how does the therapeutic treatment of malaria work? when is it given?

Answer 42

eliminating meroizites in the erythrocytic phase. given during active infection

Question 43

what is the most common antimalarial drug for uncomplicated malaria? (if no resistance)

Answer 43

Chloroquine => preferred treatment for any parasite that is sensitive to the drug some parts of the world highly resistant

Question 44

what is the most common drug for uncomplicated malaria? (in chloroquine resistant areas)

Answer 44

Artemisinin-based combination therapies (ACTs), such as Coartem

Question 45

what does malaria treatment depened on?

Answer 45

complicated/uncomplicated, pregnancy status, resistancy, plasmodium species

Question 46

recurrent malaria: causes? (3)

Answer 46

- recrudescence: infection not cleared - relapse: RBCs cleared, but not liver - reinfection: single infection does not confer immunity, but acquired ability to tolerate infection

Question 47

does a single malaria infection confer immunity?

Answer 47

no but an acquired ability to tolerate infection

Question 48

malaria prevention measurements?

Answer 48

full body clothing mosquito net insecticide spray no stagnant collections of water