Malaria

Question 1

How common are P. vivax infections?

Answer 1

~45% of malaria cases

Question 2

Explain the difference between short-prepatent & long-prepatent sporozoites & how one of these is related to replapse. ( P. vivax)

Answer 2

short prepatent: invade heptocytes develop into metzoites leave hepatocytes & invade RBCs
long prepatent: invade heptocytes develop into metozoites remain in heptocytes = hypnozoites
relapse bc hypnozoites leave liver & invade RBCs

Question 3

Where are Duffy antigens found & why are they significant in P. vivax infection? ( P. vivax)

Answer 3

surface of RBCs

merozoites can only penetrate RBCs with Duffy antigen on surface

Question 4

What people are resistant to vivax malaria?

Answer 4

Duffy negative

Question 5

What are Schnuffner’s dots?

Answer 5

stipplies on RBCs in P. vivax

Question 6

How often do the fevers occur in P. vivax infection?

Answer 6

every 48 hours

Question 7

How common are P. malariae infections?

Answer 7

~7% of cases

Question 8

How often do the fevers occur in P. malariae infection?

Answer 8

every 72 hours

Question 9

What is the band form in P. malariae?

Answer 9

mature ring stage

elongates and bnad forms

Question 10

How does recrudescence differ from relapse? (P. malariae)

Answer 10

sick, recover, sick again
bc of sudden increase in persistant undetected population in blood
can never donate blood again

Question 11

How common are P. ovale infections?

Answer 11

rare

Question 12

How often to the fevers occur in P. ovale?

Answer 12

mild fevers every 48 hrs

Question 13

How did the parasite get its name? (P. ovale)

Answer 13

Mature schizout and RBC are oval shaped

Question 14

How common are P. falciparum infections?

Answer 14

> 50% of all malaria cases

Question 15

What symptoms occur in cerebral malaria?

Answer 15

heaches
coma
high fever (108 degrees F)
convulsions
fatal within 24-72 hrs

Question 16

How does the mechanical hypothesis explain cerebral malaria?

Answer 16

bind to endothelial cells
block capillaries
reduce blood flow
hypoxia

Question 17

How does the humoral hypothesis explain cerebral malaria?

Answer 17

malarial toin stimulates macrophages to release cytokines
stimulate production of nitric oxide
diffuses across BBB & effect synaptic function
similar to general anesthetics & high ethanol concentration

Question 18

What happens in Blackwater fever?

Answer 18

acute massive lysis of RBCs
infected & uninfected
high levels of Hb & hemozoin in blood
urine very dark
kidney failure
autoimmune

Question 19

Why is there a difference in pathology between P. falciparum & the other human Plasmodium species?

Answer 19

P.v. = young RBCs
R.m. = old RBCs
P.o. = young RBCs
P.f. = all

Question 20

How does sickle cell Hb differ from normal Hb?

Answer 20

B chains have one glutamic acid replaced by valine

Question 21

What happens to sickle cell Hb during oxygen stress?

Answer 21

sickle shape

reduce flexibility

Question 22

What is the heterozygote advantage and what can happen to homozygotes?

Answer 22

~60% RBC - normal Hb
~40% RBC - sickle Hb
level of parasitemia is 1%
homozygotes die young from Plasmodium f. infection

Question 23

How does quinine function?

Answer 23

acts on blood stages

Question 24

How does chloroquine function?

Answer 24

blocks heme polymerase

against blood stages

Question 25

How does pyrimethamine function?

Answer 25

against liver stage | inhibits dihydrofolate reductase necessary for folic acid synthesis

Question 26

What adverse events are associated with mefloquine?

Answer 26

adverse CNS effects - | depression, anxiety, paranoia, aggression, seizures, birth defects

Question 27

What drugs are found in ACTs?

Answer 27

Artmenisimin based combination therapies 1. one drug is derivate of artemisinin related to Artmenisia annina (plant) 2. partner drug used in combination (ex: Mefloquine)

Question 28

The derivative of artmenisinin is based on what compound?

Answer 28

Artmenisia annina (plant)

Question 29

How do the derivative & the partner drug differ in ACTs? Why is this difference significant?

Answer 29

The partner drugs use different modes of action to wipeout parasite. THis prevents the development of resistance to the drugs.

Question 30

What is premunition?

Answer 30

resistance to super infection

Question 31

What are children so susceptible to Plasmodium infections?

Answer 31

no longer breastfeeding | immune system is not fully developed

Question 32

What does the RTS,S vaccine stimulate and how does this affect the parasite?

Answer 32

stimulates antibody production & T cell response | parasite doesn't develop in the liver

Question 33

Where was the PfSPZ vaccine developed?

Answer 33

Rockville, MD

Question 34

How is the PfSPZ vaccine produced?

Answer 34

weakened form of sporozoite from salivary glands of irradiated mosquitos are harvested

Question 35

How can mosquitos be controlled?

Answer 35

destruction of breeding sites mosquito predators insecticides bed nets