Malaria

Question 1

What’s the limiting factor for the transmission of malaria?

Answer 1

Transmitted by mosquitoes, no person-to-person transmission + there is an incubation/replication period within mosquito. 2 weeks before it can infect humans

Question 2

What are the two major malaria species causing human disease?

Answer 2

P. falciparum

P. vivax

Question 3

T/F P. vivax poses huge health burden in Africa

Answer 3

False, sickle cell provides immunity against vivax in particular

Question 4

Which Plasmodium species causes zoonotic infection

Answer 4

P. knowlesi

Question 5

What are the two forms of malaria parasite?

Answer 5

Merozoites

Sporozoties

Question 6

What’s the pathophysiology of malaria infection?

Answer 6

mosquito injects parasite. Sporozoites parasite invades liver within 1-2 hours, followed by 7-10 days incubation. Merozoites eventually burst out of hepatocytes and enter blood stage infection

Question 7

How does malaria cause metabolic acidosis

Answer 7

malaria induced haemolysis, leading to reduced tissue perfusion, and metabolic acidosis, which will then cause respiratory distress

Question 8

What is the treatment for severe malaria?

Answer 8

IV infusion of anti-malarial artemisinin + supportive treatment

Question 9

What are the consequences of unrestricted replication of malaria in blood?

Answer 9

accumulation of parasites in vital organs
inflammatory responses
RBC destruction

Question 10

T/F P. vivax can be completely cleared from blood

Answer 10

True

P. falciparum is more challenging to treat

Question 11

T/F We cannot generate immunity against malaria

Answer 11

False, but only after many episodes

Question 12

What are the three main types of malaria immunity?

Answer 12

Immunity against severe malaria, any malaria, or malaria in pregnancy

Question 13

What are some reasons for the slow development of immunity

Answer 13

antigenic diversity

host inadequate response + poor memory of immunity

Question 14

Which cells are the targets of acquired malarial immunity?

Answer 14

sporozoites + merozoites

infected hepatocytes + RBC

Question 15

T/F immunity against infected hepatocytes is relatively effective

Answer 15

False, because of the low parasite load and short duration of infection, the immunity is not very good

Question 16

Is RBC a good target of malarial immunity?

Answer 16

Yes, but in the right balance. CD4 immunity is not viable because RBCs lack MHC molecules, so immunity relies on the right amount of cytokines

Enough = protection
Too much = severe disease

Question 17

How do we generate antibodies to merozoites?

Answer 17

infected RBCs will display proteins that activate complement system/opsonisation and enhances phagocytosis

However, passive transfer of antibodies needs to occur for this protection

Question 18

What’s the main issue associated with immunity against merozoities?

Answer 18

too many proteins on the surface for specific response