Malaria

Question 1

What type of pathogen is malaria?

Answer 1

Protozoan parasite - acicomplexa

Plasmodium spp.

Question 2

What is the cause of malaria?

Answer 2

Plasmodium spp.

Question 3

What is the transmission route of malaria?

Answer 3

Vector - bite of female anopheles mosquito

Question 4

What are the signs/symptoms of malaria?

Answer 4

Spiking fever, chills, vomiting, severe headache

Question 5

What additional symptoms does P. falciparum cause?

Answer 5

Severe anaemia, kidney and liver damage

Question 6

How many carriers are there of malaria each year?

Answer 6

150-300 million

Question 7

How many new cases of malaria each year?

Answer 7

200 million

Question 8

How many people in the world are at risk of malaria?

Answer 8

3.2 billion

Almost half the worlds population

Question 9

Where do a majority of malaria deaths occur?

Answer 9

Sub-Saharan Africa

91% of all deaths

Question 10

How many species of Plasmodium are there?

Answer 10

> 100

Question 11

Who does malaria infect?

Answer 11

humans, monkeys, rodents, birds, lizards

Question 12

How many Anopheles species are there and how many transmit malaria?

Answer 12

430

30-40 transmit malaria

Question 13

What is the lifespan of the Anopheles mosquito?

Answer 13

2-3 weeks

Question 14

When does Anopheles breeding increase?

Answer 14

Rainy season

Question 15

How many eggs does the Anopheles mosquito lay and how often?

Answer 15

30-150 eggs every 2-3 days and needs blood to nourish eggs

Question 16

When does the female Anopheles mosquito bite?

Answer 16

Late evening - peaking 12am to early morning

Question 17

How does the Anopheles mosquito penetrate the skin?

Answer 17

Through specialised proboscis

Question 18

Where do the Anopheles mosquitos lay their eggs?

Answer 18

In natural water collections

Question 19

How far can the Anopheles mosquito fly?

Answer 19

several kilometers

Question 20

Where can the Anopheles mosquito shelter?

Answer 20

Motor vehicles, ships and aircraft

Question 21

What are the 5 species of Plasmodium that infect humans?

Answer 21

P. falciparum - most deadly and severe, 50% mortality
P. vivax - high morbidity - most common, widespread
P. ovale
P. malariae
P. knowlesi

Question 22

What is the most common cause of malaria?

Answer 22

P. vivax

Question 23

What is the most deadly cause of malaria?

Answer 23

P. falciparum

Question 24

What are the 2 hosts of malaria?

Answer 24

Definitive host: Anopheles mosquito

Intermediate host: humans

Question 25

What is meant by definitive host?

Answer 25

Host where sexual reproduction occurs

Question 26

What is meant by intermediate host?

Answer 26

Host where the organism only reproduces asexually

Question 27

What is the lifecycle of malaria in the definitive host?

Answer 27

Gametes -> ookinete -> oocyst -> sporozoite

Question 28

What is the lifecycle of malaria in intermediate host?

Answer 28

Liver: sporozoite -> hypnozoite -> merozoite Blood: merozoite -> ring -> trophozoite -> schizont -> merozoite -> gametocyte

Question 29

What are the sexual forms of malaria?

Answer 29

Gametocyte Gamete Ookinete Oocyst

Question 30

What are the intracellular forms of malaria?

Answer 30

``` Hypnozoites (liver) Ring (RBC) Trophozoite (RBC) Schizont (liver, RBC) Gametocyte ```

Question 31

What is the dominant form of malaria?

Answer 31

Hypnozoite

Question 32

What is the lifecycle of the malaria parasite? | Start with the Anopheles mosquito taking a blood meal and ingesting gametocytes

Answer 32

MOSQUITO - SPOROGENIC CYCLE 1. Anopheles mosquito takes a blood meal and ingests gametocytes 2. These gametocytes form a gamete 3. Gamete becomes motile ookinete 4. Ookinete burrows into gut to form oocyst 5. Oocyst becomes sporozoites which burst out and travel to salivary glands 6. When Anopheles mosquito takes a blood meal, sporozoites are injected into human HUMAN - HEPATOCYTIC CYCLE 7. Sporozoites migrate to liver (40-60 minutes) invade hepatocytes via Kupffer cells 8. May undergo asexual reproduction (schizony) to form schizont (some sporozoites may remain dormant as hypnozoites) 9. Schizont ruptures releasing merozoites into blood HUMAN - ERYTHROCYTIC CYCLE 10. Merozoites invade red blood cells 11. Form a ring 12. RIng can become a trophozoite 13. Trophozoite can form a schizont through asexual reproduction 14. Schizont ruptures, releasing merozoites that invade other red blood cells 15. Once ring is formed, it can also become a gametocyte 16. Gametocyte can be taken up by Anopheles mosquito when they take a blood meal

Question 33

How long does the whole malaria lifecycle take?

Answer 33

8-35 days

Question 34

How long does the pre-erythrocytic stage take?

Answer 34

7 days

Question 35

Are symptoms present in the pre-erythrocytic stage?

Answer 35

No

Question 36

In which species of Plasmodium can hypnozoites form?

Answer 36

P. vivax and P. ovale | NOT P. falciparum

Question 37

What is the duration of replicative cycle in the erythrocytic cycle in the different species of Plasmodium?

Answer 37

P. falciparum, P, vivax, P. ovale - 48 hours P. malariae - 72 hours P. knowlesi - 24 hours