8 - Malaria

Question 1

Where is malaria currently prevalent?

Answer 1

Africa (predominantly central), south america and south east Asia

Question 2

Where do most deaths from malaria occur

Answer 2

Africa

Question 3

How many people are at high risk of malaria?

Answer 3

> 1 billion

Question 4

Name the five species of plasmodium that infects humans

Answer 4

Plasmodium falciparum, plasmodium vivax, plasmodium malariae, plasmodium ovale and plasmodium knowlesi

Question 5

What is Quotidian Malaria and which species causes it?

Answer 5

A daily fever (fever every 24 hours) caused by plasmodium knowlesi

Question 6

What is tertian malaria and which species cause it?

Answer 6

A fever every 48 hours caused by either falciparum, vivax or ovale

Question 7

What is quartan malaria and what species causes it?

Answer 7

Malaria with a fever every 72 hours caused by plasmodium malariae

Question 8

What is the main way that malaria is transmitted?

Answer 8

By the bite of a female anopheles mosquito

Question 9

Describe 5 other ways that malaria can be transmitted?

Answer 9

1. Introduced malaria - local mosquitoes bite people who acquired malaria abroad and then transmit to local residents
2. Airport malaria - infected mosquitoes are transported via aircraft from an endemic country to a non-endemic country
3. transfusion malaria - malaria acquired via blood transfusion
4. mainline malaria - acquired via sharing needles and syringes
5. congenital malaria - infected mothers transmit the pathogen to their child during pregnancy or during delivery

Question 10

What is a sporozite and what is it’s role in a malaria infection?

Answer 10

A motile spore that is injected into the skin by the mosquito. It then penetrates the blood vessel and enters circulation before it penetrates a hetaptocyte and divides to form merozites

Question 11

What is a schizont?

Answer 11

A structure formed by the a sexual reproduction of a sporozoite that bursts to release meroziotes

Question 12

What is a merozoite?

Answer 12

The form of plasmodium that infects red blood cells

Question 13

What is a trophozoite?

Answer 13

The form of plasmodium that is a single called uncleared mass of protoplasm that modifies the red blood cells in order to require nutrients

Question 14

What is a gametocyte in relation to malaria?

Answer 14

The sexually developed form of a trophocyte

Question 15

What is a zygote in relation to malaria?

Answer 15

A diploid form of plasmodium that is formed by the fusing of a micro-male gamete and a female gamete

Question 16

What is an ookinete in relation to malaria?

Answer 16

A motile form on plasmodium that develops from the zygote that is able to penetrate the intestinal wall of a mosquito

Question 17

What is an oocyst in relation to malaria?

Answer 17

A differentiated form of a ookinete that grow and internally divide to form sporozoites

Question 18

Describe 5 factors that lead to the pathogenesis of malaria?

Answer 18

1. toxins released when schizonts burst stimulate T cells to produce cytokines which cause fever, bone marrow depression and phagocytosis of RBCs
2. anaemia as a result of parasitic growth, reduced erythropoiesis and erythrophagocytosis
3. hypoglycaemia
4. clotting defects
5. immunodepression (increases susceptibility to sepsis)

Question 19

Give 8 clinical feature/ complications of malaria

Answer 19

• periodic fever
• anaemia
• acute respiratory distress
• hypoglycaemia
• enlargement of the liver and spleen
• haemoglobinuria (Hb in urine)
• haemoglobinaemia (Hb in blood plasma)
• capillary blockages

Question 20

How is malaria diagnosed?

Answer 20

Blood smears stained with giemsa

Question 21

What is the main treatment for malaria?

Answer 21

Quinine/chloroquine

Question 22

How does chloroquine work?

Answer 22

It interferes with haemozoin formation

Question 23

How is malaria prevented?

Answer 23

Insecticide treated bed nets