Malaria

Question 1

Definition

Answer 1

DEFINITION: infection with protozoan Plasmodium

FIVE types of Plasmodium:

Plasmodium falciparum - MOST SERIOUS

Plasmodium vivax

Plasmodium ovale

Plasmodium malariae

Plasmodium knowlesi

Question 2

Causes

Answer 2

Transmitted by the bite of the female Anopheles mosquito

The protozoa grow in red blood cells

Life Cycle

• Injection of sporozoites into the blood stream by mosquito
• Invasion and replication in hepatocytes
• Parasites reinvade the blood and enter red blood cells
• They replicate within red blood cells and develop ring forms
• Red blood cells rupture and release merozoites, which reinfect other red blood cells
• Gametocytes are taken up when another mosquito feeds, and develop into sporozoites in the gut of the mosquito
• They then move to the salivary gland of the mosquito to be transmitted with the next bite

Some populations have innate immunity to malaria:

• Sickle cell trait
• G6PD deficiency
• Pyruvate kinase deficiency
• Thalassemia

Question 3

Epidemiology

Answer 3

Endemic in the tropics

250 million people worldwide

Question 4

Symptoms

Answer 4

Feverish traveller (incubation period can be up to 1 year)

Symptoms are CYCLICAL:

• High fever
• Flu-like symptoms
• Severe sweating
• Shivering cold/rigors

NOTE: the interval between cycles of symptoms are slightly different in different types of malaria

Cerebral Malaria Symptoms:

• Headache
• Disorientation
• Coma

Question 5

Signs

Answer 5

Pyrexia

Anaemia (haemolytic)

Hepatosplenomegaly

Question 6

Investigations

Answer 6

Thick/Thin Blood Films

• Thick for quantifying
• Thin for identifying type of malaria

Bloods

• FBC - haemolytic picture
• U&Es
• LFTs
• ABG

Urinalysis -check for blood or protein