Malaria 1

Question 1

What are the 5 species of malaria that infect man?

Answer 1

P. falciparum, malariae, vivax, ovale and knowlesi

Question 2

Which species is most common? SE Asia?

Answer 2

P. falciparum; P. vivax

Question 3

Differentiate Unstable malaria from Stable malaria

Answer 3

Unstable: Transmission is less intense and episodic, all ages are vulnerable
Stable: Heavy transmission over millenia, Individuals over age 5 are generally protected

Question 4

Discuss the Plasmodium life cycle

Answer 4

1. Sporozoites injected by female Anopheles mosquito
2. Schizonts develop in hepatocytes for 7-10 days
3. Merozoites invade RBCs
4. Intraerythrocytic trophozoites develop into schizonts in RBCs
5. Gametocytes develop and are ingested by mosquito.

Question 5

Which species can cause relapse?

Answer 5

P. vivax and P. ovale

Question 6

Which species can cause recrudesce?

Answer 6

P. falciparum and P. malariae

Question 7

Discuss thin film diagnosis

Answer 7

RBC morphology is maintained. Able to determine parasite details making it helpful for speciation. Less sensitive than other methods.

Question 8

Discuss thick film diagnosis

Answer 8

RBCs lysed during prep. Difficult to interpret but more sensitive than thin films. (Useful for quick diagnosis)

Question 9

Differentiate the HRP-2 and pLDH dipsticks

Answer 9

HRP-2: Stays positive for up to two weeks following treament.
pLDH: Only positive when there are live parasites in circulation.