Malaria

Question 1

Malaria – Genus Plasmodium:
Vector

Answer 1

Anopheles mosquito (mosquito = definitive host)

Question 2

Malaria – Genus Plasmodium:
Humans

Answer 2

intermediate host (parasite multiplies asexually in RBCs)

Question 3

Plasmodium falciparum

Answer 3

RBCs infected: All ages → causes high parasitemia

Inclusions: Banana-shaped gametocytes

Disease: Most severe, can be fatal (cerebral malaria, organ failure)

Sickle Cell Trait: Strong protection against severe disease

Question 4

Plasmodium vivax

Answer 4

RBCs infected: Young RBCs (reticulocytes)

Inclusions: Schüffner’s dots

Disease: Can become latent (liver hypnozoites) → relapses

Special Note: Requires Duffy antigen to enter RBCs; Duffy-negative individuals (many in Africa) are protected

Question 5

Plasmodium ovale

Answer 5

RBCs infected: Young RBCs

Inclusions: Schüffner’s dots, oval-shaped RBCs

Disease: Latent (liver hypnozoites) → relapses

Severity: Mild to moderate

Question 6

Plasmodium malariae

Answer 6

RBCs infected: Old RBCs

Inclusions: Band-form trophozoites

Disease: Chronic, slow infection

May lead to nephrotic syndrome

Question 7

Plasmodium knowlesi

Answer 7

Zoonotic (monkeys → humans)

Can cause severe infection similar to falciparum

Question 8

Sickle Cell Trait Protection

Answer 8

Sickle cell trait (HbAS) protects against P. falciparum infection and severity.

Does not significantly protect against vivax or malariae.