MCQs in Parasitology (11-20): Malaria with Answers
MCQs in Parasitology (11-20): Malaria with Answers
You can try these ten MCQs, the answer with explanations is given at the end of this post. First try each questions yourself; and then only see the answer with explanation and reflect on the differences.
Malaria Practice Questions (11–20)
11. Which is the infective form of the malaria parasite?
a. Oocyst b. Sporozoite c. Bradyzoite d. Tachyzoite
12. Trophozoites, schizonts, and gametocytes of all the malarial parasites are seen in the peripheral blood smear except:
a. P. falciparum b. P. malariae c. P. ovale d. P. vivax
13. Blackwater fever is a special manifestation of malaria caused by:
a. P. falciparum b. P. malariae c. P. ovale d. P. vivax
14. Which Plasmodium species has the longest incubation period?
a. P. falciparum
b. P. malariae
c. P. ovale
d. P. vivax
15. Which of the following statements regarding Plasmodium falciparum are true?
a. Causes more severe disease in pregnancy
b. Is associated with recurrent relapses due to liver hypnozoites
c. Is the only malarial parasite causing greater than 20% parasitemia
d. Infection is typically associated with thrombocytopenia
e. Is the only cause of cerebral malaria
16. Mosquitoes are the vector in which of the following disorders?
a. Onchocerciasis
b. Visceral leishmaniasis
c. African trypanosomiasis
d. Bancroftian filariasis
17. Which of the following statements regarding vivax malaria are true?
a. May be complicated by anemia
b. May be complicated by jaundice
c. In a traveler may present more than six months after exposure
d. Is sensitive to chloroquine
e. May co-exist with falciparum malaria in the same patient
18. Crescent-shaped or banana-shaped gametocytes are seen in infection with:
a. Plasmodium vivax
b. Plasmodium falciparum
c. Plasmodium ovale
d. Plasmodium malariae
19. Match the following dots with the Plasmodium species in which they are prominently seen:
| Dot/Stippling | Species |
|---|---|
| a. Maurer's clefts | I. P. vivax |
| b. Schüffner's dots | II. P. falciparum |
| c. Ziemann's stippling | III. P. ovale |
| d. James' dots | IV. P. malariae |
a. a-I, b-II, c-III, d-IV
b. a-II, b-I, c-IV, d-III
c. a-III, b-II, c-IV, d-I
d. a-II, b-I, c-IV, d-III
20. A situation where persistent blood-stage parasites that were never fully eliminated begin to multiply again, causing renewed clinical symptoms, is called:
a. Latency
b. Re-infection
c. Relapse
d. Recrudescence
Answer Key and Explanations
11. Correct Answer: b — Sporozoite
During a blood meal, a malaria-infected female Anopheles mosquito inoculates sporozoites from its salivary glands into the human host. These sporozoites travel through the bloodstream to infect liver cells (hepatocytes), initiating the pre-erythrocytic schizogony stage.
12. Correct Answer: a — P. falciparum
In P. falciparum infections, mature trophozoites and schizonts express surface proteins (like PfEMP1) that cause infected RBCs to adhere to capillary walls in internal organs. Consequently, only early ring forms and crescent-shaped gametocytes are typically found in a peripheral blood smear.
13. Correct Answer: a — P. falciparum
Blackwater fever is characterized by sudden, massive intravascular hemolysis leading to severe hemoglobinuria. The dark, hemoglobin-rich urine gives the syndrome its name. It is strongly associated with severe P. falciparum infections, often exacerbated by irregular quinine use, and can trigger acute renal failure.
14. Correct Answer: b — P. malariae
P. malariae has the slowest development cycle, with an incubation period typically ranging from 18 to 40 days or longer. It causes benign quartan malaria with fever paroxysms every 72 hours (every fourth day), compared to the 48-hour tertian cycles of P. vivax and P. ovale.
15. Correct Answer: a, c, and d
- a — True: Pregnant women have lowered immunity and high placental sequestration of P. falciparum, making infections highly dangerous.
- b — False: P. falciparum does not produce dormant liver hypnozoites; that is unique to P. vivax and P. ovale.
- c — True: P. falciparum can invade RBCs of all ages, allowing parasitemia to exceed 20%. Other species are limited to young or old cells, keeping parasitemia below 2–5%.
- d — True: Thrombocytopenia is a frequent hematological finding in falciparum malaria.
- e — False: While P. falciparum is overwhelmingly responsible, rare cases of cerebral malaria have been documented in severe P. vivax infections.
16. Correct Answer: d — Bancroftian filariasis
Bancroftian filariasis is transmitted by mosquitoes (chiefly Culex, Anopheles, and Aedes). The other disorders have different vectors: Onchocerciasis by the Blackfly (Simulium), Visceral leishmaniasis by the Sandfly (Phlebotomus), and African trypanosomiasis by the Tsetse fly (Glossina).
17. Correct Answer: All of the above — a, b, c, d, and e
- a & b: Vivax malaria destroys red blood cells and affects liver function, frequently leading to hemolytic anemia and jaundice.
- c: P. vivax forms dormant hypnozoites in the liver; a returning traveler can present with symptoms more than 6 months after exposure.
- d: Classic P. vivax remains generally sensitive to chloroquine for the blood-stage parasite.
- e: Mixed co-infections of P. vivax and P. falciparum are commonly seen in endemic areas.
18. Correct Answer: b — Plasmodium falciparum
P. falciparum produces distinct elongated, crescent-shaped gametocytes that distort the host red blood cell — a highly diagnostic morphological feature. The gametocytes of P. vivax, P. ovale, and P. malariae remain spherical or rounded.
19. Correct Answer: b — a-II, b-I, c-IV, d-III
- Maurer's clefts → P. falciparum (coarse granulations)
- Schüffner's dots → P. vivax (fine surface invaginations)
- Ziemann's stippling → P. malariae (fine, faint dots requiring prolonged staining)
- James' dots → P. ovale (similar to Schüffner's but larger and darker)
20. Correct Answer: d — Recrudescence
Recrudescence is the renewal of symptoms from persistent blood-stage parasites that dropped below detectable levels but were never fully eliminated. This differs from Relapse, which occurs when dormant liver hypnozoites (seen only in P. vivax and P. ovale) reactivate to initiate a new blood-stage infection.