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MSRA Tropical Medicine Questions: Mastering Malaria, Dengue, and Vaccine

Updated: Jul 6

1. Malaria Prophylaxis

A 30-year-old man is travelling to Ghana for 2 weeks. He has no significant past medical history. Which is the most appropriate malaria prophylaxis regimen?

Choose the correct answer

  • A) Chloroquine alone

  • B) Atovaquone-proguanil

  • C) Primaquine

  • D) No prophylaxis needed

Answer: B) Atovaquone-proguanil Explanation: Ghana has chloroquine-resistant P. falciparum malaria. Atovaquone-proguanil is well-tolerated, started 1 day before travel, daily during stay, and 1 week after return.



2. A traveller returns from Thailand with fever, severe headache, retro-orbital pain, and myalgia. Platelets are low. Which is the most likely diagnosis?

Choose the correct answer

  • A) Malaria

  • B) Typhoid fever

  • C) Dengue fever

  • D) Leptospirosis

Answer: C) Dengue fever Explanation: Retro-orbital pain + low platelets + travel to SE Asia are classic for dengue.



3. Cerebral Malaria

Which of the following is first-line treatment for cerebral malaria?

Choose the correct answer

  • A) Oral chloroquine

  • B) IV artesunate

  • C) IV ceftriaxone

  • D) Oral doxycycline

Answer: B) IV artesunate Explanation: Cerebral malaria = medical emergency; artesunate is first-line for severe falciparum malaria.



  1. A 25-year-old woman is travelling to Kenya. Which vaccine is mandatory for entry into some African countries?

Choose the correct answer

  • A) Japanese encephalitis

  • B) Rabies

  • C) Typhoid

  • D) Yellow fever

Answer: D) Yellow fever Explanation: Many African countries require yellow fever vaccination certificate for entry.



5. Malaria Relapse

Which Plasmodium species can cause relapsing malaria months to years after initial infection?

Choose the correct answer

  • A) P. falciparum

  • B) P. malariae

  • C) P. knowlesi

  • D) P. vivax

Answer: D) P. vivax

 Explanation: P. vivax and P. ovale have hypnozoites (dormant liver stages) causing relapse.



6. A 28-year-old woman returns from Nigeria with fever, headache, confusion, and a Glasgow Coma Scale of 9. What is the most likely diagnosis?

Choose the correct answer

  • A) Dengue fever

  • B) Typhoid fever

  • C) Cerebral malaria

  • D) Meningococcal meningitis

Answer: C) Cerebral malaria

 Explanation: Fever + confusion/coma in a traveller from sub-Saharan Africa = cerebral malaria (P. falciparum) until proven otherwise.



7. Japanese Encephalitis Vaccine

Which of the following travel situations most warrants Japanese encephalitis vaccination?

Choose the correct answer

  • A) 2-week city holiday in Singapore

  • B) 5-day business trip to Tokyo

  • C) 6-month rural agricultural work in Vietnam

  • D) 1-week resort stay in Thailand

Answer: C) 6-month rural agricultural work in Vietnam

 Explanation: Japanese encephalitis vaccine is recommended for long stays (>1 month) in rural Asia or high exposure occupations.



8. Which side effect is most commonly associated with Mefloquine prophylaxis?

Choose the correct answer

  • A) Severe photosensitivity

  • B) Neuropsychiatric symptoms vivid dreams, anxiety, low mood

  • C) Hemolytic anemia in G6PD deficiency

  • D) Ototoxicity

Answer: B) Neuropsychiatric symptoms Explanation: Mefloquine can cause anxiety, vivid dreams, depression, and is contraindicated in those with mental health disorders.



9. Which statement about typhoid vaccination is correct?

Choose the correct answer

  • A) Provides lifelong immunity

  • B) Available only as an oral vaccine

  • C) Recommended for all travel to Europe

  • D) Booster needed every 3 years for ongoing risk

Answer: D) Booster needed every 3 years for ongoing risk

 Explanation: Typhoid vaccine (oral or injectable) provides ~3 years protection; boosters are needed for ongoing risk.



10. Which of the following is a warning sign of progression to severe dengue (DHF/DSS)?

Choose the correct answer

  • A) Low-grade fever resolving by day 2

  • B) Increased hematocrit with falling platelets

  • C) Itchy maculopapular rash

  • D) Retro-orbital pain alone

Answer: B) Increased hematocrit with falling platelets Explanation: Rising hematocrit + falling platelets = plasma leakage, a key marker for severe dengue.



11. Which Plasmodium species can cause relapsing malaria due to dormant liver stages (hypnozoites)?

Choose the correct answer

  • A) P. falciparum

  • B) P. malariae

  • C) P. vivax

  • D) P. knowlesi

Answer: C) P. vivax

 Explanation: P. vivax (and P. ovale) form hypnozoites causing relapses months to years later



12. Which of the following is not a feature of severe malaria?

Choose the correct answer

  • A) Hypoglycemia

  • B) Hemoglobinuria (blackwater fever)

  • C) Severe anemia

  • D) Erythema migrans

Answer: D) Erythema migrans

 Explanation: Erythema migrans is the rash of Lyme disease, not malaria.



13. What is blackwater fever most accurately described as?

Choose the correct answer

  • A) Dark urine due to myoglobinuria

  • B) Hemoglobinuria due to massive intravascular hemolysis

  • C) Hematuria due to kidney infection

  • D) Jaundice due to hepatitis co-infection

Answer: B) Hemoglobinuria due to massive intravascular hemolysis

 Explanation: Blackwater fever = dark brown/black urine due to hemoglobin from RBC destruction (falciparum malaria).



14. For how long should doxycycline be continued after leaving a malaria-endemic area?

Choose the correct answer

  • A) Stop immediately after leaving

  • B) 1 day

  • C) 1 week

  • D) 2 weeks

Answer: E) 4 weeks

Explanation: Doxycycline is continued daily for 4 weeks after leaving endemic areas to cover late liver stages maturing into blood forms.



15. Which is the first-line treatment for severe P. falciparum malaria in adults?

Choose the correct answer

  • A) Oral chloroquine

  • B) IV artesunate

  • C) Oral atovaquone-proguanil

  • D) IV ceftriaxone

 Answer: B) IV artesunate

 Explanation: IV artesunate is first-line for severe malaria; IV quinine is alternative if artesunate unavailable.



16. Which is the gold standard for malaria diagnosis?

Choose the correct answer

  • A) Rapid antigen test

  • B) Thick and thin blood films

  • C) PCR assay

  • D) Clinical presentation only

Answer: B) Thick and thin blood films

 Explanation: Microscopy with thick and thin films confirms malaria species and parasite density.



17. Which complication is associated with P. malariae infection?

Choose the correct answer

  • A) Nephrotic syndrome

  • B) Cerebral malaria

  • C) Relapsing fever

  • D) Severe anemia

Answer: A) Nephrotic syndrome

 Explanation: P. malariae can cause chronic immune complex-mediated glomerulonephritis → nephrotic syndrome.


🔑 Tips for MSRA Infectious Disease / Travel Medicine

  • Always know malaria prophylaxis regimens and durations

  • Yellow fever vaccine requirements

  • Cerebral malaria = IV artesunate

  • Dengue = retro-orbital pain + thrombocytopenia

  • Know which malaria species relapse

  • P. vivax/ovale = relapse (hypnozoites)

  • P. falciparum = severe complications (cerebral, ARDS, hypoglycemia)

  • Blackwater fever = hemoglobinuria

  • IV artesunate is first-line for severe malaria

  • Thick & thin films = gold standard diagnosis

  • Doxycycline prophylaxis = continue 4 weeks after return

  • Cerebral malaria = confusion, coma, falciparum malaria

  • Mefloquine = neuropsychiatric side effects

  • Japanese Encephalitis vaccine = rural Asia, >1 month stay

  • Typhoid vaccine = booster every 3 years

  • Severe dengue warning = plasma leakage signs

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