A traveler returning from South-East Asia presents with high fever, severe myalgia, retro-orbital pain, and a maculopapular rash with islands of sparing. Platelet count is 60,000/μL and tourniquet test is positive. Dengue serology is positive. The vector is:
- A Anopheles mosquito (night-biting)
- B Culex mosquito
- C Aedes aegypti mosquito (day-biting) ✓
- D Phlebotomus sandfly
Correct answer: C. Aedes aegypti mosquito (day-biting)
Explanation
Dengue fever is transmitted by the Aedes aegypti mosquito (and also Aedes albopictus), which bites during daytime, peaking at dawn and dusk. The dengue virus belongs to family Flaviviridae and has 4 serotypes (DENV 1-4). Secondary infection with a heterologous serotype can cause severe dengue (dengue hemorrhagic fever/dengue shock syndrome) through antibody-dependent enhancement, where non-neutralizing antibodies from previous infection facilitate viral entry into macrophages. The rash shows characteristic white islands of sparing in a sea of redness.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.