Which of the following dengue sequential serotypes infection are associated with maximum risk of dengue hemmorhagic fever?
**Core Concept:** Dengue is an arboviral infection caused by the dengue virus, a member of the Flaviviridae family. Dengue infection follows a sequential pattern involving four serotypes (DENV-1 to DENV-4).
**Why the Correct Answer is Right:** The correct answer is DENV-2, as it is associated with the highest risk of severe dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). DHF/DSS typically develops in individuals infected with any serotype for the first time (primary infection).
DENV-2 is one of the four serotypes that can lead to secondary infections with increased severity due to antibody-dependent enhancement (ADE). ADE occurs when non-neutralizing antibodies from a previous infection with one serotype bind to the virus and enhance virus entry into a target cell, increasing the risk of severe disease.
**Why Each Wrong Option is Incorrect:**
A. DENV-1: Although DENV-1 can cause DHF/DSS, it is less commonly associated with severe disease compared to DENV-2.
B. DENV-3: Similar to DENV-1, DENV-3 is less commonly associated with severe DHF/DSS compared to DENV-2.
C. DENV-4: DENV-4 is less commonly associated with severe DHF/DSS compared to DENV-2.
D. All serotypes can cause DHF/DSS: While this statement is true, the severity and risk of DHF/DSS varies among serotypes. DENV-2 is the most severe.
**Clinical Pearl:** In areas of endemicity, understanding the serotype-specific risks is crucial for clinical decision-making and patient management strategies.
**Correct Answer:** DENV-2
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**Core Concept:** Dengue fever is caused by infection with one of the four dengue virus serotypes (DENV-1, DENV-2, DENV-3, and DENV-4) and is transmitted by Aedes mosquitoes.
**Why the Correct Answer is Right:** DENV-2 is associated with higher risk of severe dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) compared to other serotypes. This is due to the mechanism of antibody-dependent enhancement (ADE), where non-neutralizing antibodies from a previous infection with one serotype increase the risk of severe disease upon subsequent infection with a different serotype, particularly DENV-2.
**Why Each Wrong Option is Incorrect:**
A. DENV-1: Although DENV-1 can cause DHF/DSS, it is less commonly associated with severe disease compared to DENV-2.
B. DENV-3: Similar to DENV-1, DENV-3 is less commonly associated with severe DHF/DSS compared to DENV-2.
C. DENV-4: DENV-4 is less commonly associated with severe DHF/DSS compared to DENV-2.
D. All ser