A 28-year-old man from Vietnam develops dengue fever. He has a secondary dengue infection (positive IgG in acute phase). What laboratory finding disti...

Question

A 28-year-old man from Vietnam develops dengue fever. He has a secondary dengue infection (positive IgG in acute phase). What laboratory finding distinguishes secondary from primary dengue infection?

Accepted Answer

In secondary dengue, IgG antibodies are detectable in the acute phase (within the first 7 days of illness), reflecting an anamnestic response from prior heterotypic infection; in primary dengue, IgG appears later (after day 7-10)

Answer

Secondary infection shows lower NS1 levels

Answer

Primary and secondary dengue are identical serologically

Answer

Only PCR can distinguish them

Answer

Secondary infection always has higher platelet counts

uk-dtmh MCQ (SBA): Primary vs Secondary Dengue Serology

A 28-year-old man from Vietnam develops dengue fever. He has a secondary dengue infection (positive IgG in acute phase). What laboratory finding distinguishes secondary from primary dengue infection?