An outbreak of acute hepatitis A is traced to a restaurant food handler who prepared salads during the week before he became icteric. At what point in the course of hepatitis A virus infection is an individual maximally infectious?
- A Only during relapse, if a biphasic course occurs
- B During the icteric phase, when serum aminotransferases are highest
- C During the two weeks before the onset of symptoms, when viral shedding in stool peaks ✓
- D Equally throughout the illness, until anti-HAV IgG appears
Correct answer: C. During the two weeks before the onset of symptoms, when viral shedding in stool peaks
Explanation
HAV is shed in highest concentration in feces during the late incubation period and prodrome, roughly two weeks before jaundice, and viremia also peaks at this time. By the time jaundice and peak transaminases appear, fecal shedding is already falling sharply, which is why the icteric patient is less contagious than the asymptomatic pre-icteric one. This explains outbreaks seeded by apparently well food handlers.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.