Norwalk Virus Shedding after Experimental Human Infection

摘要

Noroviruses are the most common cause of viral gas-troenteritis in the United States. To determine the magni-tude and duration of virus shedding in feces, we evaluated persons who had been experimentally infected with Nor-walk virus. Of 16 persons, clinical gastroenteritis (watery diarrhea and/or vomiting) developed in 11; symptomatic illness lasted 1–2 days. Virus shedding was fi rst detected by reverse transcription–PCR (RT-PCR) 18 hours after par-ticipant inoculation and lasted a median of 28 days after inoculation (range 13–56 days). The median peak amount of virus shedding was 95 × 109(range 0.5–1,640 ×109) genomic copies/g feces as measured by quantitative RT-PCR. Virus shedding was fi rst detected by antigen ELISA ≈ 33 hours (median 42 hours) after inoculation and lasted 10 days (median 7 days) after inoculation. Understanding of the relevance of prolonged fecal norovirus excretion must await the development of sensitive methods to measure vi-rus infectivity