Volume 14, Number 10—October 2008
Research
Norwalk Virus Shedding after Experimental Human Infection
Robert L. Atmar
, Antone R. Opekun, Mark A. Gilger, Mary K. Estes, Sue E. Crawford, Frederick H. Neill, and David Y. Graham
, Antone R. Opekun, Mark A. Gilger, Mary K. Estes, Sue E. Crawford, Frederick H. Neill, and David Y. GrahamTable
Fecal virus shedding among 16 participants inoculated with Norwalk virus*
| Participant no. | Estimated Norwalk virus inoculum dose (RT-PCR units) | First–last study days† postinoculation when symptoms present | First–last study days IMC RT-PCR positive | Day peak virus titer (character of feces) | Peak qRT-PCR virus titer (log10/g) | First–last study days postinoculation when antigen positive |
|---|---|---|---|---|---|---|
| Met clinical definition of gastroenteritis | ||||||
| Had diarrhea and vomiting | ||||||
| 706 | 4,800 | 2 | 2–28‡ | 2 (liquid) | 11.1 | 2–9 |
| 707 | 4,800 | 2–4 | 1–30‡ | 2 (liquid) | 9.5 | 4–8 |
| 710 | 4,800 | 1–2 | 2–30‡ | 5 (solid) | 10.9 | 2–7 |
| 722 | 48 | 2 | 2–48 | 4 (solid) | 11.7 | 2–8 |
| 724 | 4.8 | 2–3 | 2–56 | 3 (solid) | 11.4 | 2–6 |
| Had vomiting only | ||||||
| 701 | 4,800 | 1–2 | 1–29‡ | 4 (solid) | 10.8 | 3–10 |
| 720§ | 48 | 2 | 2–56 | 4 (solid) | 11.5 | 2–9 |
| 721 | 48 | 1–3 | 2–21 | 4 (solid) | 11.7 | 2–10 |
| 723 | 48 | 2 | 1–50 | 4 (solid) | 12.2 | 2–6 |
| 731 | 4.8 | 2–3 | 5–10 | 5 (solid) | 10.0 | None |
| 732 | 4.8 | 2–3 | 2–15 | 3 (solid) | 11.9 | 2–6 |
| Median |
– |
2 |
2–30‡ |
4 (solid) |
11.4 |
2–8 |
| Did not meet clinical definition of gastroenteritis | ||||||
| 703 | 4,800 | 2–3 | 1–32‡ | 2 (solid) | 10.7 | 2–9 |
| 704 | 4,800 | 2–3 | 4–21‡ | 5 (solid) | 9.2 | 5–7 |
| 715§ | 48 | 2–3 | 1–28 | 3 (solid) | 11.7 | 2–5 |
| 716§ | 48 | 2–3 | 1–20 | 4 (unformed) | 10.1 | 3–7 |
| 717 | 48 | 3 | 4–13 | 4 (solid) | 9.3 | None |
| Median | – | 2–3 | 1–21‡ | 4 (solid) | 10.1 | 2–7 |
*RT–PCR, reverse transcription–PCR; IMC, immunomagnetic capture; qRT-PCR, quantitative PCR.
†Study days are reported as calendar days; study day 1 began ≈5–6 h postinoculation.
‡Fecal samples only collected for 30 d postinoculation.
§Watery feces with mass <200 g.
