The views represented in this paper are solely those of the authors and not the representative institution. Use of tradenames and products is not an endorsement.
Norwalk virus: How infectious is it?†
Article first published online: 12 JUN 2008
Copyright © 2008 Wiley-Liss, Inc.
Journal of Medical Virology
Volume 80, Issue 8, pages 1468–1476, August 2008
How to Cite
Teunis, P. F.M., Moe, C. L., Liu, P., E. Miller, S., Lindesmith, L., Baric, R. S., Le Pendu, J. and Calderon, R. L. (2008), Norwalk virus: How infectious is it?. J. Med. Virol., 80: 1468–1476. doi: 10.1002/jmv.21237
- Issue published online: 12 JUN 2008
- Article first published online: 12 JUN 2008
- Manuscript Accepted: 22 APR 2008
- U.S. Environmental protection Agency (cooperative agreement). Grant Number: R-82936501
- USEPA STAR. Grant Number: R-826139
- PHS. Grant Number: RR00046
- NIAID. Grant Number: 5R01 A105U351-03
- National Institutes of Health
- European Commission (Sixth Framework Programme). Grant Number: SSP22-CT-2004-502084
- primary inoculum;
- secondary inoculum;
- viral gastroenteritis;
- dose response;
- virus aggregation
Noroviruses are major agents of viral gastroenteritis worldwide. The infectivity of Norwalk virus, the prototype norovirus, has been studied in susceptible human volunteers. A new variant of the hit theory model of microbial infection was developed to estimate the variation in Norwalk virus infectivity, as well as the degree of virus aggregation, consistent with independent (electron microscopic) observations. Explicit modeling of viral aggregation allows us to express virus infectivity per single infectious unit (particle). Comparison of a primary and a secondary inoculum showed that passage through a human host does not change Norwalk virus infectivity. We estimate the average probability of infection for a single Norwalk virus particle to be close to 0.5, exceeding that reported for any other virus studied to date. Infected subjects had a dose-dependent probability of becoming ill, ranging from 0.1 (at a dose of 103 NV genomes) to 0.7 (at 108 virus genomes). A norovirus dose response model is important for understanding its transmission and essential for development of a quantitative risk model. Norwalk virus is a valuable model system to study virulence because genetic factors are known for both complete and partial protection; the latter can be quantitatively described as heterogeneity in dose response models. J. Med. Virol. 80:1468–1476, 2008. © 2008 Wiley-Liss, Inc.