This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ozawa, K.
Right arrow Articles by Hansman, G. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ozawa, K.
Right arrow Articles by Hansman, G. S.

 Previous Article  |  Next Article 

Journal of Clinical Microbiology, December 2007, p. 3996-4005, Vol. 45, No. 12
0095-1137/07/$08.00+0     doi:10.1128/JCM.01516-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Norovirus Infections in Symptomatic and Asymptomatic Food Handlers in Japan{triangledown}

Kazuhiro Ozawa,1 Tomoichiro Oka,2 Naokazu Takeda,2 and Grant S. Hansman2*

Chubu Food and Environmental Safety Center, Shizuoka,1 Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan2

Received 29 July 2007/ Returned for modification 11 August 2007/ Accepted 29 September 2007

Noroviruses are the leading cause of outbreaks of gastroenteritis in the world. At present, norovirus genogroup II, genotype 4 (GII/4), strains are the most prevalent in many countries. In this study we investigated 55 outbreaks and 35 sporadic cases of norovirus-associated gastroenteritis in food handlers in food-catering settings between 10 November 2005 and 9 December 2006 in Japan. Stool specimens were collected from both symptomatic and asymptomatic individuals and were examined for norovirus by real-time reverse transcription-PCR; the results were then confirmed by sequence analysis. Norovirus was detected in 449 of 2,376 (19%) specimens. Four genogroup I (GI) genotypes and 12 GII genotypes, including one new GII genotype, were detected. The GII/4 sequences were predominant, accounting for 19 of 55 (35%) outbreaks and 16 of 35 (46%) sporadic cases. Our results also showed that a large number of asymptomatic food handlers were infected with norovirus GII/4 strains. Norovirus GII had a slightly higher mean viral load (1 log unit higher) than norovirus GI, i.e., 3.81 x 108 versus 2.79 x 107 copies/g of stool. Among norovirus GI strains, GI/4 had the highest mean viral load, whereas among GII strains, GII/4 had the highest mean viral load (2.02 x 108 and 7.96 x 109 copies/g of stool, respectively). Importantly, we found that asymptomatic individuals had mean viral loads similar to those of symptomatic individuals, which may account for the increased number of infections and the predominance of an asymptomatic transmission route.

* Corresponding author. Mailing address: Department of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashi-murayama, Tokyo 208-0011, Japan. Phone: 81-42-561-0771. Fax: 81-42-561-4729. E-mail: ghansman{at}nih.go.jp

{triangledown} Published ahead of print on 10 October 2007.

Journal of Clinical Microbiology, December 2007, p. 3996-4005, Vol. 45, No. 12
0095-1137/07/$08.00+0     doi:10.1128/JCM.01516-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Glass, R. I., Parashar, U. D., Estes, M. K. (2009). Norovirus Gastroenteritis. NEJM 361: 1776-1785 [Full Text]  
  • LoBue, A. D., Thompson, J. M., Lindesmith, L., Johnston, R. E., Baric, R. S. (2009). Alphavirus-Adjuvanted Norovirus-Like Particle Vaccines: Heterologous, Humoral, and Mucosal Immune Responses Protect against Murine Norovirus Challenge. J. Virol. 83: 3212-3227 [Abstract] [Full Text]  
  • Iwai, M., Hasegawa, S., Obara, M., Nakamura, K., Horimoto, E., Takizawa, T., Kurata, T., Sogen, S.-i., Shiraki, K. (2009). Continuous Presence of Noroviruses and Sapoviruses in Raw Sewage Reflects Infections among Inhabitants of Toyama, Japan (2006 to 2008). Appl. Environ. Microbiol. 75: 1264-1270 [Abstract] [Full Text]  
  • Motomura, K., Oka, T., Yokoyama, M., Nakamura, H., Mori, H., Ode, H., Hansman, G. S., Katayama, K., Kanda, T., Tanaka, T., Takeda, N., Sato, H., and the Norovirus Surveillance Group of Japan, (2008). Identification of Monomorphic and Divergent Haplotypes in the 2006-2007 Norovirus GII/4 Epidemic Population by Genomewide Tracing of Evolutionary History. J. Virol. 82: 11247-11262 [Abstract] [Full Text]  
  • Bucardo, F., Nordgren, J., Carlsson, B., Paniagua, M., Lindgren, P.-E., Espinoza, F., Svensson, L. (2008). Pediatric Norovirus Diarrhea in Nicaragua. J. Clin. Microbiol. 46: 2573-2580 [Abstract] [Full Text]  
  • Tu, E. T.-V., Bull, R. A., Kim, M.-J., McIver, C. J., Heron, L., Rawlinson, W. D., White, P. A. (2008). Norovirus Excretion in an Aged-Care Setting. J. Clin. Microbiol. 46: 2119-2121 [Abstract] [Full Text]  
  • Okabayashi, T., Yokota, S.-i., Ohkoshi, Y., Ohuchi, H., Yoshida, Y., Kikuchi, M., Yano, K., Fujii, N. (2008). Occurrence of Norovirus Infections Unrelated to Norovirus Outbreaks in an Asymptomatic Food Handler Population. J. Clin. Microbiol. 46: 1985-1988 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»