EID Journal Home > Volume 13, Number 8–August 2007

Volume 13, Number 8–August 2007

Human Noroviruses in Swine and Cattle
Kirsten Mattison,*  Anu Shukla,* Angela Cook,† Frank Pollari,† Robert Friendship,‡ David Kelton,‡
Sabah Bidawid,* and Jeffrey M. Farber*
*Health Canada, Ottawa, Ontario, Canada; †Public Health Agency of Canada, Guelph, Ontario,
Canada; and ‡University of Guelph, Guelph, Ontario, Canada

Human noroviruses are the predominant cause of foodborne gastroenteritis worldwide. Strains of
norovirus also exist that are uniquely associated with animals; their contribution to the incidence of
human illness remains unclear. We tested animal fecal samples and identified GIII (bovine), GII.18
(swine), and GII.4 (human) norovirus sequences, demonstrating for the first time, to our knowledge,
that GII.4-like strains can be present in livestock. In addition, we detected GII.4-like noroviral RNA
from a retail meat sample. This finding highlights a possible route for indirect zoonotic transmission of
noroviruses through the food chain.


Copyright © 2005 Elsevier SAS All rights reserved.

Genetic diversity of noroviruses in raw and treated sewage water
Again, the impact of sewage treatment bears review.

Harold van den Berga, Willemijn Loddera, Wim van der Poela, Harry Vennemab and Ana Maria de
Roda Husmana, , aMicrobiological Laboratory for Health Protection, National Institute of Public Health
and the Environment, Antonie van Leeuwenhoeklaan 9, 3720 BA Bilthoven, The Netherlands
bDiagnostic Laboratory for Infectious Diseases, National Institute of Public Health and the
Environment, Antonie van Leeuwenhoeklaan 9, 3720 BA Bilthoven, The Netherlands

Received 7 May 2004;  accepted 6 January 2005.  Available online 24 February 2005.

Human noroviruses cause gastroenteritis in humans, leading to high virus loads in sewage. Norovirus
concentrations in raw and treated sewage samples from two sewage treatment plants (STP) were
studied, along with virus removal and genetic diversity. Over one year, the average norovirus
concentrations in raw sewage were approximately 105 pcr detectable units (pdu) per liter compared
with 103 pdu/l of treated sewage. Similar sewage treatment processes at STP-A and STP-B led to
2.7 and 2.0log10-units of virus removal, respectively. In total, 11 different norovirus variants were
detected in 49 out of 53 sewage samples, with up to four different norovirus strains in a single
sewage sample. Along with GGI.6 Sindlesham and GGII.2 Melksham, the GGIIb variant was one of
the most prevalent noroviruses in both raw and treated sewage. This strain emerged among
populations in Europe in 2000 and 2001. Treated sewage containing 102–103 norovirus pdu is
discharged into the surface water. The use of such fecally contaminated surface waters for shellfish
culture, drinking water production and recreational purposes poses a potential health risk. We
showed the presence of multiple norovirus strains in raw and treated sewage, confirming the need to
clone before sequencing the RT-PCR products. Exposure to multiple norovirus strains in sewage
contaminated food or water may lead to the occurrence of norovirus recombinants, which may be
more virulent and pathogenic than the norovirus strains already circulating in the population.