NEW YORK (Reuters Health) - A large increase and unusual seasonal pattern of norovirus gastroenteritis in 10 European countries in 2002 appears to have been due to a new strain of the virus, according to a new report. This genotype has probably been disseminated worldwide by now, said the study’s co-author.
Dr. David Brown, a virologist at the Health Protection Agency in London, and colleagues report in the February 28th issue of The Lancet on the work of the European Food-borne Viruses Network.
The leading cause of nonbacterial gastroenteritis outbreaks, norovirus typically peaks in winter, Dr. Brown and members of the Network note. Outbreaks in the UK and the US (see Reuters Health reports, December 3, 2002 and January 16, 2003) led them to analyze epidemiological and viral characterization data from 1995 to 2002 from Germany, The Netherlands, and the UK.
“We noted a striking increase in norovirus outbreaks in 2002 that coincided with the detection and emergence of a new predominant norovirus variant of genotype II4, which had a consistent mutation in the polymerase gene,” Dr. Brown’s group writes.
They observed an atypical seasonal pattern with peak prevalence in the spring and summer. First identified in Germany and The Netherlands in January, it became the predominant cause of norovirus outbreaks throughout the continent by the end of the year.
“We saw there was at least a 100% increase in outbreaks due to this strain,” Dr. Brown told Reuters Health. “The emergence of the new strain linked to this unusual burden of disease favors the hypothesis that there was a change in antigenic structure or some biological characteristic that allowed it to spread more effectively.”
In a commentary, Dr. Carl Kirkwood points out that, of the 8 to 10 distinct clusters of norovirus, genogroup GII4 predominates worldwide. He theorizes that GII4 may have increased viability compared with other strains, but specific virulence determinants have yet to be identified.
Source: Lancet 2004;363:671-672,682-688. [ Google search on this article ]
MeSH Headings:Chronobiology: Disease Outbreaks: Environment: Environment and Public Health: Health: Health Occupations: Medicine: Periodicity: Physical Sciences: Physiological Processes: Population Characteristics: Preventive Medicine: Public Health: Seasons: Specialties, Medical: Time: Biological Sciences: Health Care: Physical SciencesCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
