Genetic diversity and molecular epidemiology of Norwalk-like viruses.
Specimens (n=287) from 59 gastroenteritis outbreaks collected from February 1997 to March 1999 were analyzed by reverse transcriptase-polymerase chain reaction. The majority of outbreaks (88%) were associated with Norwalk-like viruses. Molecular analyses of strains from 46 outbreaks showed the cocirculation during the 1998-1999 winter of 2 genogroup II clusters, accounting for 57% and 28% of outbreaks, respectively. An important genetic diversity was observed during this 2-year period. Thirteen different genogroup II strains and 3 different genogroup I strains were found. Genogroup I strains, although from the same cluster, were highly divergent (9%-16%). Epidemiologic and molecular data indicate that several introductions did not result in any major shift of prominent strains, whereas 1 apparently established itself. Some point mutations allowed corroboration of epidemiologic links and strongly suggest that, in several instances, sharing staff and/or transfer of patients between health care institutions can create a significant risk for Norwalk-like virus dissemination.
Gonin
P
P
Laboratoire de Santé Publique du Québec, 20045 Chemin Sainte-Marie, Sainte-Anne-de-Bellevue, Québec, Canada H9X 3R5. pgonin@lspq.org
Couillard
M
M
d'Halewyn
M A
MA
D001483:Base Sequence; D002139:Caliciviridae / Q000235:genetics* / Q000648:ultrastructure; D002170:Canada / Q000453:epidemiology; D004279:DNA, Viral / Q000737:chemistry; D004196:Disease Outbreaks; D005759:Gastroenteritis / Q000453:epidemiology / Q000821:virology; D014644:Genetic Variation; D006801:Humans; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction
D004279:DNA, Viral