title: A semiquantitative approach to estimate Norwalk-like virus contamination of oysters implicated in an outbreak.
abstract: Gastroenteritis outbreaks linked to shellfish consumption are numerous and Norwalk-like viruses (NLVs) are frequently the responsible causative agents. However, molecular data linking shellfish and clinical samples are still rare despite the availability of diagnostic methods. In a recent outbreak we found the same NLV sequence in stool and shellfish samples (100% identity over 313 bp in the capsid region), supporting the epidemiological data implicating the shellfish as the source of infection. A semiquantitative approach using most-probable-number-RT-PCR (MPN-RT-PCR) demonstrated the presence of a hundred of RT-PCR units per oyster. Follow-up of the oysters in the harvest area, for approximately 2 months, showed persistence of NLV contamination of the shellfish at levels up to a thousand RT-PCR units per oyster prior to depuration of the shellfish. This finding is useful in beginning to understand shellfish contamination and depuration for use in future hazard analyses.
authors.affiliation: Laboratoire de Microbiologie, IFREMER, BP 21105, 44311 Nantes cedex 03, France. sleguyad@ifremer.fr
authors.forename: Françoise S
authors.initials: FS
authors.lastname: Le Guyader
authors.forename: Frederick H
authors.initials: FH
authors.lastname: Neill
authors.forename: Eric
authors.initials: E
authors.lastname: Dubois
authors.forename: Fabienne
authors.initials: F
authors.lastname: Bon
authors.forename: Fabienne
authors.initials: F
authors.lastname: Loisy
authors.forename: Evelyne
authors.initials: E
authors.lastname: Kohli
authors.forename: Monique
authors.initials: M
authors.lastname: Pommepuy
authors.forename: Robert L
authors.initials: RL
authors.lastname: Atmar
mesh_terms: D000818:Animals; D003257:Consumer Product Safety; D004196:Disease Outbreaks; D005243:Feces / Q000821:virology; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D005759:Gastroenteritis / Q000453:epidemiology / Q000821:virology*; D006801:Humans; D029322:Norovirus / Q000302:isolation & purification*; D010125:Ostreidae / Q000821:virology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012758:Shellfish / Q000821:virology*