title: Incidence and characteristics of endemic Norwalk-like virus-associated gastroenteritis.
abstract: Endemic gastroenteritis associated with the Norwalk-like viruses (NLVs) is little understood. This study tested for NLV in gastroenteritis cases in 257 households in Melbourne, Australia, for the period September 1997 to February 1999 by a reverse transcription hemi-nested polymerase chain reaction. Positive samples were studied by nucleotide sequencing and phylogenetic analysis. NLV was detected in 73 (11.4%) of 638 faecal specimens tested. Twelve (1.9%) were NLV genogroup 1 (G1) and 61 (9.6%) NLV genogroup 2 (G2). Gastroenteritis symptoms associated with NLV G2/no other pathogens were significantly more severe than where no NLV was detected. NLV G1 and NLV G2 were detected in adults and children, males and females. NLV G2 incidence showed a marked seasonal periodicity with significant peaks in the Australian late spring/early summer periods. NLV G1 seasonality was significantly different from that of NLV G2. Seven major NLV clusters were identified by phylogenetic analysis.
authors.affiliation: Victorian Infectious Diseases Reference Laboratory, North Melbourne, Victoria, Australia. john.marshall@mh.org.au
authors.forename: John A
authors.initials: JA
authors.lastname: Marshall
authors.forename: Margaret E
authors.initials: ME
authors.lastname: Hellard
authors.forename: Martha I
authors.initials: MI
authors.lastname: Sinclair
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Fairley
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Cox
authors.forename: Michael G
authors.initials: MG
authors.lastname: Catton
authors.forename: Heath
authors.initials: H
authors.lastname: Kelly
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Wright
mesh_terms: D000293:Adolescent; D000328:Adult; D001315:Australia / Q000453:epidemiology; D017250:Caliciviridae Infections / Q000453:epidemiology / Q000503:physiopathology / Q000821:virology; D002648:Child; D002675:Child, Preschool; D019353:Endemic Diseases; D005243:Feces / Q000821:virology; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology* / Q000503:physiopathology* / Q000821:virology; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D029322:Norovirus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D012621:Seasons; D017422:Sequence Analysis, DNA