title: Long-term viral shedding and viral genome mutation in norovirus infection.
abstract: The duration of viral shedding in the patients from two outbreaks and four sporadic cases of norovirus (NoV) infections was investigated. The longest period of viral shedding into feces was for 173 days in an inpatient from one case of outbreak. The VP1 sequence from two long-term viral shedding cases in the outbreak revealed four synonymous and one non-synonymous mutations in one inpatient at 26 days from the onset of illness, and nine synonymous and two non-synonymous mutations and a deletion, 10 synonymous mutations and a deletion in other inpatient at 29 days and 54 days from the onset of illness, respectively. Ten of the 11 amino acid positions detected in these two inpatients were in the outermost P2 domain of the viral capsid protein, and mutations at positions 295, 297, and 394 were shared in the inpatients. Mutations in the P2 domain were in epitopes A and D or near epitopes A, C, and E, suggesting that the long-term carrier state of norovirus infection contributes to the generation of escape mutants by host immunoselection.
authors.affiliation: Sakai City Institute of Public Health, Sakai, Osaka, Japan.|Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Miyoshi
authors.affiliation: Sakai City Institute of Public Health, Sakai, Osaka, Japan.
authors.forename: Kiyoko
authors.initials: K
authors.lastname: Uchino
authors.affiliation: Sakai City Institute of Public Health, Sakai, Osaka, Japan.
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Yoshida
authors.affiliation: Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.
authors.forename: Kazushi
authors.initials: K
authors.lastname: Motomura
authors.affiliation: Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.
authors.forename: Naokazu
authors.initials: N
authors.lastname: Takeda
authors.affiliation: Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Matsuura
authors.affiliation: Sakai City Institute of Public Health, Sakai, Osaka, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Tanaka
mesh_terms: D000328:Adult; D017250:Caliciviridae Infections / Q000453:epidemiology / Q000821:virology*; D002675:Child, Preschool; D004196:Disease Outbreaks; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D005243:Feces / Q000821:virology; D016679:Genome, Viral; D006801:Humans; D057131:Immune Evasion; D007223:Infant; D059645:Mutation Rate; D020125:Mutation, Missense; D029322:Norovirus / Q000235:genetics* / Q000302:isolation & purification*; D017354:Point Mutation; D013997:Time Factors; D017201:Virus Shedding
chemical_list: D000939:Epitopes
keywords: Norovirus; genome mutation; infectious gastroenteritis; long-term shedding