title: Ecology of Merkel Cell Polyomavirus in Healthy Skin Among Individuals in an Asian Cohort.
abstract: Despite the oncogenic potential of Merkel cell polyomavirus (MCPyV), it has been found in the normal skin of healthy individuals; however, little is known about geographical variations in the ecology of MCPyV in this tissue.
  
  
  
  This study included 284 Japanese participants. Sun-unexposed arm and sun-exposed forehead skin swab samples were obtained and analyzed for MCPyV infection, using quantitative polymerase chain reaction. Phylogenetic analyses were also conducted, based on the full-length genes encoding MCPyV large T antigen and viral protein 1.
  
  
  
  This study provides the first analyses of the age-specific prevalence and levels of MCPyV infection in normal skin. Steep increases in prevalence and viral load were observed in individuals aged >40 years. MCPyV infections with a high viral load were predominantly observed in the foreheads of subjects aged >60 years, among whom a high burden of MCPyV tended to persist. Phylogenetic analyses showed that all of the gene sequences obtained in this study clustered in a major clade, suggesting the existence of an Asian/Japanese genotype.
  
  
  
  This large study suggests that MCPyV infection with high viral loads is prevalent in the sun-exposed skin of elderly adults, making it necessary to follow up this cohort for possible transformation of MCPyV to a pathogenetic form.
authors.affiliation: Department of Microbiology and Infection.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Hashida
authors.affiliation: Department of Laboratory Medicine.
authors.forename: Mikio
authors.initials: M
authors.lastname: Kamioka
authors.affiliation: Department of Microbiology and Infection.
authors.forename: Moe
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Department of Microbiology and Infection.
authors.forename: Sena
authors.initials: S
authors.lastname: Hosokawa
authors.affiliation: Department of Microbiology and Infection.
authors.forename: Masanao
authors.initials: M
authors.lastname: Murakami
authors.affiliation: Department of Dermatology.
authors.forename: Kimiko
authors.initials: K
authors.lastname: Nakajima
authors.affiliation: Department of Microbiology and Infection Department of Pediatrics, Kochi Medical School, Kochi University, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kikuchi
authors.affiliation: Department of Pediatrics, Kochi Medical School, Kochi University, Japan.
authors.forename: Mikiya
authors.initials: M
authors.lastname: Fujieda
authors.affiliation: Department of Dermatology.
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Sano
authors.affiliation: Department of Microbiology and Infection.
authors.forename: Masanori
authors.initials: M
authors.lastname: Daibata
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004279:DNA, Viral; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007564:Japan; D008297:Male; D059965:Merkel cell polyomavirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D008875:Middle Aged; D010802:Phylogeny; D027601:Polyomavirus Infections / Q000453:epidemiology / Q000821:virology*; D015995:Prevalence; D012867:Skin / Q000821:virology*; D014412:Tumor Virus Infections / Q000453:epidemiology / Q000821:virology*; D019562:Viral Load; D055815:Young Adult
chemical_list: D004279:DNA, Viral
keywords: Asian/Japanese genotype; Merkel cell polyomavirus; age-specific survey; persistent infection; phylogenetic analysis; prevalence in normal skin