title: Epidemiology and Genetic Characterization of Noroviruses among Adults in an Endemic Setting, Peruvian Amazon Basin, 2004-2011.
abstract: BACKGROUND
  Successful vaccination strategies against norovirus will require understanding the burden of disease and relevant genotypes in populations. However, few data are available from cohort studies of adults living in low- and middle-income countries (LMIC).
  
  
  METHODS
  We conducted a nested case-control study within a Peruvian military cohort to characterize the burden of norovirus infection, predominant genotypes, and associated symptoms from 2004 through 2011. Randomly selected case and control stools were tested for norovirus, bacteria, and parasites. The odds ratio of the association between norovirus infection and diarrhea was estimated using multiple logistic regression and co-infection adjusted attributable fractions were calculated.
  
  
  RESULTS
  Of the 3,818 cohort study participants, 624 developed diarrhea. Overall and norovirus-associated diarrhea incidence rates were 42.3 and 6.0 per 100 person-years, respectively. The most prevalent norovirus genogroup was GII (72.5%, 29/40), which was associated with diarrhea (AOR 3.4, 95% CI: 1.3-8.7, P = 0.012). The co-infection adjusted GII attributable fraction was 6.4%.
  
  
  CONCLUSIONS
  Norovirus was a frequent cause of diarrhea in an adult population followed longitudinally in an LMIC setting. Vaccine strategies should consider targeting adults in endemic settings and special populations that could serve as community transmission sources.
authors.affiliation: Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America; Emerging Infectious Diseases Department, United States Medical Research Unit No. 6, Lima, Peru.
authors.forename: Sarah-Blythe
authors.initials: SB
authors.lastname: Ballard
authors.affiliation: Emerging Infectious Diseases Department, United States Medical Research Unit No. 6, Lima, Peru.
authors.forename: Erik J
authors.initials: EJ
authors.lastname: Reaves
authors.affiliation: Emerging Infectious Diseases Department, United States Medical Research Unit No. 6, Lima, Peru.
authors.forename: C Giannina
authors.initials: CG
authors.lastname: Luna
authors.affiliation: Emerging Infectious Diseases Department, United States Medical Research Unit No. 6, Lima, Peru.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Silva
authors.affiliation: Bacteriology Department, United States Medical Research Unit No. 6, Lima, Peru.
authors.forename: Claudio
authors.initials: C
authors.lastname: Rocha
authors.affiliation: Bacteriology Department, United States Medical Research Unit No. 6, Lima, Peru; Department of Epidemiology, University of Washington, Seattle, Washington, United States of America.
authors.forename: Kristen
authors.initials: K
authors.lastname: Heitzinger
authors.affiliation: Department of Virology, Tohoku University Graduate School of Medicine, Sendai, Japan; Laboratorios de Investigación y Desarrollamiento, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Mayuko
authors.initials: M
authors.lastname: Saito
authors.affiliation: Laboratorios de Investigación y Desarrollamiento, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Sonia
authors.initials: S
authors.lastname: Apaza
authors.affiliation: Laboratorios de Investigación y Desarrollamiento, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Susan
authors.initials: S
authors.lastname: Espetia
authors.affiliation: Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
authors.forename: David L
authors.initials: DL
authors.lastname: Blazes
authors.affiliation: Bacteriology Department, United States Medical Research Unit No. 6, Lima, Peru.
authors.forename: Drake H
authors.initials: DH
authors.lastname: Tilley
authors.affiliation: Policlínico Militar de Chorrillos, Chorrillos, Peru.
authors.forename: Rene C
authors.initials: RC
authors.lastname: Guzmán Aguilar
authors.affiliation: Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America; Asociación Benéfica PRISMA, Lima, Peru.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Gilman
authors.affiliation: Emerging Infectious Diseases Department, United States Medical Research Unit No. 6, Lima, Peru; Department of Tropical Medicine, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana, United States of America.
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Bausch
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D001424:Bacterial Infections / Q000453:epidemiology / Q000382:microbiology; D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000821:virology; D016022:Case-Control Studies; D015331:Cohort Studies; D060085:Coinfection / Q000453:epidemiology; D015897:Comorbidity; D003967:Diarrhea / Q000453:epidemiology*; D019353:Endemic Diseases; D005243:Feces / Q000382:microbiology / Q000469:parasitology / Q000821:virology; D005838:Genotype; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008889:Military Personnel / Q000706:statistics & numerical data; D009349:Nematode Infections / Q000453:epidemiology / Q000469:parasitology; D029322:Norovirus / Q000235:genetics* / Q000502:physiology; D010568:Peru / Q000453:epidemiology; D015995:Prevalence; D011528:Protozoan Infections / Q000453:epidemiology / Q000469:parasitology; D055815:Young Adult