title: Eighteen Years of Respiratory Syncytial Virus Surveillance: Changes in Seasonality and Hospitalization Rates in Southwestern Alaska Native Children.
abstract: BACKGROUND
  Alaska Native infants from the Yukon-Kuskokwim Delta (YKD) experienced respiratory syncytial virus (RSV) hospitalization rates 5 times higher and an RSV season twice as long as the general US infant population. We describe trends in hospitalization rates and seasonality during 18 years of continuous RSV surveillance in this population and explore contributions of climate and sociodemographic factors.
  
  
  METHODS
  We abstracted clinical and RSV test information from computerized medical records at YKD Regional Hospital and Alaska Native Medical Center from 1994 to 2012 to determine hospitalization rates and RSV season timing. Descriptive village and weather data were acquired through the US Census and Alaska Climate Research Center, University of Alaska, Fairbanks, respectively.
  
  
  RESULTS
  During 1994-2012, YKD infant RSV hospitalization rates declined nearly 3-fold, from 177 to 65 per 1000 infants/yr. RSV season onset shifted later, from mid October to late December, contributing to a significantly decreased season duration, from 30 to 11 weeks. In a multivariate analysis, children from villages with more crowded households and lacking plumbed water had higher rates of RSV hospitalizations (relative rate, 1.17; P = 0.0005 and relative rate, 1.45; P = 0.0003). No association of temperature or dew point was found with the timing or severity of RSV season.
  
  
  CONCLUSIONS
  Although the RSV hospitalization rate decreased 3-fold, YKD infants still experience a hospitalization rate 3-fold higher than the general US infant population. Overcrowding and lack of plumbed water were associated with RSV hospitalization. Dramatic changes occurred in RSV seasonality, not explained by changes in climate.
authors.affiliation: From the *Arctic Investigations Program, Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Centers for Disease Control and Prevention (CDC), Anchorage, Alaska; †Division of Community Health Services, Alaska Native Tribal Health Consortium, Anchorage, Alaska; ‡Department of Pediatrics, School of Medicine, University of Washington, Seattle Children's Hospital, Seattle, Washington; §Department of Pediatrics, School of Medicine, Emory University, Atlanta, Georgia; and ¶Department of Pediatrics, Yukon Kuskokwim Health Corporation, Bethel, Alaska.
authors.forename: Dana J T
authors.initials: DJ
authors.lastname: Bruden
authors.forename: Rosalyn
authors.initials: R
authors.lastname: Singleton
authors.forename: Carolyn S
authors.initials: CS
authors.lastname: Hawk
authors.forename: Lisa R
authors.initials: LR
authors.lastname: Bulkow
authors.forename: Stephen
authors.initials: S
authors.lastname: Bentley
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Anderson
authors.forename: Leslie
authors.initials: L
authors.lastname: Herrmann
authors.forename: Lori
authors.initials: L
authors.lastname: Chikoyak
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Hennessy
mesh_terms: D000413:Alaska / Q000453:epidemiology; D002675:Child, Preschool; D002980:Climate; D003710:Demography; D062665:Epidemiological Monitoring; D005260:Female; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology* / Q000473:pathology*; D012136:Respiratory Syncytial Viruses; D012621:Seasons; D012959:Socioeconomic Factors