title: Dengue Sentinel Traveler Surveillance: Monthly and Yearly Notification Trends among Japanese Travelers, 2006-2014.
abstract: Dengue is becoming an increasing threat to non-endemic countries. In Japan, the reported number of imported cases has been rising, and the first domestic dengue outbreak in nearly 70 years was confirmed in 2014, highlighting the need for greater situational awareness and better-informed risk assessment.
  
  
  
  Using national disease surveillance data and publically available traveler statistics, we compared monthly and yearly trends in the destination country-specific dengue notification rate per 100,000 Japanese travelers with those of domestic dengue cases in the respective country visited during 2006-2014. Comparisons were made for countries accounting for the majority of importations; yearly comparisons were restricted to countries where respective national surveillance data were publicly available.
  
  
  
  There were 1007 imported Japanese dengue cases (Bali, Indonesia (n = 202), the Philippines (n = 230), Thailand (n = 160), and India (n = 152)). Consistent with historic local dengue seasonality, monthly notification rate among travelers peaked in August in Thailand, September in the Philippines, and in Bali during April with a smaller peak in August. While the number of travelers to Bali was greatest in August, the notification rate was highest in April. Annually, trends in the notification rate among travelers to the Philippines and Thailand also closely reflected local notification trends.
  
  
  
  Travelers to dengue-endemic countries appear to serve as reliable "sentinels", with the trends in estimated risk of dengue infection among Japanese travelers closely reflecting local dengue trends, both seasonally and annually. Sentinel traveler surveillance can contribute to evidence-based pretravel advice, and help inform risk assessments and decision-making for importation and potentially for subsequent secondary transmission. As our approach takes advantage of traveler data that are readily available as a proxy denominator, sentinel traveler surveillance can be a practical surveillance tool that other countries could consider for implementation.
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.|Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Munehisa
authors.initials: M
authors.lastname: Fukusumi
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.|School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Arashiro
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Arima
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Tamano
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Tomoe
authors.initials: T
authors.lastname: Shimada
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Kinoshita
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Ashley
authors.initials: A
authors.lastname: Arashiro
authors.affiliation: Department of Virology 1st, National Institute of Infectious Diseases, Tokyo, Japan.|Kanagawa Prefectural Institute of Public Health, Chigasaki, Japan.
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Takasaki
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Tomimasa
authors.initials: T
authors.lastname: Sunagawa
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Oishi
mesh_terms: D003715:Dengue / Q000453:epidemiology* / Q000821:virology; D003716:Dengue Virus / Q000302:isolation & purification; D018563:Disease Notification; D004196:Disease Outbreaks / Q000517:prevention & control; D006801:Humans; D007194:India / Q000453:epidemiology; D007214:Indonesia / Q000453:epidemiology; D007564:Japan / Q000453:epidemiology; D010679:Philippines / Q000453:epidemiology; D018570:Risk Assessment; D018571:Sentinel Surveillance; D013785:Thailand / Q000453:epidemiology; D014195:Travel