title: Emergence of Epidemic Dengue-1 Virus in the Southern Province of Sri Lanka.
abstract: BACKGROUND
  Dengue is a frequent cause of acute febrile illness with an expanding global distribution. Since the 1960s, dengue in Sri Lanka has been documented primarily along the heavily urbanized western coast with periodic shifting of serotypes. Outbreaks from 2005-2008 were attributed to a new clade of DENV-3 and more recently to a newly introduced genotype of DENV-1. In 2007, we conducted etiologic surveillance of acute febrile illness in the Southern Province and confirmed dengue in only 6.3% of febrile patients, with no cases of DENV-1 identified. To re-evaluate the importance of dengue as an etiology of acute febrile illness in this region, we renewed fever surveillance in the Southern Province to newly identify and characterize dengue.
  
  
  RESULTS
  A cross-sectional surveillance study was conducted at the largest tertiary care hospital in the Southern Province from 2012-2013. A total of 976 patients hospitalized with acute undifferentiated fever were enrolled, with 64.3% male and 31.4% children. Convalescent blood samples were collected from 877 (89.6%). Dengue virus isolation, dengue RT-PCR, and paired IgG ELISA were performed. Acute dengue was confirmed as the etiology for 388 (39.8%) of 976 hospitalizations, with most cases (291, 75.0%) confirmed virologically and by multiple methods. Among 351 cases of virologically confirmed dengue, 320 (91.2%) were due to DENV-1. Acute dengue was associated with self-reported rural residence, travel, and months having greatest rainfall. Sequencing of selected dengue viruses revealed that sequences were most closely related to those described from China and Southeast Asia, not nearby India.
  
  
  CONCLUSIONS
  We describe the first epidemic of DENV-1 in the Southern Province of Sri Lanka in a population known to be susceptible to this serotype because of prior study. Dengue accounted for 40% of acute febrile illnesses in the current study. The emergence of DENV-1 as the foremost serotype in this densely populated but agrarian population highlights the changing epidemiology of dengue and the need for continued surveillance and prevention.
authors.affiliation: Department of Medicine, Faculty of Medicine, University of Ruhuna, Galle, Sri Lanka.
authors.forename: Champica K
authors.initials: CK
authors.lastname: Bodinayake
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, United States of America.|Duke Global Health Institute, Durham, North Carolina, United States of America.
authors.forename: L Gayani
authors.initials: LG
authors.lastname: Tillekeratne
authors.affiliation: Department of Microbiology, Faculty of Medicine, University of Ruhuna, Galle, Sri Lanka.
authors.forename: Ajith
authors.initials: A
authors.lastname: Nagahawatte
authors.affiliation: Department of Pediatrics, Faculty of Medicine, University of Ruhuna, Galle, Sri Lanka.
authors.forename: Vasantha
authors.initials: V
authors.lastname: Devasiri
authors.affiliation: Teaching Hospital Karapitiya, Galle, Sri Lanka.
authors.forename: Wasantha
authors.initials: W
authors.lastname: Kodikara Arachichi
authors.affiliation: Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
authors.forename: John J
authors.initials: JJ
authors.lastname: Strouse
authors.affiliation: Emerging Infectious Diseases Programme, Duke NUS Graduate Medical School, Singapore.
authors.forename: October M
authors.initials: OM
authors.lastname: Sessions
authors.affiliation: Duke Ruhuna Collaborative Research Center, Faculty of Medicine, University of Ruhuna, Galle, Sri Lanka.
authors.forename: Ruvini
authors.initials: R
authors.lastname: Kurukulasooriya
authors.affiliation: Emerging Infectious Diseases Programme, Duke NUS Graduate Medical School, Singapore.
authors.forename: Anna
authors.initials: A
authors.lastname: Uehara
authors.affiliation: Emerging Infectious Diseases Programme, Duke NUS Graduate Medical School, Singapore.
authors.forename: Shiqin
authors.initials: S
authors.lastname: Howe
authors.affiliation: Emerging Infectious Diseases Programme, Duke NUS Graduate Medical School, Singapore.
authors.forename: Xin Mei
authors.initials: XM
authors.lastname: Ong
authors.affiliation: Emerging Infectious Diseases Programme, Duke NUS Graduate Medical School, Singapore.
authors.forename: Sharon
authors.initials: S
authors.lastname: Tan
authors.affiliation: Emerging Infectious Diseases Programme, Duke NUS Graduate Medical School, Singapore.
authors.forename: Angelia
authors.initials: A
authors.lastname: Chow
authors.affiliation: Emerging Infectious Diseases Programme, Duke NUS Graduate Medical School, Singapore.
authors.forename: Praveen
authors.initials: P
authors.lastname: Tummalapalli
authors.affiliation: Genetech Research Institute, Colombo, Sri Lanka.
authors.forename: Aruna D
authors.initials: AD
authors.lastname: De Silva
authors.affiliation: Duke Global Health Institute, Durham, North Carolina, United States of America.|Department of Community and Family Medicine, Duke University School of Medicine, Durham, North Carolina, United States of America.
authors.forename: Truls
authors.initials: T
authors.lastname: Østbye
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, United States of America.|Duke Global Health Institute, Durham, North Carolina, United States of America.|Hubert-Yeargan Center for Global Health, Durham, North Carolina, United States of America.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Woods
authors.affiliation: Emerging Infectious Diseases Programme, Duke NUS Graduate Medical School, Singapore.
authors.forename: Duane J
authors.initials: DJ
authors.lastname: Gubler
authors.affiliation: Hubert-Yeargan Center for Global Health, Durham, North Carolina, United States of America.|Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
authors.forename: Megan E
authors.initials: ME
authors.lastname: Reller
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003715:Dengue / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology*; D003716:Dengue Virus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D004196:Disease Outbreaks; D058872:Epidemics / Q000706:statistics & numerical data*; D062665:Epidemiological Monitoring; D005260:Female; D005334:Fever; D005838:Genotype; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007194:India / Q000453:epidemiology; D008297:Male; D011891:Rain; D060888:Real-Time Polymerase Chain Reaction; D012424:Rural Population; D017422:Sequence Analysis, DNA; D013188:Sri Lanka / Q000453:epidemiology; D014195:Travel; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G