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Am J Trop Med Hyg. 2018 Feb;98(2):402-409. doi: 10.4269/ajtmh.17-0630. Epub 2018 Jan 4.

Epidemiological, Serological, and Virological Features of Dengue in Nha Trang City, Vietnam.

Author information

1
Institute for Vector Borne Disease, Monash University, Clayton, Australia.
2
National Institute of Hygiene and Epidemiology, Hanoi, Vietnam.
3
Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.
4
Department of Microbiology and Immunology, University of Melbourne, Doherty Institute, Melbourne, Australia.

Abstract

Vietnam is endemic for dengue. We conducted a series of retrospective and prospective studies to characterize the epidemiology of dengue and population mobility patterns in Nha Trang city, Vietnam, with a view to rational design of trials of community-level interventions. A 10-year time series of dengue case notifications showed pronounced interannual variability, as well as spatial heterogeneity in ward-level dengue incidence (median annual coefficient of variation k = 0.47). Of 451 children aged 1-10 years enrolled in a cross-sectional serosurvey, almost one-third had evidence of a past dengue virus (DENV) infection, with older children more likely to have a multitypic response indicative of past exposure to ≥ 1 serotype. All four DENV serotypes were detected in hospitalized patients during 8 months of sampling in 2015. Mobility data collected from 1,000 children and young adults via prospective travel diaries showed that, although all ages spent approximately half of their daytime hours (5:00 am-9:00 pm) at home, younger age groups (≤ 14 years) spent a significantly greater proportion of their time within 500 m of home than older respondents. Together these findings inform the rational design of future trials of dengue preventive interventions in this setting by identifying 1) children < 7 years as an optimal target group for a flavivirus-naive serological cohort, 2) children and young adults as the predominant patient population for a study with a clinical end point of symptomatic dengue, and 3) substantial spatial and temporal variations in DENV transmission, with a consequent requirement for a trial to be large enough and of long enough duration to overcome this heterogeneity.

PMID:
29313471
PMCID:
PMC5929208
DOI:
10.4269/ajtmh.17-0630
[Indexed for MEDLINE]
Free PMC Article

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