Seroepidemiology of dengue virus infection among adults in Singapore.
BACKGROUND
To determine the seroepidemiology of dengue virus infection in a representative sample of the adult resident population aged 18 years old to 74 years old in Singapore and to estimate the proportion of asymptomatic dengue infection during the 2004 epidemic.


METHODS
The study was based on 4152 stored blood samples collected between September and December 2004 from participants aged 18 years old to 74 years old during the 2004 National Health Survey. Sera were tested for IgG and IgM antibodies using a commercial test kit (PanBio Capture/Indirect ELISA).


RESULTS
Of the study population, 59.0% and 2.6% tested positive for dengue IgG (past infection) and IgM/high-titre IgG (recent infection), respectively. Only 17.2% of young adults aged 18 years old to 24 years old were dengue IgG positive. Multivariate analyses showed that older age, Indian ethnicity and male gender were significantly associated with past infection, whereas only age was significantly associated with recent dengue infection. Based on the dengue cases notified during the period of survey, it was estimated that for every 23 individuals recently infected with dengue, only 1 was reported to the health authority as a clinical case.


CONCLUSIONS
The Singapore population is highly susceptible to dengue epidemics despite its aggressive Aedes prevention and control programme. The finding of a high proportion of unreported cases due to asymptomatic and subclinical infection poses a challenge for dengue control.
Yew
Yik Weng
YW
Communicable Diseases Division, Ministry of Health, Singapore. arguzia@singnet.com.sg
Ye
Tun
T
Ang
Li Wei
LW
Ng
Lee Ching
LC
Yap
Grace
G
James
Lyn
L
Chew
Suok Kai
SK
Goh
Kee Tai
KT
D000293:Adolescent; D000328:Adult; D000330:Aedes; D000368:Aged; D000818:Animals; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D003715:Dengue / Q000453:epidemiology* / Q000635:transmission; D003716:Dengue Virus; D004196:Disease Outbreaks; D005260:Female; D006306:Health Surveys; D006801:Humans; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009032:Mosquito Control; D015999:Multivariate Analysis; D016017:Odds Ratio; D011159:Population Surveillance; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D012846:Singapore / Q000453:epidemiology; D055815:Young Adult
D007074:Immunoglobulin G; D007075:Immunoglobulin M