Incidence of primary dengue virus infections in Southern Vietnamese children and reactivity against other flaviviruses.
OBJECTIVE
To study the incidence of asymptomatic primary dengue infections among children and reactivity against other flaviviruses.


METHODS
A total of 216 children, who had no dengue-specific IgG antibodies during a serosurvey in 2003 were re-examined 23 months later to determine if seroconversion had occurred. Dengue-specific IgG was demonstrated with enzyme-linked immunosorbent assay (ELISA) and reactivity patterns against other flaviviruses were assessed by using immunofluorescence assay (IFA).


RESULTS
Sixty-six children had seroconverted for dengue virus-specific IgG; the true annual incidence of primary dengue was thus 17.3% (95% CI: 13.8-21.4). Japanese Encephalitis virus (JEV)-specific IgG antibodies were detected by IFA among three (4.6%) samples that showed seroconversion in the dengue ELISA, because of cross-reactivity.


CONCLUSIONS
Our findings highlight the high incidence of dengue among Vietnamese children; JEV infections are rare. The true annual incidence of dengue can be estimated with a single cross-sectional seroprevalence survey.
Thai
Khoa T D
KT
Division of Infectious Diseases, Tropical Medicine & AIDS, Academic Medical Center, Amsterdam, The Netherlands. t.d.thai@amc.uva.nl
Nga
Tran Thi Thanh
TT
Van Nam
Nguyen
N
Phuong
Hoang Lan
HL
Giao
Phan Trong
PT
Hung
Le Quoc
le Q
Binh
Tran Quang
TQ
van Doornum
Gerard J J
GJ
de Vries
Peter J
PJ
D000914:Antibodies, Viral / Q000097:blood; D002648:Child; D003430:Cross-Sectional Studies; D003715:Dengue / Q000453:epidemiology* / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D018177:Flavivirus Infections / Q000276:immunology*; D006801:Humans; D015994:Incidence; D008297:Male; D014744:Vietnam / Q000453:epidemiology
D000914:Antibodies, Viral