Retrospective serological study on sequential dengue virus serotypes 1 to 4 epidemics in Tainan City, Taiwan, 1994 to 2000.
OBJECTIVE
We previously reported the development of a non-structural protein NS1 serotype-specific immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) for dengue serodiagnosis and seroepidemiological study. This assay can be used to differentiate the immunologic status of individuals into naive, primary, or secondary dengue virus (DENV) infection and identify the DENV serotypes of primary infection. A retrospective study was conducted to investigate the serological responses of confirmed dengue cases infected during each of the sequential DENV-1 (August 1994 to February 1995), DENV-2 (August to December 1997), DENV-3 (August 1998 to January 1999), and DENV-4 (June to December 2000) epidemics in Tainan City, Taiwan.


METHODS
218 serum samples collected 1.1 to 7.2 years postinfection were analyzed by NS1 serotype-specific IgG ELISA together with corresponding acute and/or convalescent serum samples when available. The immunological status and the infecting DENV serotypes were determined for these individuals.


RESULTS
High titers of dengue NS1 serotype-specific IgG antibody could be detected in serum samples. Differentiation of immunological status showed that 76.6% and 23.4% of cases had primary and secondary infections, respectively. A significant age-dependent increase in the rate of secondary infection was observed for those cases born before 1942. Notably, analysis of postinfection serum samples of 17 dengue hemorrhagic fever patients infected during the 1998 DENV-3 epidemic showed that 9 cases (53%) had primary infections.


CONCLUSIONS
Our data revealed that a majority of the population born after 1943 in Tainan City are naive to DENV infection and are at high risk of infection with all 4 DENV serotypes.
Chang
Shu-Fen
SF
Research and Diagnostic Center, Centers for Disease Control, Department of Health, Taipei, Taiwan.
Huang
Jyh-Hsiung
JH
Chen
Li-Kuang
LK
Su
Chien-Ling
CL
Liao
Tsai-Ling
TL
Chien
Li-Jung
LJ
Lin
Ting-Hsiang
TH
Su
Chun-Jen
CJ
Shu
Pei-Yun
PY
D000208:Acute Disease; D000367:Age Factors; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D000956:Antigens, Viral / Q000276:immunology*; D002522:Chlorocebus aethiops; D003289:Convalescence; D003715:Dengue / Q000453:epidemiology / Q000276:immunology*; D003716:Dengue Virus / Q000145:classification / Q000276:immunology*; D004196:Disease Outbreaks; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D012189:Retrospective Studies; D012703:Serotyping; D013624:Taiwan / Q000453:epidemiology; D014709:Vero Cells; D017361:Viral Nonstructural Proteins / Q000276:immunology*
D000914:Antibodies, Viral; D000956:Antigens, Viral; D007074:Immunoglobulin G; C082515:NS1 protein, dengue-1 virus; D017361:Viral Nonstructural Proteins