Interpretation of the presence of IgM and IgG antibodies in a rapid test for dengue: analysis of dengue antibody prevalence in Fortaleza City in the 20th year of the epidemic

Abstract

Introduction:The diagnosis of dengue and the differentiation between primary and secondary infections are important for monitoring the spread of the epidemic and identifying the risk of severe forms of the disease. The detection of immunoglobulin (Ig)M and IgG antibodies is the main technique for the laboratory diagnosis of dengue. The present study assessed the application of a rapid test for dengue concerning detection of new cases, reinfection recognition, and estimation of the epidemic attack rate. Methods: This was a retrospective, cross-sectional, descriptive study on dengue using the Fortaleza Health Municipal Department database. The results from 1,530 tested samples, from [2005][2006], were compared with data from epidemiological studies of dengue outbreaks in 1996, 2003, and 2010. Results: The rapid test confirmed 52% recent infections in the tested patients with clinical suspicion of dengue: 40% detected using IgM and 12% of new cases using IgG in the non-reactive IgM results. The positive IgM plus negative IgG (IgM+ plus IgG-) results showed that 38% of those patients had a recent primary dengue infection, while the positive IgG plus either positive or negative IgM (IgG+ plus IgM+/-) results indicated that 62% had dengue for at least a second time (recent secondary infections). This proportion of reinfections permitted us to estimate the attack rate as ≥62% of the population sample. Conclusions: The rapid test for dengue has enhanced our ability to detect new infections and to characterize them into primary and secondary infections, permitting the estimation of the minimal attack rate for a population during an outbreak.

Clinical manifestations of dengue in relation to dengue serotype and genotype in Malaysia: A retrospective observational study

“…One such study demonstrated a 100% sensitivity of an IgM/IgG rapid test in an attempt to distinguish between primary and secondary dengue virus infections [ 34 ]. Another study evaluated the similar rapid test kit (Dengue Duo Cassette; Panbio, Brisbane, Australia) which was also used in the present study and found that the test has good reproducibility, with the inconsistency of only 5% [ 35 ]. These findings collectively showed that the IgM/IgG rapid tests are reliable diagnostic tools for the indication of primary or secondary dengue infection.…”

Value of routine dengue diagnosis in endemic countries

“…It is suggested that IgM production occurs 4-8 d after the onset of fever and last for a couple of weeks. On the other hand, IgG production is low after primary infection but matures slowly within weeks and months and may last for several years[ 47 ]. ELISA-based IgM assays have become an important tool for the surveillance of dengue.…”

A community-based prospective cohort study of dengue viral infection in Malaysia: the study protocol

“…In each wave of data collection, the occurrence of recent primary and recent secondary infections will be examined using the approach described by Lima et al [ 38 ]. Specifically IgM + ve and IgG-ve is interpreted as a recent primary infection.…”