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SÃO PAULO, BRAZIL – Brazilian researchers have developed a rapid and accurate test capable of identifying prior exposure to all four dengue virus serotypes and the Zika virus. This innovative enzyme immunoassay, similar to the widely used ELISA, offers a significant advancement in diagnostic capabilities for these prevalent arboviral diseases.
The research, conducted at the University of São Paulo’s Biomedical Sciences Institute (ICB-USP) in collaboration with other institutions, is detailed in a study published in the Journal of Medical Virology. The test utilizes fragments of viral proteins, particularly the EDIII portion of dengue’s envelope protein, to enhance accuracy and minimize cross-reactivity between dengue and Zika antibodies.
The test was initially validated using blood samples from experimentally infected mice, confirming its ability to distinguish specific antibodies for each virus and all four dengue serotypes. Subsequent validation with approximately 650 human blood samples from the 2015-17 Brazilian Zika epidemic demonstrated 87.8% sensitivity and 91.4% specificity.
Further testing of 318 blood samples from healthy individuals in Bahia, an arbovirus-endemic region, revealed that approximately 65% had antibodies indicating prior dengue exposure, while only three samples reacted to Zika, suggesting either low recent circulation of the virus or waning antibody levels.
“All told, these results show that we have a powerful tool for monitoring the serological immunity of anyone exposed to these viruses, especially people who live in areas endemic for DENV and ZIKV, or who have taken or plan to take one of the available dengue vaccines,” said Luís Carlos de Souza Ferreira, principal investigator at ICB-USP.
The test’s ability to detect immunoglobulin G (IgG) antibodies, which provide immunity, makes it valuable for assessing immunity in previously exposed and vaccinated individuals. This is particularly crucial for monitoring at-risk groups, such as pregnant women and those of reproductive age, for Zika immunity.
In light of the recent dengue outbreaks in Brazil, including the reappearance of DENV-3, this test can serve as a vital tool for public health officials. It can identify susceptible individuals and populations, enabling targeted vector control and vaccination efforts.
“In the case of ZIKV, it will be possible to test the immunity of people of reproductive age and pregnant women, the main at-risk groups, without having to worry about the possibility of cross-reactivity with antibodies produced after infection by the four DENV serotypes. This will serve as a basis for measures to prevent infection when ZIKV reemerges in Brazil,” Ferreira added.
More information: Samuel Santos Pereira et al, Serotype‐Specific Dengue Virus IgG Assay Using EDIII‐Based Recombinant Proteins and Its Application in an Endemic Population in Northeast Brazil, Journal of Medical Virology (2024). DOI: 10.1002/jmv.70100
Disclaimer: This article is based on research published in the Journal of Medical Virology. While the test shows promising results, it is important to note that further validation and implementation studies may be required before widespread use. This information should not be interpreted as medical advice. Consult with a healthcare professional for diagnosis and testing related to dengue or Zika virus.
