HMN 2025: How Test identifies prior an infection by Zika virus and all 4 dengue virus serotypes

Brazilian researchers have developed a easy check that nearly immediately tells whether or not an individual has been uncovered to any of the 4 dengue virus serotypes, in addition to Zika virus. The check is an enzyme immunoassay much like ELISA, a platform extensively utilized in laboratory testing all through Brazil. The know-how can simply be tailored to be used in automated methods and fast point-of-care assessments.

The study was performed on the University of São Paulo’s Biomedical Sciences Institute (ICB-USP) in partnership with researchers on the similar college’s medical college (FM-USP), and collaborators on the Federal University of West Bahia (UFOB) led by Jaime Henrique Amorim. An article reporting the findings is published within the Journal of Medical Virology.

Dengue is the most typical arboviral illness worldwide. It is brought on by a flavivirus with 4 antigenically distinct serotypes (DENV-1, -2, -3 and -4) and co-circulates with at the least 9 different flaviviruses, together with Zika (ZIKV). Similarities between DENV and ZIKV antigens result in cross-reactivity, hindering particular serological analysis.

To improve the assay’s accuracy in detecting antibodies within the blood of beforehand contaminated folks (even these with out obvious signs), the researchers used fragments of viral proteins, particularly part of DENV’s envelope protein (the outermost layer of the virus) generally known as EDIII, which is concerned in viral binding to human cell receptors.

During the research, performed throughout the Ph.D. analysis of Samuel Santos Pereira at ICB-USP, the check was initially validated with blood samples from mice experimentally contaminated with DENV and ZIKV.

This stage of the research confirmed the check’s capability to differentiate between particular antibodies towards every virus, in addition to the antibodies produced in response to all 4 DENV serotypes.

Next, the check was validated with round 650 blood samples donated by folks in São Paulo throughout the Brazilian Zika epidemic (2015–17). The outcomes confirmed 87.8% sensitivity (avoidance of false negatives) and 91.4% specificity (avoidance of false positives).

“We additionally examined 318 blood samples donated by wholesome folks with no prior analysis of dengue in Barreiras [a city in the western region of Bahia state, where DENV and other arboviruses are endemic], to evaluate the assay’s capability to watch particular antibodies produced in response to publicity to the viruses,” mentioned Luís Carlos de Souza Ferreira, full professor at ICB-USP and principal investigator for the research.

According to Ferreira, about 65% of the samples reacted to at the least one dengue antigen (88 to DENV-1 alone, and 90 to multiple). Curiously, solely three samples had been reactive for ZIKV, suggesting both that this virus has not circulated within the area for some years or that the particular antibodies produced in response to an infection by the virus don’t final lengthy.

“All instructed, these outcomes present that we have now a strong device for monitoring the serological immunity of anybody uncovered to those viruses, particularly individuals who dwell in areas endemic for DENV and ZIKV, or who’ve taken or plan to take one of many out there dengue vaccines,” he mentioned.

Public well being

Officially reported deaths from dengue in Brazil reached 21 within the first 4 weeks of 2025, with two-thirds occurring in São Paulo state. The reappearance of DENV-3 after a spot of 17 years has alarmed specialists, who concern it might result in elevated severity in outbreaks of the illness.

In future outbreaks, Ferreira added, the check developed at ICB-USP will serve to detect people and inhabitants teams with out immunity towards the circulating DENV serotypes, as a foundation for motion to fight the vector and apply vaccines.

“The antibodies measured within the assay [mainly immunoglobulin G, or IgG] are largely chargeable for the immunity that protects folks towards the illness, as they cease the virus from coming into our cells. This attribute means the check can be utilized to judge the immunity of wholesome individuals who have been uncovered to the viruses previously, in addition to the immunity of people that have been vaccinated.

“In the case of ZIKV, it is going to be doable to check the immunity of individuals of reproductive age and pregnant ladies, the primary at-risk teams, with out having to fret about the opportunity of cross-reactivity with antibodies produced after an infection by the 4 DENV serotypes. This will function a foundation for measures to forestall an infection when ZIKV reemerges in Brazil,” he mentioned.