Credit score: Researchers’ archive
Brazilian researchers have developed a easy take a look at 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 take a look at 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 programs and speedy point-of-care checks.
The examine was carried out on the College of São Paulo’s Biomedical Sciences Institute (ICB-USP) in partnership with researchers on the identical college’s medical college (FM-USP), and collaborators on the Federal College of West Bahia (UFOB) led by Jaime Henrique Amorim. An article reporting the findings is revealed within the Journal of Medical Virology.
Dengue is the commonest arboviral illness worldwide. It’s attributable to a flavivirus with 4 antigenically distinct serotypes (DENV-1, -2, -3 and -4) and co-circulates with at the very least 9 different flaviviruses, together with Zika (ZIKV). Similarities between DENV and ZIKV antigens result in cross-reactivity, hindering particular serological analysis.
To boost 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) referred to as EDIII, which is concerned in viral binding to human cell receptors.
Throughout the examine, carried out through the Ph.D. analysis of Samuel Santos Pereira at ICB-USP, the take a look at was initially validated with blood samples from mice experimentally contaminated with DENV and ZIKV.
This stage of the examine confirmed the take a look at’s capability to tell apart between particular antibodies towards every virus, in addition to the antibodies produced in response to all 4 DENV serotypes.
Subsequent, the take a look at was validated with round 650 blood samples donated by folks in São Paulo through 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 also tested 318 blood samples donated by healthy people with no prior diagnosis of dengue in Barreiras [a city in the western region of Bahia state, where DENV and other arboviruses are endemic], to assess the assay’s capacity to monitor specific antibodies produced in response to exposure to the viruses,” mentioned Luís Carlos de Souza Ferreira, full professor at ICB-USP and principal investigator for the examine.
In line with Ferreira, about 65% of the samples reacted to at the very 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 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,” he mentioned.
Public well being
Formally 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 niche of 17 years has alarmed specialists, who concern it could result in elevated severity in outbreaks of the illness.
In future outbreaks, Ferreira added, the take a look at 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 getting into our cells. This attribute means the take a look at can be utilized to guage 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 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,” he mentioned.
Extra info:
Samuel Santos Pereira et al, Serotype‐Particular Dengue Virus IgG Assay Utilizing EDIII‐Primarily based Recombinant Proteins and Its Software in an Endemic Inhabitants in Northeast Brazil, Journal of Medical Virology (2024). DOI: 10.1002/jmv.70100
Quotation:
Check identifies prior an infection by Zika virus and all 4 dengue virus serotypes (2025, February 27)
retrieved 27 February 2025
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