Brazilian researchers have made significant progress in combating dengue and zika viruses by developing a groundbreaking enzyme immunoassay that is capable of rapidly identifying exposure to all four serotypes of dengue virus, as well as the zika virus. This novel test aims to streamline the diagnostic process and is particularly relevant in regions endemic to these viruses. By utilizing enzyme-linked immunosorbent assay methods, similar to those widely adopted in Brazilian laboratories, the researchers have created a tool designed not only for laboratory settings but also for automated systems and rapid point-of-care testing.
Conducted at the esteemed University of São Paulo’s Biomedical Sciences Institute, in collaboration with its medical school and the Federal University of West Bahia, the research brings together a team of dedicated scientists led by Jaime Henrique Amorim and Samuel Santos Pereira. The findings of this comprehensive study were recently published in the Journal of Medical Virology, reflecting the importance of this work amidst rising dengue and zika cases in Brazil and beyond.
Dengue fever remains the most prevalent arboviral disease worldwide, characterized by its four distinct serotypes—DENV-1, DENV-2, DENV-3, and DENV-4. These serotypes co-circulate with several other flaviviruses, notably zika virus. The phenotypic similarities between dengue and zika, particularly in their antigens, create challenges in serological diagnosis, with cross-reactivity often obstructing accurate determination of previous infections. This can lead to difficulties in assessing immunity, thereby complicating public health responses in affected areas.
To address this pressing issue, the researchers honed in on a specific segment of the dengue virus’s envelope protein, known as EDIII. This protein is crucial for the virus’s interaction with human cell receptors and plays a pivotal role in the immune response. By focusing on this component, the team aims to enhance the diagnostic accuracy of the assay, allowing it to effectively detect antibodies even in individuals who may not exhibit symptoms following infection, potentially broadening the understanding of community immunity levels.
In the initial phases of the study, the test was validated using blood samples from mice that were experimentally infected with both dengue and zika viruses. This early validation stage confirmed the assay’s efficacy in distinguishing between antibodies generated in response to each viral species, as well as in differentiating between the various serotypes of dengue. The promising results of this initial testing spotlighted the potential for this assay to become a staple in performance-enhancing diagnostic strategies.
Following the animal studies, the researchers turned their attention to a human cohort, validating the assay against more than 650 blood samples collected in São Paulo amidst the Brazilian zika epidemic from 2015 to 2017. The results showcased impressive numbers, with an 87.8% sensitivity rate, minimizing the occurrence of false negatives, and a 91.4% specificity rate, ensuring a substantial avoidance of false positives. These statistics not only underscore the accuracy of the test but also highlight its potential utility in large-scale epidemiological studies.
In an additional phase of testing, the research team evaluated 318 blood samples from healthy individuals in Barreiras, a city located in the western region of Bahia state where both dengue and other arboviruses are endemic. Strikingly, around 65% of these samples reacted positively to at least one of the dengue antigens, revealing a significant level of previous exposure within the population. Meanwhile, only three samples demonstrated any reactivity to zika, indicating either a prolonged absence of the virus in the region or a potential decrease in antibody longevity following infection.
These findings emphasize a pivotal advancement in monitoring immunity against arboviral diseases, particularly for populations living in dengue and zika-endemic areas. The ability to identify individuals lacking immunity can significantly inform public health interventions, particularly during outbreaks when rapid action is required to combat the virus’s spread and to implement vaccination strategies effectively.
Furthermore, Professor Luís Carlos de Souza Ferreira, who played a crucial role as the principal investigator, noted the importance of the established assay in evaluating the immunity of various demographic groups. This is particularly relevant for pregnant women and individuals of reproductive age who are at increased risk of severe disease manifestations upon exposure. The test’s specificity will enable health officials to appraise the immunity status against both dengue and zika without the risk of misleading results due to cross-reactivity.
As Brazil faces potential re-emergence of dengue serotypes and new outbreaks, the assay developed at ICB-USP could serve as a fundamental resource in identifying vulnerable populations. By pinpointing those without adequate immunity, public health strategies can better target preventive measures, combat vector populations, and deploy effective vaccination campaigns where needed most urgently.
The successful implementation of this technology could lead to a dynamic shift in how equitable healthcare is delivered in resource-limited settings, allowing for timely and accurate assessments of arboviral exposure, thereby sustaining efforts to mitigate outbreaks. The Brazilian research community’s achievement not only bolsters local public health measures but also contributes to the global understanding of viral infections and immunity dynamics.
Moreover, the timely relevance of this test is underscored by the alarming statistics regarding dengue-related morbidity in Brazil. Reports indicated that in the first four weeks of 2025 alone, 21 deaths from dengue were confirmed, predominantly in São Paulo state, prompting increased urgency for improved diagnostic tools that can support effective public health responses. As the threat from DENV-3 resurfaces after a lengthy absence, the need for vigilant monitoring and assessment of immunity is more critical than ever.
Looking ahead, the researchers’ developments could set a benchmark for similar diagnostic advancements across various infectious diseases, showcasing the potential of immunoassays in enhancing public health endeavors worldwide. The prospects of integrating such tests into routine healthcare may enable rapid diagnosis and real-time epidemiological insights, ultimately safeguarding communities at risk.
In sum, this innovative assay not only represents a major step forward in the identification of viral exposures in humans but also holds the potential to transform public health strategies in endemic regions. Researchers are likely to continue refining the application of their assay, guided by a commitment to both advancing scientific understanding and improving population health outcomes against the backdrop of rising infectious disease threats.
Subject of Research: Dengue and Zika Virus Detection
Article Title: Serotype-Specific Dengue Virus IgG Assay Using EDIII-Based Recombinant Proteins and Its Application in an Endemic Population in Northeast Brazil
News Publication Date: 20-Dec-2024
Web References: https://onlinelibrary.wiley.com/doi/10.1002/jmv.70100
References: Information not provided
Image Credits: Information not provided
Keywords: Virus testing, Dengue fever, Zika fever, Serotyping, Antibodies, Blood samples.
