Zika Virus and Future Research Directions

Creating equity in health research to drive more and better evidence

Health research is rapidly changing with evidence being gathered through new agile methods. This evolution is critical but must be globally equitable so the poorest nations do not lose out. We must harness this change to better tackle the daily burden of diseases that affect the most impoverished populations and bring research capabilities to every corner of the world so that rapid and fair responses to new pathogen are possible; anywhere they appear. We must seize this opportunity to make research easier, better and more equitable. Currently too many nations are unable to generate the evidence or translate it to directly change health outcomes in their own communities. It is essential to act and harness this emerging change in how research data can be generated and shared, so that all nations sustainably gain from this development. There are positive examples to draw on from COVID-19, but we now need to act. Here we present an initiative to develop a new framework that can guide researchers in the design and execution of their studies. This highly agile system will work by adapting to risk and complexity in any given study, whilst generating quality, safe and ethical data.

Zika Virus Pathogenesis: A Battle for Immune Evasion

Zika virus (ZIKV) infection and its associated congenital and other neurological disorders, particularly microcephaly and other fetal developmental abnormalities, constitute a World Health Organization (WHO) Zika Virus Research Agenda within the WHO’s R&D Blueprint for Action to Prevent Epidemics, and continue to be a Public Health Emergency of International Concern (PHEIC) today. ZIKV pathogenicity is initiated by viral infection and propagation across multiple placental and fetal tissue barriers, and is critically strengthened by subverting host immunity. ZIKV immune evasion involves viral non-structural proteins, genomic and non-coding RNA and microRNA (miRNA) to modulate interferon (IFN) signaling and production, interfering with intracellular signal pathways and autophagy, and promoting cellular environment changes together with secretion of cellular components to escape innate and adaptive immunity and further infect privileged immune organs/tissues such as the placenta and eyes. This review includes a description of recent advances in the understanding of the mechanisms underlying ZIKV immune modulation and evasion that strongly condition viral pathogenesis, which would certainly contribute to the development of anti-ZIKV strategies, drugs, and vaccines.

A target-mediated fuel-initiated molecular machine for high-sensitive fluorescence assay of the ZIKV gene via strand displacement reaction-based signal recovery and cycling amplification

Zika virus (ZIKV) is a serious threat to human health due to its widespread human arboviral infections, and early diagnosis is one of the keys to preventing infections from spreading, but there is a lack of highly sensitive and specific detection. In this work, a target-mediated fuel-initiated molecular machine was proposed for the high-sensitive fluorescence assay of the ZIKV gene via strand displacement reaction-based signal recovery and cycling amplification. The molecular machine was prepared by modifying AuNP surfaces with specially designed lock-like DNAs (LLDs). The LLDs assembled with a hairpin DNA (H1) and a fluorescent aDNA can be opened under the trigger of the ZIKV gene and the strand displacement reactions are further initiated with the help of the DNA fuel (H2), which results in the release of the aDNAs and ZIKV genes from the AuNPs, causing the recovery of the fluorescence signal and the cyclic amplification of the gene. The target-mediated fuel-initiated molecular machines output an amplified fluorescence signal with the enhancement of 360%, and possess good sensitivity for detecting the ZIKV gene in serum with a linear calibration curve from 100 pM to 1 fM and a low limit of detection of 0.90 fM. The molecular machines can differentiate the ZIKV gene from the single base mismatched DNA obviously and show good recovery of ZIKV gene detection, which demonstrates the good specificity, reproducibility and reliability of the highly sensitive assay for the early detection of the virus.

Immunogenicity and Efficacy of a Recombinant Human Adenovirus Type 5 Vaccine against Zika Virus

Zika virus (ZIKV) is a significant public health concern due to the pathogen's ability to be transmitted by either mosquito bite or sexual transmission, allowing spread to occur throughout the world. The potential consequences of ZIKV infection to human health, specifically neonates, necessitates the development of a safe and effective Zika virus vaccine. Here, we developed an intranasal Zika vaccine based upon the replication-deficient human adenovirus serotype 5 (hAd5) expressing ZIKV pre-membrane and envelope protein (hAd5-ZKV). The hAd5-ZKV vaccine is able to induce both cell-mediated and humoral immune responses to ZIKV epitopes. Importantly, this vaccine generated CD8⁺ T cells specific for a dominant ZIKV T cell epitope and is shown to be protective against a ZIKV challenge by using a pre-clinical model of ZIKV disease. We also demonstrate that the vaccine expresses pre-membrane and envelope protein in a confirmation recognized by ZIKV experienced individuals. Our studies demonstrate that this adenovirus-based vaccine expressing ZIKV proteins is immunogenic and protective in mice, and it encodes ZIKV proteins in a conformation recognized by the human antibody repertoire.

Development and assessment of the feasibility of a Zika family support programme: a study protocol

The Zika virus outbreak in Brazil in 2015 affected thousands of people. Zika is now known to cause congenital malformations leading to impairments and developmental delays in affected children, including Congenital Zika Syndrome (CZS). Children with CZS have complex care needs. Caregivers require significant levels of support to meet these needs, and there are large gaps in healthcare services. This study aims to develop, pilot and assess the feasibility and scalability of a community-based Family Support Programme for caregivers of children with CZS. The programme is adapted from the Getting to Know Cerebral Palsy (GTKCP) programme for the context of CZS in Brazil. GTKCP is a 10-session programme held with 6-10 caregivers in the local community. It includes practical, educational, peer-support and psychosocial aspects, which aim to improve confidence and capacity to care for a child with CP, and quality of life and empowerment of caregivers. The research project contains four components: Ascertaining need for the caregiver programme: a mixed-methods approach that included two literature reviews, interviews with key stakeholders in country, and incorporation of findings from the Social and Economic Impact of Zika study.Adapting GTKCP for the context of CZS and Brazil: undertaken with guidance from technical experts.Pilot testing the intervention: deliver the 10-session programme to one group of caregivers of children with CZS in Rio de Janeiro and another in Greater Salvador.Update the manual through fast-track learning from participant and facilitator feedback. Assessing the feasibility of the intervention for scale up: deliver the updated programme to two groups each in Rio de Janeiro and Greater Salvador, and evaluate the acceptability, demand, implementation, practicality, adaptation, integration, expansion, and limited efficacy, through questionnaires, direct observation, semi-structured interviews and cost calculation. The project has ethics approval in both the UK and Brazil.

Scientific and technological contributions of Latin America and Caribbean countries to the Zika virus outbreak

Background

The recent Zika virus (ZIKAV) epidemics disclosed a major public health threat and a scientific and technological (S&T) challenge. The lessons learned from the S&T response of Latin America and the Caribbean (LAC) countries are critical to inform further research and guide scientific investments. The present study aimed to assess how new S&T knowledge produced and disseminated regionally can contribute to address global health challenges.

Methods

Scientometric and social network analysis methods were used to assess the LAC scientific contribution and potential technological development on ZIKAV up to December 2017. ZIKAV-related publications were retrieved from the Web of Science, Scopus, and PubMed databases. Regionally published articles were obtained from SciELO (Scientific Electronic Library Online) and LILACS (Literature in the Health Sciences in Latin America and the Caribbean) databases. Patent registries were retrieved using Orbit Intelligence and Derwent Innovation. Records from each database were individually downloaded, integrated, standardized and analyzed.

Results

We retrieved 5421 ZIKAV-related publications, revealing a sharp increase from 2015 onwards. LAC countries accounted for 20% of all publications and Brazil was among the top three most central countries in the global network for ZIKAV research. A total of 274 patent families backed up by experimental evidence were retrieved. Only 5% were filed by LAC assignees, all of them based in Brazil. The largest contribution of LAC research was on the clinical manifestations of the ZIKAV infection, along with vector control, which was also the main focus of patents.

Conclusions

Our analysis offered a comprehensive overview of ZIKAV’s research and development and showed that (i) LAC countries had a key role in generating and disseminating scientific knowledge on ZIKAV; (ii) LAC countries have expressively contributed to research on ZIKAV clinical manifestations; (iii) the Brazilian scientific community was potentially very effective in knowledge sharing and diffusion in the ZIKAV research network; (iv) Brazil was the single LAC country filing patents, mostly represented by independent inventors and low-tech patents. The paper advocates the need for a continued interdisciplinary approach to improve LAC countries ability to prevent, prepare for and control future outbreaks.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6842-x) contains supplementary material, which is available to authorized users.

Establishment of a comprehensive and high throughput serological algorithm for Zika virus diagnostic testing

The previous serological algorithm for Zika virus (ZIKV) comprised screening by anti-ZIKV IgM capture ELISA (MAC-ELISA) for samples collected within 3 months postexposure or onset (MPEO). Samples positive by MAC-ELISA and samples collected beyond 3 MPEO were tested by the confirmatory plaque reduction neutralization test (PRNT), which proved laborious and time-consuming during the 2015 outbreak. Thus, we evaluated several ZIKV ELISAs to establish an anti-IgM and anti-IgG combination for use as a screening tool for all samples prior to PRNT confirmation. The MAC-ELISA or InBios-M in combination with the Euroimmun-G demonstrated sensitivities of 99.1% and 97.2%, respectively, and nonflavivirus specificity of 96.0%. Their cross-reactivities were 71.4% and 50.0%, respectively, for sera positive for Dengue virus antibodies. Due to near-perfect interrater agreement with PRNT and excellent detection of samples collected beyond 3 MPEO, these combinations were recommended as a screening protocol in a new high-throughput algorithm with special considerations for ZIKV diagnostics.

Zika outbreak aftermath: status, progress, concerns and new insights

Zika, a neurotrophic virus belonging to Flaviviridae family of viruses and transmitted by vector mosquitoes of Aedes species, took the world by storm during its recent outbreak. Its spread to newer territories, unprecedented pace of transmission, lack of existing therapeutic agents and vaccines and an empty drug pipeline raised an alarm. Uncertainty about full spectrum of diseases and its long-term consequences, newly discovered modes of transmission and controversies over vector status of mosquito species like Culex quinquefasciatus led to layers of complexity and presented new hurdles and challenges in Zika virus research. This review summarizes the progress and updates of efforts, concerns, financial burden and available resources in light of newly acquired knowledge in Zika virus research.