The Zika virus: Lurking behind the COVID-19 pandemic?

Critical parameters on Zika virus-like particles' generation

The Zika virus became a global threat in 2015 due to its association with microcephaly. Preventing its spread depends on developing vaccines, with virus-like particles (VLP) being a promising approach, especially because of their safety profile and high immunogenicity. This study focused on the production of Zika VLP using Sf9 cells and the baculovirus expression system, evaluating cell growth kinetics, nutrient consumption, and metabolite production in Sf-900™ III medium. As a methodology, this study includes bioreactor experiments, cell density and viability quantification, nutrient and metabolite analysis, Dot Blot, Western Blot, and transmission electron microscopy. Among the critical conditions tested are culture medium supplementation with 0.028 mM cholesterol/ 6 nM bovine serum albumin, multiplicity of infection (MOI= 0.2 or 2), and dissolved oxygen tension (DOT= 5 or 30 % air saturation). As a result, in the growth phase, Sf9 cells achieved rapid exponential growth, with doubling times ranging from 22.8 to 35.4 hours and standard nutrient consumption and metabolite generation profiles for this cell line. The infection phase recorded cell death rates between 8200 and 12600 cells mL⁻¹ h⁻¹ , with higher VLP production under low MOI (0.2) and low DOT (5 %). These conditions also reduced protein degradation and nutrient consumption. The produced VLP ranged from 32 to 73 nm in size, with smaller sizes observed under low MOI conditions. Finally, controlling the DOT at 5 % air saturation without cholesterol/albumin supplementation increased VLP production without the need to raise the viral load, highlighting the importance of choosing the appropriate combination of critical parameters (MOI, DOT, and medium supplementation) as key factors in optimizing the upstream process. This finding impacts substantially upstream stage efficiency and economy, which could be useful for future scaling up to the commercial manufacturing scale.

Disruption of functional network development in children with prenatal Zika virus exposure revealed by resting-state EEG

Children born to mothers infected by Zika virus (ZIKV) during pregnancy are at increased risk of adverse neurodevelopmental outcomes including microcephaly, epilepsy, and neurocognitive deficits, collectively known as Congenital Zika Virus Syndrome. To study the impact of ZIKV on infant brain development, we collected resting-state electroencephalography (EEG) recordings from 28 normocephalic ZIKV-exposed children and 16 socio-demographically similar but unexposed children at 23-27 months of age. We assessed group differences in frequency band power and brain synchrony, as well as the relationship between these metrics and age. A significant difference (p < 0.05, Bonferroni corrected) in Inter-Site Phase Coherence was observed: median Pearson correlation coefficients were 0.15 in unexposed children and 0.07 in ZIKV-exposed children. Results showed that functional brain networks in the unexposed group were developing rapidly, in part by strengthening distal high-frequency and weakening proximal lower frequency connectivity, presumably reflecting normal synaptic growth, myelination and pruning. These maturation patterns were attenuated in the ZIKV-exposed group, suggesting that ZIKV exposure may contribute to neurodevelopmental vulnerabilities that can be detected and quantified by resting-state EEG.

Biased virus transmission following sequential coinfection of Aedes aegypti with dengue and Zika viruses

BACKGROUND

Mosquito-borne arboviruses are expanding their territory and elevating their infection prevalence due to the rapid climate change, urbanization, and increased international travel and global trade. Various significant arboviruses, including the dengue virus, Zika virus, Chikungunya virus, and yellow fever virus, are all reliant on the same primary vector, Aedes aegypti. Consequently, the occurrence of arbovirus coinfection in mosquitoes is anticipated. Arbovirus coinfection in mosquitoes has two patterns: simultaneous and sequential. Numerous studies have demonstrated that simultaneous coinfection of arboviruses in mosquitoes is unlikely to exert mutual developmental influence on these viruses. However, the viruses' interplay within a mosquito after the sequential coinfection seems intricated and not well understood.

METHODOLOGY/PRINCIPAL FINDINGS

We conducted experiments aimed at examining the phenomenon of arbovirus sequential coinfection in both mosquito cell line (C6/36) and A. aegypti, specifically focusing on dengue virus (DENV, serotype 2) and Zika virus (ZIKV). We firstly observed that DENV and ZIKV can sequentially infect mosquito C6/36 cell line, but the replication level of the subsequently infected ZIKV was significantly suppressed. Similarly, A. aegypti mosquitoes can be sequentially coinfected by these two arboviruses, regardless of the order of virus exposure. However, the replication, dissemination, and the transmission potential of the secondary virus were significantly inhibited. We preliminarily explored the underlying mechanisms, revealing that arbovirus-infected mosquitoes exhibited activated innate immunity, disrupted lipid metabolism, and enhanced RNAi pathway, leading to reduced susceptibility to the secondary arbovirus infections.

CONCLUSIONS/SIGNIFICANCE

Our findings suggest that, in contrast to simultaneous arbovirus coinfection in mosquitoes that can promote the transmission and co-circulation of these viruses, sequential coinfection appears to have limited influence on arbovirus transmission dynamics. However, it is important to note that more experimental investigations are needed to refine and expand upon this conclusion.

Advances in Zika virus vaccines and therapeutics: A systematic review

Zika virus (ZIKV) is the causative agent of a viral infection that causes neurological complications in newborns and adults worldwide. Its wide transmission route and alarming spread rates are of great concern to the scientific community. Numerous trials have been conducted to develop treatment options for ZIKV infection. This review highlights the latest developments in the fields of vaccinology and pharmaceuticals developments for ZIKV infection. A systematic and comprehensive approach was used to gather relevant and up-to-date data so that inferences could be made about the gaps in therapeutic development. The results indicate that several therapeutic interventions are being tested against ZIKV infection, such as DNA vaccines, subunit vaccines, live-attenuated vaccines, virus-vector-based vaccines, inactivated vaccines, virus-like particles, and mRNA-based vaccines. In addition, approved anti-ZIKV drugs that can reduce the global burden are discussed. Although many vaccine candidates for ZIKV are at different stages of development, none of them have received Food and Drug Authority approval for use up to now. The issue of side effects associated with these drugs in vulnerable newborns and pregnant women is a major obstacle in the therapeutic pathway.

The burden of global outbreaks: Photos of the daily lives of children with congenital Zika syndrome during the COVID-19 pandemic

INTRODUCTION

In Brazil, more than 3500 children with congenital Zika syndrome (CZS) face difficulties participating in activities of daily living, which may be aggravated by health emergencies, such as the COVID-19 pandemic. Participation could be defined as the individual's involvement in daily life situations, and participation restrictions are problems that may arise in involvement in everyday situations.

AIM

To explore the daily lives of children with CZS during the COVID-19 pandemic using photographic narratives captured by mothers and discuss possible strategies to improve participation results.

METHODS

In this participatory action research, seven young Brazilian mothers acted as co-researchers using photovoice to describe the experiences of their children with CZS (from 2 to 5 years old). Also, mothers contributed to validate the contents. The research was conducted online and included the following steps: pilot study, recruitment, individualized training, sociodemographic interview, photovoice training, photo taking, focus group for contextualization, data transcription and analysis and validation of analyses by the mothers.

RESULTS

Content analysis revealed five categories that influenced the participation of the children: participation preferences, family relationships, access to healthcare, access to education and social isolation. Regarding participation preferences, mothers reported their children's desire to play with peers and family members and have autonomy. Mothers described the family environment as a happy, peaceful and safe place for the children. Lack of therapy was perceived to negatively impact the health of children; thus, treatments were considered essential for child development. Access to education included accessibility of remote education and a perceived lack of infrastructure and pedagogical preparation. Last, social isolation due to COVID-19 directly affected the daily lives and behaviour of the children, interrupting therapies and medical appointments.

CONCLUSION

The photos and narratives captured several aspects of the daily lives of children with CZS impacted by the COVID-19 pandemic, reinforcing the importance of considering the negative effects of social isolation and offering education and social assistance to promote participation and integral health.

PATIENT/PUBLIC CONTRIBUTION

Consistent with a participatory action research framework, Mothers acted as co-researchers and participated in all stages of the research, especially in validating the data analysed by the researchers.

Developing brain under renewed attack: viral infection during pregnancy

Living in a globalized world, viral infections such as CHIKV, SARS-COV-2, and ZIKV have become inevitable to also infect the most vulnerable groups in our society. That poses a danger to these populations including pregnant women since the developing brain is sensitive to maternal stressors including viral infections. Upon maternal infection, the viruses can gain access to the fetus via the maternofetal barrier and even to the fetal brain during which factors such as viral receptor expression, time of infection, and the balance between antiviral immune responses and pro-viral mechanisms contribute to mother-to-fetus transmission and fetal infection. Both the direct pro-viral mechanisms and the resulting dysregulated immune response can cause multi-level impairment in the maternofetal and brain barriers and the developing brain itself leading to dysfunction or even loss of several cell populations. Thus, maternal viral infections can disturb brain development and even predispose to neurodevelopmental disorders. In this review, we discuss the potential contribution of maternal viral infections of three relevant relative recent players in the field: Zika, Chikungunya, and Severe Acute Respiratory Syndrome Coronavirus-2, to the impairment of brain development throughout the entire route.

Invasive hematophagous arthropods and associated diseases in a changing world

Biological invasions have increased significantly with the tremendous growth of international trade and transport. Hematophagous arthropods can be vectors of infectious and potentially lethal pathogens and parasites, thus constituting a growing threat to humans-especially when associated with biological invasions. Today, several major vector-borne diseases, currently described as emerging or re-emerging, are expanding in a world dominated by climate change, land-use change and intensive transportation of humans and goods. In this review, we retrace the historical trajectory of these invasions to better understand their ecological, physiological and genetic drivers and their impacts on ecosystems and human health. We also discuss arthropod management strategies to mitigate future risks by harnessing ecology, public health, economics and social-ethnological considerations. Trade and transport of goods and materials, including vertebrate introductions and worn tires, have historically been important introduction pathways for the most prominent invasive hematophagous arthropods, but sources and pathways are likely to diversify with future globalization. Burgeoning urbanization, climate change and the urban heat island effect are likely to interact to favor invasive hematophagous arthropods and the diseases they can vector. To mitigate future invasions of hematophagous arthropods and novel disease outbreaks, stronger preventative monitoring and transboundary surveillance measures are urgently required. Proactive approaches, such as the use of monitoring and increased engagement in citizen science, would reduce epidemiological and ecological risks and could save millions of lives and billions of dollars spent on arthropod control and disease management. Last, our capacities to manage invasive hematophagous arthropods in a sustainable way for worldwide ecosystems can be improved by promoting interactions among experts of the health sector, stakeholders in environmental issues and policymakers (e.g. the One Health approach) while considering wider social perceptions.

Challenge and opportunity for vector control strategies on key mosquito-borne diseases during the COVID-19 pandemic

Mosquito-borne diseases are major global health problems that threaten nearly half of the world's population. Conflicting resources and infrastructure required by the coronavirus disease 2019 (COVID-19) global pandemic have resulted in the vector control process being more demanding than ever. Although novel vector control paradigms may have been more applicable and efficacious in these challenging settings, there were virtually no reports of novel strategies being developed or implemented during COVID-19 pandemic. Evidence shows that the COVID-19 pandemic has dramatically impacted the implementation of conventional mosquito vector measures. Varying degrees of disruptions in malaria control and insecticide-treated nets (ITNs) and indoor residual spray (IRS) distributions worldwide from 2020 to 2021 were reported. Control measures such as mosquito net distribution and community education were significantly reduced in sub-Saharan countries. The COVID-19 pandemic has provided an opportunity for innovative vector control technologies currently being developed. Releasing sterile or lethal gene-carrying male mosquitoes and novel biopesticides may have advantages that are not matched by traditional vector measures in the current context. Here, we review the effects of COVID-19 pandemic on current vector control measures from 2020 to 2021 and discuss the future direction of vector control, taking into account probable evolving conditions of the COVID-19 pandemic.

NeuN distribution in brain structures of normal and Zika-infected suckling mice

Microcephaly is the more severe brain malformation because of Zika virus infection. Increased vulnerability of neural stem and progenitor cells to Zika infection during prenatal neurodevelopment impairs the complete formation of cortical layers. Normal development of cerebellum is also affected. However, the follow-up of apparently healthy children born to Zika exposed mothers during pregnancy has revealed other neurological sequelae. This suggests Zika infection susceptibility remains in nervous tissue after neurogenesis end, when differentiated neuronal populations predominate. The neuronal nuclear protein (NeuN) is an exclusive marker of postmitotic neurons. Changes in NeuN expression are associated with neuronal degeneration. We have evaluated immunohistochemical expression of NeuN protein in cerebral cortex, hippocampus, and cerebellum of normal and Zika-infected neonatal Balb/c mice. The highest NeuN immunoreactivity was found mainly in neurons of all cortical layers, pyramidal layer of hippocampus, granular layer of dentate gyrus and in internal granular layer of cerebellum. Viral infection caused marked loss of NeuN immunostaining in all these brain areas. This suggests neurodegenerative effects of Zika virus infection during postmitotic neuron maturation and contribute to interpretation of neuropathogenic mechanisms of Zika.

Development and validation of LC-MS/MS methods for the simultaneous quantification of sofosbuvir and its major metabolite (GS-331007) in blood plasma and cerebrospinal and seminal fluid: Application to a pilot clinical trial with a focus on Zika

Zika still poses a threat to global health owing to its association with serious neurological conditions and the absence of a vaccine and treatment. Sofosbuvir, an anti-hepatitis C drug, has shown anti-Zika effects in animal and cell models. Thus, this study aimed to develop and validate novel LC-MS/MS methods for the quantification of sofosbuvir and its major metabolite (GS-331007) in human plasma and cerebrospinal (CSF) and seminal fluid (SF), and apply the methods to a pilot clinical trial. The samples were prepared by liquid-liquid extraction and separated using isocratic mode on Gemini C₁₈ columns. Analytical detection was performed using a triple quadrupole mass spectrometer equipped with an electrospray ionization source. The validated ranges for sofosbuvir were 0.5-2,000 ng/mL (plasma) and 0.5-100 ng/mL (CSF and SF), while for the metabolite they were 2.0-2,000 ng/mL (plasma), 5.0-200 ng/mL (CSF) and 10-1,500 ng/mL (SF). The intra-day and inter-day accuracies (90.8-113.8%) and precisions (1.4-14.8%) were within the acceptance range. The developed methods fulfilled all validation parameters concerning selectivity, matrix effect, carryover, linearity, dilution integrity, precision, accuracy and stability, confirming the suitability of the method for the analysis of clinical samples.

ZIKV: Epidemiology, infection mechanism and current therapeutics

The Zika virus (ZIKV) is a vector-borne flavivirus that has been detected in 87 countries worldwide. Outbreaks of ZIKV infection have been reported from various places around the world and the disease has been declared a public health emergency of international concern. ZIKV has two modes of transmission: vector and non-vector. The ability of ZIKV to vertically transmit in its competent vectors, such as Aedes aegypti and Aedes albopictus, helps it to cope with adverse conditions, and this could be the reason for the major outbreaks that occur from time to time. ZIKV outbreaks are a global threat and, therefore, there is a need for safe and effective drugs and vaccines to fight the virus. In more than 80% of cases, ZIKV infection is asymptomatic and leads to complications, such as microcephaly in newborns and Guillain–Barré syndrome (GBS) in adults. Drugs such as sofosbuvir, chloroquine, and suramin have been found to be effective against ZIKV infections, but further evaluation of their safety in pregnant women is needed. Although temoporfin can be given to pregnant women, it needs to be tested further for side effects. Many vaccine types based on protein, vector, DNA, and mRNA have been formulated. Some vaccines, such as mRNA-1325 and VRC-ZKADNA090-00-VP, have reached Phase II clinical trials. Some new techniques should be used for formulating and testing the efficacy of vaccines. Although there have been no recent outbreaks of ZIKV infection, several studies have shown continuous circulation of ZIKV in mosquito vectors, and there is a risk of re-emergence of ZIKV in the near future. Therefore, vaccines and drugs for ZIKV should be tested further, and safe and effective therapeutic techniques should be licensed for use during outbreaks.

Meeting the Need for a Discussion of Unmet Medical Need

As Europe and the world continue to battle against COVID, the customary complacency of society over future threats is clearly on display. Just 30 months ago, such a massive disruption to global lives, livelihoods and quality of life seemed unimaginable. Some remedial European Union action is now emerging, and more is proposed, including in relation to tackling “unmet medical need” (UMN). This initiative—directing attention to the future of treating disease and contemplating incentives to stimulate research and development—is welcome in principle. But the current approach being considered by EU officials merits further discussion, because it may prove counter-productive, impeding rather than promoting innovation. This paper aims to feed into these ongoing policy discussions, and rather than presenting research in the classical sense, it discusses the key elements from a multistakeholder perspective. Its central concern is over the risk that the envisaged support will fail to generate valuable new treatments if the legislation is phrased in a rigidly linear manner that does not reflect the serpentine realities of the innovation process, or if the definition placed on unmet medical need is too restrictive. It cautions that such an approach presumes that “unmet need” can be precisely and comprehensively defined in advance on the basis of the past. It cautions that such an approach can reinforce the comfortable delusion that the future is totally predictable—the delusion that left the world as easy prey to COVID. Instead, the paper urges reflection on how the legislation that will shortly enter the pipeline can be phrased so as to allow for the flourishing of a culture capable of rapid adaptation to the unexpected.

Congenital Zika Syndrome: Genetic Avenues for Diagnosis and Therapy, Possible Management and Long-Term Outcomes

Zika virus (ZIKV) was discovered in Uganda in 1947 and was originally isolated only in Africa and Asia. After a spike of microcephaly cases in Brazil, research has closely focused on different aspects of congenital ZIKV infection. In this review, we evaluated many aspects of the disease in order to build its natural history, with a focus on the long-term clinical and neuro-radiological outcomes in children. The authors have conducted a wide-ranging search spanning the 2012–2021 period from databases PubMed, PubMed Central, Web of Science, Medline, Scopus. Different sections reflect different points of congenital ZIKV infection syndrome: pathogenesis, prenatal diagnosis, clinical signs, neuroimaging and long-term developmental outcomes. It emerged that pathogenesis has not been fully clarified and that the clinical signs are not only limited to microcephaly. Given the current absence of treatments, we proposed schemes to optimize diagnostic protocols in endemic countries. It is essential to know the key aspects of this disease to guarantee early diagnosis, even in less severe cases, and an adequate management of the main chronic problems. Considering the relatively recent discovery of this congenital infectious syndrome, further studies and updated long-term follow-up are needed to further improve management strategies for this disease.