Persistence and Intra-Host Genetic Evolution of Zika Virus Infection in Symptomatic Adults: A Special View in the Male Reproductive System

New candidate genes potentially involved in Zika virus teratogenesis

Despite efforts to elucidate Zika virus (ZIKV) teratogenesis, still several issues remain unresolved, particularly on the molecular mechanisms behind the pathogenesis of Congenital Zika Syndrome (CZS). To answer this question, we used bioinformatics tools, animal experiments and human gene expression analysis to investigate genes related to brain development potentially involved in CZS. Searches in databases for genes related to brain development and CZS were performed, and a protein interaction network was created. The expression of these genes was analyzed in a CZS animal model and secondary gene expression analysis (DGE) was performed in human cells exposed to ZIKV. A total of 2610 genes were identified in the databases, of which 1013 were connected. By applying centrality statistics of the global network, 36 candidate genes were identified, which, after selection resulted in nine genes. Gene expression analysis revealed distinctive expression patterns for PRKDC, PCNA, ATM, SMC3 as well as for FGF8 and SHH in the CZS model. Furthermore, DGE analysis altered expression of ATM, PRKDC, PCNA. In conclusion, systems biology are helpful tools to identify candidate genes to be validated in vitro and in vivo. PRKDC, PCNA, ATM, SMC3, FGF8 and SHH have altered expression in ZIKV-induced brain malformations.

Influence of Zika virus on the cytotoxicity, cell adhesion, apoptosis and inflammatory markers of glioblastoma cells

Glioblastoma (GBM) is one of the most common types of brain tumor in adults. Despite the availability of treatments for this disease, GBM remains one of the most lethal and difficult types of tumors to treat, and thus, a majority of patients die within 2 years of diagnosis. Infection with Zika virus (ZIKV) inhibits cell proliferation and induces apoptosis, particularly in developing neuronal cells, and thus could potentially be considered an alternative for GBM treatment. In the present study, two GBM cell lines (U-138 and U-251) were infected with ZIKV at different multiplicities of infection (0.1, 0.01 and 0.001), and cell viability, migration, adhesion, induction of apoptosis, interleukin levels and CD14/CD73 cell surface marker expression were analyzed. The present study demonstrated that ZIKV infection promoted loss of cell viability and increased apoptosis in U-138 cells, as measured by MTT and triplex assay, respectively. Changes in cell migration, as determined by wound healing assay, were not observed; however, the GBM cell lines exhibited an increase in cell adhesion when compared with non-tumoral cells (Vero). The Luminex immunoassay showed a significant increase in the expression levels of IL-4 specifically in U-251 cells (MOI 0.001) following exposure to ZIKV. There was no significant change in the expression levels of IFN-γ upon ZIKV infection in the cell lines tested. Furthermore, a marked increase in the percentage of cells expressing the CD14 surface marker was observed in both GBM cell lines compared with in Vero cells; and significantly increased CD73 expression was observed particularly in U-251 cells, when compared with uninfected cells. These findings indicate that ZIKV infection could lead to reduced cell viability, elevated CD73 expression, improved cellular adherence, and higher rates of apoptosis in glioblastoma cells. Further studies are required to explore the potential use of ZIKV in the treatment of GBM.

Evidence of Zika Virus Reinfection by Genome Diversity and Antibody Response Analysis, Brazil

We generated 238 Zika virus (ZIKV) genomes from 135 persons in Brazil who had samples collected over 1 year to evaluate virus persistence. Phylogenetic inference clustered the genomes together with previously reported ZIKV strains from northern Brazil, showing that ZIKV has been remained relatively stable over time. Temporal phylogenetic analysis revealed limited within-host diversity among most ZIKV-persistent infected associated samples. However, we detected unusual virus temporal diversity from >5 persons, uncovering the existence of divergent genomes within the same patient. All those patients showed an increase in neutralizing antibody levels, followed by a decline at the convalescent phase of ZIKV infection. Of interest, in 3 of those patients, titers of neutralizing antibodies increased again after 6 months of ZIKV infection, concomitantly with real-time reverse transcription PCR re-positivity, supporting ZIKV reinfection events. Altogether, our findings provide evidence for the existence of ZIKV reinfection events.

Seroprevalence of Zika in Brazil stratified by age and geographic distribution

Congenital Zika is a devastating consequence of maternal Zika virus infections. Estimates of age-dependent seroprevalence profiles are central to our understanding of the force of Zika virus infections. We set out to calculate the age-dependent seroprevalence of Zika virus infections in Brazil. We analyzed serum samples stratified by age and geographic location, collected from 2016 to 2019, from about 16,000 volunteers enrolled in a Phase 3 dengue vaccine trial led by the Institute Butantan in Brazil. Our results show that Zika seroprevalence has a remarkable age-dependent and geographical distribution, with an average age of the first infection varying from region to region, ranging from 4.97 (3.03–5.41) to 7.24 (6.98–7.90) years. The calculated basic reproduction number, , varied from region to region, ranging from 1.18 (1.04–1.41) to 2.33 (1.54–3.85). Such data are paramount to determine the optimal age to vaccinate against Zika, if and when such a vaccine becomes available.

Zika Virus affects neurobehavioral development, and causes oxidative stress associated to blood-brain barrier disruption in a rat model of congenital infection

Zika virus (ZIKV) is a mosquito-borne flavivirus associated with several neurodevelopmental outcomes after in utero infection. Here, we studied a congenital ZIKV infection model with immunocompetent Wistar rats, able to predict disabilities and that could pave the way for proposing new effective therapies. We identified neurodevelopmental milestones disabilities in congenital ZIKV animals. Also, on 22nd postnatal day (PND), blood-brain barrier (BBB) proteins disturbances were detected in the hippocampus with immunocontent reduction of β_Catenin, Occludin and Conexin-43. Besides, oxidative stress imbalance on hippocampus and cortex were identified, without neuronal reduction in these structures. In conclusion, even without pups' microcephaly-like phenotype, congenital ZIKV infection resulted in neurobehavioral dysfunction associated with BBB and oxidative stress disturbances in young rats. Therefore, our findings highlighted the multiple impact of the congenital ZIKV infection on the neurodevelopment, which reinforces the continuity of studies to understand the spectrum of this impairment and to provide support to future treatment development for patients affected by congenital ZIKV.

Electrochemical magneto-immunoassay for detection of zika virus antibody in human serum

Zika virus (ZIKV) is a flavivirus transmitted by infected Aedes genus mosquitoes. An infected person may be asymptomatic or present symptoms such as fever, arthralgia, and in pregnancy it may lead to neurological disorders in the fetus, such as microcephaly. Based on the high dissemination potential of ZIVK and its similar antigen composition to other arboviruses, new approaches for selective virus detection are urgently needed. This work reports the development of an electrochemical immunoassay for detection of anti-ZIKV antibodies, using magnetic beads functionalized with recombinant protein derived from the non-structural protein 1 (ΔNS1-ZIKV) and anti-IgG antibodies labeled with horseradish peroxidase (HRP) enzyme. The magneto-immunoassay uses disposable microfluidic devices for detection of anti-ZIKV in serum samples. A linear response was obtained for a wide concentration range from 0.01 to 9.80 × 10⁵ pg mL^-1 (r² = 0.982), with a limit of detection of 0.48 pg mL^-1. The proposed immunoassay proved to be highly efficient for the detection of anti-ZIKV antibodies in serum, offering promising perspectives for the development of fast, simple, and affordable point-of-care diagnosis devices for ZIKV.

Unraveling the Metabolic Alterations Induced by Zika Infection in Prostate Epithelial (PNT1a) and Adenocarcinoma (PC-3) Cell Lines

The outbreak of Zika virus infection in 2016 led to the identification of its presence in several types of biofluids, including semen. Later discoveries associated Zika infection with sexual transmission and persistent replication in cells of the male reproductive tract. Prostate epithelial and carcinoma cells are favorable to virus replication, with studies pointing to transcriptomics alterations of immune and inflammation genes upon persistence. However, metabolome alterations promoted by the Zika virus in prostate cells are unknown. Given its chronic effects and oncolytic potential, we aim to investigate the metabolic alterations induced by the Zika virus in prostate epithelial (PNT1a) and adenocarcinoma (PC-3) cells using an untargeted metabolomics approach and high-resolution mass spectrometry. PNT1a cells were viable up to 15 days post ZIKV infection, in contrast to its antiproliferative effect in the PC-3 cell lineage. Remarkable alterations in the PNT1a cell metabolism were observed upon infection, especially regarding glycerolipids, fatty acids, and acylcarnitines, which could be related to viral cellular resource exploitation, in addition to the over-time increase in oxidative stress metabolites associated with carcinogenesis. The upregulation of FA20:5 at 5 dpi in PC-3 cells corroborates the antiproliferative effect observed since this metabolite was previously reported to induce PC-3 cell death. Overall, Zika virus promotes extensive lipid alterations on both PNT1a and PC-3 cells, promoting different outcomes based on the cellular metabolic state.

Evidence of Spreading Zika Virus Infection Caused by Males of Different Species

Zika virus (ZIKV) is a positive-sense single-stranded RNA flavivirus and is mainly transmitted by Aedes mosquitoes. This arbovirus has had a significant impact on health in recent years by causing malformations, such as microcephaly in babies and Guillain–Barré syndrome in adults. Some evidence indicates that ZIKV can be sexually transmitted and may persist in the male reproductive tract for an extended period in humans. Knockout and vasectomized mice have been used as models to reveal ZIKV infection in the male reproductive tract as a virus source. ZIKV presence in male and female mosquito reproductive tracts and eggs point to venereal and vertical/transovarian transmission, again demonstrating that the reproductive tract can be involved in the spread of ZIKV. Moreover, eggs protected by eggshells have the potential to be a ZIKV reservoir. Given the +-lack of vaccines and therapies for Zika fever and the underestimated prevalence rate, an understanding of ZIKV infection and its spread from the reproductive tract, which is protected from the immune system and potentially active for virus transmission, is imperative. We must also develop cheaper, more efficient techniques for virological surveillance inside vectors and humans, control vectors with ecofriendly insecticides, and promote condom use to avoid ZIKV contamination during sexual intercourse, as recommended by the World Health Organization.

Prolonged shedding of Zika virus in human semen is associated with male reproductive tract inflammation

Zika virus (ZIKV) is a mosquito-borne flavivirus that causes congenital defects. Sexual transmission of ZIKV was confirmed in a recent epidemic; however, mechanisms behind ZIKV infection and persistence in the male reproductive tract are unknown. Previously, we found that ∼33% of men with symptomatic ZIKV infections shed ZIKV RNA in semen, and some men shed ZIKV RNA for >3 months. Here, we evaluated the semen of 49 ZIKV-infected men to identify immune factors correlating with long-term ZIKV shedding in semen and ZIKV-infected cell types in semen. We found prolonged ZIKV RNA shedding in semen was associated with male reproductive tract inflammation, indicated by higher leukocyte counts and inflammatory cytokine concentrations in semen of long-term versus short-term shedders. Additionally, we found ZIKV RNA in seminal leukocytes and epithelial cells. This study of human semen from ZIKV-infected men provides critical insights into impacts of ZIKV on male reproductive tract health.

Two-step fitness selection for intra-host variations in SARS-CoV-2

Spontaneous mutations introduce uncertainty into coronavirus disease 2019 (COVID-19) control procedures and vaccine development. Here, we perform a spatiotemporal analysis on intra-host single-nucleotide variants (iSNVs) in 402 clinical samples from 170 affected individuals, which reveals an increase in genetic diversity over time after symptom onset in individuals. Nonsynonymous mutations are overrepresented in the pool of iSNVs but underrepresented at the single-nucleotide polymorphism (SNP) level, suggesting a two-step fitness selection process: a large number of nonsynonymous substitutions are generated in the host (positive selection), and these substitutions tend to be unfixed as SNPs in the population (negative selection). Dynamic iSNV changes in subpopulations with different gender, age, illness severity, and viral shedding time displayed a varied fitness selection process among populations. Our study highlights that iSNVs provide a mutational pool shaping the rapid global evolution of the virus.

Atypical Prolonged Viral Shedding With Intra-Host SARS-CoV-2 Evolution in a Mildly Affected Symptomatic Patient

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is caused by a respiratory virus with a wide range of manifestations, varying from asymptomatic to fatal cases, with a generally short outcome. However, some individuals present long-term viral shedding. We monitored 38 individuals who were mildly affected by the SARS-CoV-2 infection. Out of the total studied population, three (7.9%) showed atypical events regarding the duration of positivity for viral RNA detection. In one of these atypical cases, a previously HIV-positive male patient presented a SARS-CoV-2 RNA shedding and subgenomic RNA (sgRNA) detected from the upper respiratory tract, respectively, for 232 and 224 days after the onset of the symptoms. The SARS-CoV-2 B.1.1.28 lineage, one of the most prevalent in Brazil in 2020, was identified in this patient in three serial samples. Interestingly, the genomic analyses performed throughout the infectious process showed an increase in the genetic diversity of the B.1.1.28 lineage within the host itself, with viral clearance occurring naturally, without any intervention measures to control the infection. Contrasting widely spread current knowledge, our results indicate that potentially infectious SARS-CoV-2 virus might be shed by much longer periods by some infected patients. This data call attention to better adapted non-pharmacological measures and clinical discharge of patients aiming at preventing the spread of SARS-CoV-2 to the population.

β-Catenin Restricts Zika Virus Internalization by Downregulating Axl

The latest outbreak of Zika virus (ZIKV) in the Americas was associated with significant neurologic complications, including microcephaly of newborns. We evaluated mechanisms that regulate ZIKV entry into human fetal astrocytes (HFAs). Astrocytes are key players in maintaining brain homeostasis. We show that the central mediator of canonical Wnt signaling, β-catenin, regulates Axl, a receptor for ZIKV infection of HFAs, at the transcriptional level. In turn, ZIKV inhibited β-catenin, potentially as a mechanism to overcome its restriction of ZIKV internalization through regulation of Axl. This was evident with three ZIKV strains tested but not with a laboratory-adapted strain which has a large deletion in its envelope gene. Finally, we show that β-catenin-mediated Axl-dependent internalization of ZIKV may be of increased importance for brain cells, as it regulated ZIKV infection of astrocytes and human brain microvascular cells but not kidney epithelial (Vero) cells. Collectively, our studies reveal a role for β-catenin in ZIKV infection and highlight a dynamic interplay between ZIKV and β-catenin to modulate ZIKV entry into susceptible target cells. IMPORTANCE ZIKV is an emerging pathogen with sporadic outbreaks throughout the world. The most recent outbreak in North America was associated with small brains (microcephaly) in newborns. We studied the mechanism(s) that may regulate ZIKV entry into astrocytes. Astrocytes are a critical resident brain cell population with diverse functions that maintain brain homeostasis, including neurogenesis and neuronal survival. We show that three ZIKV strains (and not a heavily laboratory-adapted strain with a large deletion in its envelope gene) require Axl for internalization. Most importantly, we show that β-catenin, the central mediator of canonical Wnt signaling, negatively regulates Axl at the transcriptional level to prevent ZIKV internalization into human fetal astrocytes. To overcome this restriction, ZIKV downregulates β-catenin to facilitate Axl expression. This highlights a dynamic host-virus interaction whereby ZIKV inhibits β-catenin to promote its internalization into human fetal astrocytes through the induction of Axl.

Zika Virus Envelope Domain III Recombinant Protein Delivered With Saponin-Based Nanoadjuvant From Quillaja brasiliensis Enhances Anti-Zika Immune Responses, Including Neutralizing Antibodies and Splenocyte Proliferation

Nanoadjuvants that combine immunostimulatory properties and delivery systems reportedly bestow major improvements on the efficacy of recombinant, protein-based vaccines. Among these, self-assembled micellar formulations named ISCOMs (immune stimulating complexes) show a great ability to trigger powerful immunological responses against infectious pathogens. Here, a nanoadjuvant preparation, based on saponins from Quillaja brasiliensis, was evaluated together with an experimental Zika virus (ZIKV) vaccine (IQB80-zEDIII) and compared to an equivalent vaccine with alum as the standard adjuvant. The preparations were administered to mice in two doses (on days zero and 14) and immune responses were evaluated on day 28 post-priming. Serum levels of anti-Zika virus IgG, IgG1, IgG2b, IgG2c, IgG3 were significantly increased by the nanoadjuvant vaccine, compared to the mice that received the alum-adjuvanted vaccine or the unadjuvanted vaccine. In addition, a robust production of neutralizing antibodies and in vitro splenocyte proliferative responses were observed in mice immunized with IQB80-zEDIII nanoformulated vaccine. Therefore, the IQB80-zEDIII recombinant preparation seems to be a suitable candidate vaccine for ZIKV. Overall, this study identified saponin-based delivery systems as an adequate adjuvant for recombinant ZIKV vaccines and has important implications for recombinant protein-based vaccine formulations against other flaviviruses and possibly enveloped viruses.

The state of latency in microbial pathogenesis

The state of latency occurs when a microbe's persistence in a host produces host damage without perturbing homeostasis sufficiently to cause clinical symptoms or disease. The mechanisms contributing to latency are diverse and depend on the nature of both the microbe and the host. Latency has advantages for both host and microbe. The host avoids progressive damage caused by interaction with the microbe that may translate into disease, and the microbe secures a stable niche in which to survive. Latency is clinically important because some latent microbes can be transmitted to other hosts, and it is associated with a risk for recrudescent microbial growth and development of disease. In addition, it can predispose the host to other diseases, such as malignancies. Hence, latency is a temporally unstable state with an eventual outcome that mainly depends on host immunity. Latency is an integral part of the pathogenic strategies of microbes that require human (and/or mammalian) hosts, including herpesviruses, retroviruses, Mycobacterium tuberculosis, and Toxoplasma gondii. However, latency is also an outcome of infection with environmental organisms such as Cryptococcus neoformans, which require no host in their replicative cycles. For most microbes that achieve latency, there is a need for a better understanding and more investigation of host and microbial mechanisms that result in this state.

IMXQB-80: A Quillaja brasiliensis saponin-based nanoadjuvant enhances Zika virus specific immune responses in mice

Vaccine adjuvants are compounds that enhance/prolong the immune response to a co-administered antigen. Saponins have been widely used as adjuvants for many years in several vaccines - especially for intracellular pathogens - including the recent and somewhat revolutionary malaria and shingles vaccines. In view of the immunoadjuvant potential of Q. brasiliensis saponins, the present study aimed to characterize the QB-80 saponin-rich fraction and a nanoadjuvant prepared with QB-80 and lipids (IMXQB-80). In addition, the performance of such adjuvants was examined in experimental inactivated vaccines against Zika virus (ZIKV). Analysis of QB-80 by DI-ESI-ToF by negative ion electrospray revealed over 29 saponins that could be assigned to known structures existing in their congener Q. saponaria, including the well-studied QS-21 and QS-7. The QB-80 saponins were a micrOTOF able to self-assembly with lipids in ISCOM-like nanoparticles with diameters of approximately 43 nm, here named IMXQB-80. Toxicity assays revealed that QB-80 saponins did present some haemolytical and cytotoxic potentials; however, these were abrogated in IMXQB-80 nanoparticles. Regarding the adjuvant activity, QB-80 and IMXQB-80 significantly enhanced serum levels of anti-Zika virus IgG and subtypes (IgG1, IgG2b, IgG2c) as well as neutralized antibodies when compared to an unadjuvanted vaccine. Furthermore, the nanoadjuvant IMXQB-80 was as effective as QB-80 in stimulating immune responses, yet requiring fourfold less saponins to induce the equivalent stimuli, and with less toxicity. These findings reveal that the saponin fraction QB-80, and particularly the IMXQB-80 nanoadjuvant, are safe and capable of potentializing immune responses when used as adjuvants in experimental ZIKV vaccines.

Zika virus exposure affects neuron-glia communication in the hippocampal slices of adult rats

Zika virus (ZIKV) infection during pregnancy was associated with microcephaly in neonates, but clinical and experimental evidence indicate that ZIKV also causes neurological complications in adults. However, the changes in neuron-glial communication, which is essential for brain homeostasis, are still unknown. Here, we report that hippocampal slices from adult rats exposed acutely to ZIKV showed significant cellular alterations regarding to redox homeostasis, inflammatory process, neurotrophic functions and molecular signalling pathways associated with neurons and glial cells. Our findings support the hypothesis that ZIKV is highly neurotropic and its infection readily induces an inflammatory response, characterized by an increased expression and/or release of pro-inflammatory cytokines. We also observed changes in neural parameters, such as adenosine receptor A2a expression, as well as in the release of brain-derived neurotrophic factor and neuron-specific enolase, indicating plasticity synaptic impairment/neuronal damage. In addition, ZIKV induced a glial commitment, with alterations in specific and functional parameters such as aquaporin 4 expression, S100B secretion and glutathione synthesis. ZIKV also induced p21 senescence-associated gene expression, indicating that ZIKV may induce early senescence. Taken together, our results indicate that ZIKV-induced neuroinflammation, involving nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor κB (NFκB) pathways, affects important aspects of neuron-glia communication. Therefore, although ZIKV infection is transient, long-term consequences might be associated with neurological and/or neurodegenerative diseases.

Zika virus-induced brain malformations in chicken embryos

BACKGROUND

Zika virus (ZIKV) was confirmed to be related to microcephaly in 2016. However, there is still a need for understanding the embryonic morphological changes induced by ZIKV and when they occur. Here, chicken embryos were chosen as experimental model of ZIKV to evaluate virus-associated morphological alterations that might take place during embryonic development.

METHODS

A screening with different viral doses was conducted in embryos at HH Stage 10-12 (E1.5) as well as a follow up of the first 5 days postinfection (dpi) was performed to observe the main morphologic changes post ZIKV infection.

RESULTS

ZIKV exposed embryos presented a higher prevalence of mortality and defects such as brain malformation when compared to controls. Moreover, we observed that the phenotypes become more evident at 4dpi, when the viral load quantification reaches a peak.

CONCLUSIONS

We found that ZIKV exposed embryos presented a high prevalence of mortality and central nervous system (CNS) abnormalities in a dose-dependent manner. The phenotype was more evident 4 days postinfection, when the viral load quantification reached a peak.

Zika virus in rhesus macaque semen and reproductive tract tissues: a pilot study of acute infection†

Although sexual transmission of Zika virus (ZIKV) is well-documented, the viral reservoir(s) in the male reproductive tract remains uncertain in humans and immune-intact animal models. We evaluated the presence of ZIKV in a rhesus macaque pilot study to determine persistence in semen, assess the impact of infection on sperm functional characteristics, and define the viral reservoir in the male reproductive tract. Five adult male rhesus monkeys were inoculated with 105 PFU of Asian-lineage ZIKV isolate PRVABC59, and two males were inoculated with the same dose of African-lineage ZIKV DAKAR41524. Viremia and viral RNA (vRNA) shedding in semen were monitored, and a cohort of animals were necropsied for tissue collection to assess tissue vRNA burden and histopathology. All animals exhibited viremia for limited periods (1-11 days); duration of shedding did not differ significantly between viral isolates. There were sporadic low levels of vRNA in the semen from some, but not all animals. Viral RNA levels in reproductive tract tissues were also modest and present in the epididymis in three of five cases, one case in the vas deferens, but not detected in testis, seminal vesicles or prostate. ZIKV infection did not impact semen motility parameters as assessed by computer-assisted sperm analysis. Despite some evidence of prolonged ZIKV RNA shedding in human semen and high tropism of ZIKV for male reproductive tract tissues in mice deficient in Type 1 interferon signaling, in the rhesus macaques assessed in this pilot study, we did not consistently find ZIKV RNA in the male reproductive tract.

Specificity of NS1-based immunochromatographic tests for dengue virus with regard to the Zika virus protein

OBJECTIVES

This study was performed to determine whether Dengue virus (DENV) immunochromatographic tests can detect and differentiate nonstructural protein 1 (NS1) from each of the four DENV serotypes and do not cross-react with the Zika virus (ZIKV) NS1 protein.

METHODS

We compared the specificity of six NS1-based DENV immunochromatographic tests (point of care) in the detection of NS1 proteins from each of the four DENV serotypes and ZIKV. The tests were performed with NS1 proteins produced in mammalian cells. Cross-reactivity was confirmed with a purified recombinant ZIKV NS1 protein and DENV⁺ or ZIKV⁺ human serum samples.

RESULTS

Cross-reaction was observed in 2 out of the 6 evaluated tests using cell culture supernatants containing NS1 protein of each tested virus. Cross-reactivity with ZIKV was confirmed with purified recombinant ZIKV NS1 produced in Escherichia coli. Further analyses with serum samples collected from DENV⁺ or ZIKV⁺ patients confirmed the cross-reactivity with ZIKV protein in 2 tests.

CONCLUSIONS

The detection of the NS1 protein is the basis for several commercially available serological DENV diagnostic tests. The present results emphasize the relevance of testing specificity of presently available NS1-based DENV serological tests and the need of adjustments of tests that cross-react with the ZIKV protein. Our results are particularly relevant for regions where both viruses are endemically found, as in the case of Brazil.

Safety, Tumor Reduction, and Clinical Impact of Zika Virus Injection in Dogs with Advanced-Stage Brain Tumors

Malignant brain tumors are among the most aggressive cancers with poor prognosis and no effective treatment. Recently, we reported the oncolytic potential of Zika virus infecting and destroying the human central nervous system (CNS) tumors in vitro and in immunodeficient mice model. However, translating this approach to humans requires pre-clinical trials in another immunocompetent animal model. Here, we analyzed the safety of Brazilian Zika virus (ZIKV^BR) intrathecal injections in three dogs bearing spontaneous CNS tumors aiming an anti-tumoral therapy. We further assessed some aspects of the innate immune and inflammatory response that triggers the anti-tumoral response observed during the ZIKV^BR administration in vivo and in vitro. For the first time, we showed that there were no negative clinical side effects following ZIKV^BR CNS injections in dogs, confirming the safety of the procedure. Furthermore, the intrathecal ZIKV^BR injections reduced tumor size in immunocompetent dogs bearing spontaneous intracranial tumors, improved their neurological clinical symptoms significantly, and extended their survival by inducing the destruction specifically of tumor cells, sparing normal neurons, and activating an immune response. These results open new perspectives for upcoming virotherapy using ZIKV to destroy and induce an anti-tumoral immune response in CNS tumors for which there are currently no effective treatments.

A Novel Microfluidic Device Integrated with Chitosan-Modified Capillaries for Rapid ZIKV Detection

The outbreak of Zika virus (ZIKV) has posed a great challenge to public health in recent years. To address the urgent need of ZIKV RNA assays, we integrate the microfluidic chip embedded with chitosan-modified silicon dioxide capillaries, smartphone-based detection unit to be a C³-system for the rapid extraction and detection of ZIKV RNA. The C³-system is characterized by: (1) four chitosan-modified silicon dioxide capillaries integrated in the microfluidic chip for target ZIKV RNA enrichment and “in situ PCR” (polymerase chain reaction) amplification; (2) smartphone-based point of care (POC) device consisting of a pneumatic subsystem for controlling the nucleic acid extraction processes in the microfluidic chip, a heating subsystem for sample lysis and PCR amplification, and an optical subsystem for signal acquisition. The entire detection processes including sample lysis, ZIKV RNA enrichment, and reverse-transcription polymerase chain reaction (RT-PCR) is achieved in the microfluidic chip. Moreover, PCR buffers can be directly loaded into the chitosan-modified silicon dioxide capillaries for “in situ PCR”, in which the captured ZIKV RNA is directly used for downstream PCR without any loss. ZIKV RNA extracted by the C³-system can be successfully recovered at very low concentrations of 50 transducing units (TU)/mL from crude human saliva. This means that our method of detecting viremia in patients infected with ZIKV is reliable.

From Ancient to Emerging Infections: The Odyssey of Viruses in the Male Genital Tract

The male genital tract (MGT) is the target of a number of viral infections that can have deleterious consequences at the individual, offspring, and population levels. These consequences include infertility, cancers of male organs, transmission to the embryo/fetal development abnormalities, and sexual dissemination of major viral pathogens such as human immunodeficiency virus (HIV) and hepatitis B virus. Lately, two emerging viruses, Zika and Ebola, have additionally revealed that the human MGT can constitute a reservoir for viruses cleared from peripheral circulation by the immune system, leading to their sexual transmission by cured men. This represents a concern for future epidemics and further underlines the need for a better understanding of the interplay between viruses and the MGT. We review here how viruses, from ancient viruses that integrated the germline during evolution through old viruses (e.g., papillomaviruses originating from Neanderthals) and more modern sexually transmitted infections (e.g., simian zoonotic HIV) to emerging viruses (e.g., Ebola and Zika) take advantage of genital tract colonization for horizontal dissemination, viral persistence, vertical transmission, and endogenization. The MGT immune responses to viruses and the impact of these infections are discussed. We summarize the latest data regarding the sources of viruses in semen and the complex role of this body fluid in sexual transmission. Finally, we introduce key animal findings that are relevant for our understanding of viral infection and persistence in the human MGT and suggest future research directions.

Zika Virus Alters the Viscosity and Cytokines Profile in Human Colostrum

The resurgence of cases of Zika virus (ZIKV) infection, accompanied by epidemic of microcephaly in Brazil, has aroused worldwide interest in understanding the biological mechanisms of the virus that allow patient management and the viral dissemination control. Colostrum and human milk are possible sources of virus spread. Therefore, the objective of this study was to analyze the repercussions of ZIKV infection on rheological parameters and inflammatory cytokines of colostrum. The prospective cohort study included 40 puerperal donors of colostrum, divided into 2 groups: control (without ZIKV infection, n = 20) and a group infected with ZIKV during the gestational period (n = 20). Analyses were performed for the detection of ZIKV by polymerase chain reaction (PCR). In addition to obtaining the rheological parameters and quantification of IL-10 and IL-6 cytokines by flow cytometry, ZIKV and other flaviviruses were not detected in colostrum. However, maternal infection reflected increased viscosity, decreased levels of IL-10, and elevated levels of IL-6. The higher viscosity may represent a mechanical barrier that hinders the spread of the virus. The lower levels of anti-inflammatory mediators and higher inflammatory cytokines may possibly alter the viscosity, and it seems the higher viscosity represents a possible mechanism of adaptation of breastfeeding against a response to ZIKV.