Biotechnological Advances in Gene Therapy of Hematopoietic Stem Cells: Systematic Review and Meta-Analysis

Gene therapy (GT) has emerged as a promising treatment option for disorders in the hematopoietic system, particularly primary immunodeficiencies (PID). Hematopoietic stem cells (HSCs) have gained attention due to their ability to support long-term hematopoiesis. In this study, we present a summary of research evaluating the most effective method of gene editing in HSCs for translational medicine. We conducted a systematic literature search in various databases, including Cochrane, LILACs, SciELO, and PubMed (MEDLINE), covering the period from January 1989 to June 10, 2023. The aim of this study was to identify articles that assessed the efficiency of gene editing in HSCs and clinical trials focusing on PID. Our research protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO; registration number CRD42022349850). Of the 470 studies identified in our search, 77 met the inclusion criteria. Among these, 61 studies were included in strategy 1 (gene therapy using HSC [GT-HSC]) of the systematic review (SR). We performed a meta-analysis on 17 of these studies. In addition, 16 studies were categorized under strategy 2 (clinical trials for PID). While clinical trials have demonstrated the potential benefits of GT-HSC, the safety and efficacy of gene editing still pose significant challenges. Various viral and nonviral approaches for gene delivery have been explored in basic and clinical research, with viral vectors being the most commonly used method in HSC therapeutics. Although promising, recent technologies such as CRISPR/Cas are not yet ready for efficient long-term restoration of the immune system as a whole.

[Online survey on the reasons for vaccine hesitancy against COVID-19 in children and adolescents in Brazil]

The objective is to unveil the reasons for vaccine hesitancy among parents and/or guardians of children and adolescents toward the prevention of COVID-19. This is a descriptive study, with a qualitative approach that seeks to analyze the answers to the open question "Why will you not vaccinate or have not vaccinated or are in doubt about vaccinating the children and adolescents under your responsibility, for the prevention of COVID-19?". The research included adult individuals, Brazilians, living in the country, responsible for children and adolescents under 18 years of age. Data collection took place electronically in November and December 2021. The answers were organized and processed with the support of the software Iramuteq. The textual corpus of this research was composed of the response of 1,896 participants, consisting of 87% who were hesitant (1,650) and 13% (246) of parents who intend to vaccinate but who outlined some doubts and considerations about the vaccination of children and adolescents. These are reasons why parents and/or guardians have not vaccinated or are in doubt about vaccinating the children and adolescents under their responsibility for the prevention of COVID-19: fears about vaccination regarding the conception that the vaccine is in the experimental phase, fear of adverse reactions and long-term effects. The reasons for the lack of intention to vaccinate stem from the understanding of the participants that COVID-19 in children is not serious, the risks of vaccination are greater than the benefits, and the right of choice not to vaccinate.

Genetic screening in a Brazilian cohort with inborn errors of immunity

BACKGROUND

Inherited genetic defects in immune system-related genes can result in Inborn Errors of Immunity (IEI), also known as Primary Immunodeficiencies (PID). Diagnosis of IEI disorders is challenging due to overlapping clinical manifestations. Accurate identification of disease-causing germline variants is crucial for appropriate treatment, prognosis, and genetic counseling. However, genetic sequencing is challenging in low-income countries like Brazil. This study aimed to perform genetic screening on patients treated within Brazil's public Unified Health System to identify candidate genetic variants associated with the patient's phenotype.

METHODS

Thirteen singleton unrelated patients from three hospitals in Rio de Janeiro were enrolled in this study. Genomic DNA was extracted from the peripheral blood lymphocytes of each patient, and whole exome sequencing (WES) analyses were conducted using Illumina NextSeq. Germline genetic variants in IEI-related genes were prioritized using a computational framework considering their molecular consequence in coding regions; minor allele frequency ≤ 0.01; pathogenicity classification based on American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) guidelines gathered from the VarSome clinical database; and IEI-related phenotype using the Franklin tool. The genes classification into IEI categories follows internationally recognized guidelines informed by the International Union of Immunological Societies Expert Committee. Additional methods for confirmation of the variant included Sanger sequencing, phasing analysis, and splice site prediction.

RESULTS

A total of 16 disease-causing variants in nine genes, encompassing six different IEI categories, were identified. X-Linked Agammaglobulinemia, caused by BTK variations, emerged as the most prevalent IEI disorder in the cohort. However, pathogenic and likely pathogenic variants were also reported in other known IEI-related genes, namely CD40LG, CARD11, WAS, CYBB, C6, and LRBA. Interestingly, two patients with suspected IEI exhibited pathogenic variants in non-IEI-related genes, ABCA12 and SLC25A13, potentially explaining their phenotypes.

CONCLUSIONS

Genetic screening through WES enabled the detection of potentially harmful variants associated with IEI disorders. These findings contribute to a better understanding of patients' clinical manifestations by elucidating the genetic basis underlying their phenotypes.

Rare genetic variants involved in multisystem inflammatory syndrome in children: a multicenter Brazilian cohort study

Introduction

Despite the existing data on the Multisystem Inflammatory Syndrome in Children (MIS-C), the factors that determine these patients evolution remain elusive. Answers may lie, at least in part, in genetics. It is currently under investigation that MIS-C patients may have an underlying innate error of immunity (IEI), whether of monogenic, digenic, or even oligogenic origin.

Methods

To further investigate this hypothesis, 30 patients with MIS-C were submitted to whole exome sequencing.

Results

Analyses of genes associated with MIS-C, MIS-A, severe covid-19, and Kawasaki disease identified twenty-nine patients with rare potentially damaging variants (50 variants were identified in 38 different genes), including those previously described in IFNA21 and IFIH1 genes, new variants in genes previously described in MIS-C patients (KMT2D, CFB, and PRF1), and variants in genes newly associated to MIS-C such as APOL1, TNFRSF13B, and G6PD. In addition, gene ontology enrichment pointed to the involvement of thirteen major pathways, including complement system, hematopoiesis, immune system development, and type II interferon signaling, that were not yet reported in MIS-C.

Discussion

These data strongly indicate that different gene families may favor MIS- C development. Larger cohort studies with healthy controls and other omics approaches, such as proteomics and RNAseq, will be precious to better understanding the disease dynamics.

Assessing whole-exome sequencing data from undiagnosed Brazilian patients to improve the diagnostic yield of inborn errors of immunity

OBJECTIVES

Inborn error of immunity (IEI) comprises a broad group of inherited immunological disorders that usually display an overlap in many clinical manifestations challenging their diagnosis. The identification of disease-causing variants from whole-exome sequencing (WES) data comprises the gold-standard approach to ascertain IEI diagnosis. The efforts to increase the availability of clinically relevant genomic data for these disorders constitute an important improvement in the study of rare genetic disorders. This work aims to make available WES data of Brazilian patients' suspicion of IEI without a genetic diagnosis. We foresee a broad use of this dataset by the scientific community in order to provide a more accurate diagnosis of IEI disorders.

DATA DESCRIPTION

Twenty singleton unrelated patients treated at four different hospitals in the state of Rio de Janeiro, Brazil were enrolled in our study. Half of the patients were male with mean ages of 9 ± 3, while females were 12 ± 10 years old. The WES was performed in the Illumina NextSeq platform with at least 90% of sequenced bases with a minimum of 30 reads depth. Each sample had an average of 20,274 variants, comprising 116 classified as rare pathogenic or likely pathogenic according to American College of Medical Genetics and Genomics and the Association (ACMG) guidelines. The genotype-phenotype association was impaired by the lack of detailed clinical and laboratory information, besides the unavailability of molecular and functional studies which, comprise the limitations of this study. Overall, the access to clinical exome sequencing data is limited, challenging exploratory analyses and the understanding of genetic mechanisms underlying disorders. Therefore, by making these data available, we aim to increase the number of WES data from Brazilian samples despite contributing to the study of monogenic IEI-disorders.

Social Representations of Hesitant Brazilians about Vaccination against COVID-19

BACKGROUND

The control of the COVID-19 pandemic has been a great challenge. Understanding the thoughts and beliefs underlying vaccine hesitancy can help in the formulation of public policies. The present study aimed to analyze the social representations of hesitant Brazilians about vaccination against COVID-19.

METHODS

Qualitative research guided by the Theory of Social Representations, carried out through an online survey among Brazilian adults living in Brazil. The data were analyzed using the IRaMuTeQ software.

RESULTS

Of the 173,178 respondents, 10,928 were hesitant and declared reasons for vaccination hesitation. The analysis generated three classes: mistrust of the vaccine and underestimation of the severity of the pandemic; (dis)information and distrust of political involvement; and fear of adverse reactions to COVID-19 vaccines.

CONCLUSIONS

Social knowledge, presented by the representations apprehended in this study, demonstrates difficulty in discerning the reliability of information and a social imagination full of doubts and uncertainties. Understanding the internal dynamics of these groups, with their representations of the world, is important to propose policies and actions that echo and cause changes in the understanding of the role of immunization. It is essential to shed light on the sociological imagination so that gaps filled with false information can be dismantled and confronted with scientific knowledge accessible to the population.

Willingness of Brazilian caregivers in having their children and adolescents vaccinated against Covid-19

BACKGROUND

The vaccination of children and adolescents for the prevention of Covid-19 is important to:decrease in deaths and hospitalizations, prevent multisystem inflammatory syndrome, avoid long-term complications and decrease the suspension of on-site classes. Despite of these benefits, some studies have shown that some caregivers are still hesitancy.

METHODS

This is a voluntary and anonymous online survey conducted from November 17 to December 14, 2021, in Brazil, through a free-of-charge platform with a link provided on social networks. A bivariate analysis was conducted with the independent variables, with vaccine hesitancy as the outcome variable, and a multivariate logistic model was used to calculated adjusted odds ratios.

RESULTS

The sample included 15,297 respondents. Approximately 13.3 % (2,028) of the caregivers were hesitant to vaccinate their children and adolescents against Covid-19 in at least one age group. The vaccination hesitanty rate of caregivers of children aged 0-4 years, 5-11 years and adolescents were 16 %, 13 %, 15 %, respectively. The principal factors associated with vaccine hesitancy were the following: belief that they need to wait longer, belief that children that had natural infection doesn't need to vaccinate and belief that vaccine has long term adverse effects.

INTERPRETATION

The present study showed that the willingness of caregivers to have their children and adolescents vaccinated in Brazil is high compared to data from adult and pediatric international studies. This study provides a profile of the hesitant caregivers considering their perspectives and beliefs regarding vaccines that can help the elaboration of strategies to increase vaccine adherence.

Trustworthiness of information sources on vaccines for COVID-19 prevention among Brazilians

OBJECTIVE

This study aims to assess the trustworthiness of information sources, perception of clear information about the vaccine, and strategies to increase adherence to vaccination to provide managers with information that helps establish effective communication with the population about vaccination.

METHOD

This is an online survey conducted between January 22 and 29, 2021, preceded by an Informed Consent, that aims to assess vaccine hesitancy, which corresponded to the first week of vaccination initiation to prevent COVID-19 in Brazil. Data were obtained from a questionnaire made available through a free platform and stored in Google Forms and later exported to the SPSS statistical package for analysis. The sample consisted of all questionnaires from participants who self-declared as age 18 or older, Brazilian, and residing in Brazil at the time of the survey. Incomplete records with more than 50% of blank items and duplicates were excluded. All categorical variables were analyzed from their absolute and relative frequencies. Multivariate logistic regression was performed to verify the relationship between dependent variables and independent variables.

RESULTS

The results show that trust in information sources diverges between hesitant and non-hesitant. They also showed that some participants show an overall distrust that seems to have deeper foundations than issues related only to the source of information. The high rejection of television and the WHO as sources of information among hesitant suggests that integrated actions with research institutes, public figures vaccinating, and religious leaders can help to combat vaccine hesitation. Two actors become particularly important in this dynamic, both for good and bad, and their anti-vaxxer behavior must be observed: the doctor and the Ministry of Health.

CONCLUSION

This study contributes to gathering valuable information to help understand the behavior and thinking relevant to the adherence to vaccination recommendations.

Portable wide-field digital imaging for screening of neonatal visual impairment causes in Rio de Janeiro, Brazil: a budget impact analysis

OBJECTIVE

To estimate the budget impact of portable wide-field digital imaging incorporation on screening neonatal causes of childhood blindness and visual impairment in Rio de Janeiro, Brazil.

DESIGN

Budget impact analysis.

SETTING

Rio de Janeiro, Brazil.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the direct cost of indirect binocular ophthalmoscopy, red reflex test and portable wide-field digital image screening comprising all babies born in Rio de Janeiro's government maternity wards. The secondary outcome was the budget impact of implementing portable wide-field digital image screening in Rio de Janeiro, Brazil.

RESULTS

Considering 100% coverage of maternity wards, the total budget impact between 2020 and 2024 would be US$3 820 706.04, ranging from US$3 139 844.34 to US$6 099 510.35. The additional cost would be US$3 124 457.28, ranging from US$2 714 492.26 to US$4 880 608.63.

CONCLUSION

The cost of universal digital imaging screening corresponds to less than 1% of the government health budget of the city of Rio de Janeiro. The information provided in this study may help government decision-makers evaluate the feasibility of implementing this new strategy in the municipal setting. Further health economic evaluations should be performed to verify the affordability of the implementation of this screening strategy in the Brazilian scenario, taking into account scarce human resources.

Repercussions of the COVID-19 pandemic on health professionals in the state of Rio de Janeiro / Brazil

Brazil has been severely affected by the COVID-19 pandemic. The high numbers of confirmed cases and deaths have continued unabated since the first reported case, with no flattening or downward turn in the curve. In this context, healthcare workers have been exposed uninterruptedly to stress factors throughout a year of the pandemic. The study´s aim was to identify and analyze healthcare workers´ perceptions of their feelings and concerns that have surfaced in responding to the pandemic. Method: This was a cross-sectional online qualitative survey study of 554 healthcare personnel working in the state of Rio de Janeiro during the COVID-19 pandemic. Recruitment occurred from July 20 to September 30, 2020, using an online survey, preceded byfree informed consent term. Data were analyzed with the Iramuteq software. Results: Through a dendrogram, the words with the highest chi-square were highlighted and grouped into four classes: healthcare workers´ fear of falling ill to COVID-19 and infecting their family members; work/labor issues; feelings of powerlessness and need for public policies for government action; and fatigue and burnout in the pandemic. Each word class was also illustrated by a similarity tree. Conclusion: The study revealed healthcare workers´ exacerbated fear of infection and transmission of COVID-19 to their family members, besides financial losses and feelings of powerlessness and abandonment.

Low COVID-19 vaccine hesitancy in Brazil

Background

The COVID-19 pandemic has affected the entire world, and the vaccine has emerged as a source of hope for return to normal life. Still, various countries have reported high vaccine hesitancy rates. It is important to know the vaccine hesitancy profile in Brazil to help design adequate communication strategies.

Methods

A voluntary, anonymous online survey was conducted from January 22 to 29, 2021, including resident Brazilian adults to assess factors related to vaccine hesitancy. Sociodemographic and epidemiological data were analyzed. A bivariate analysis was conducted with the independent variables, with vaccine hesitancy as the outcome variable, and a multivariate logistic model was used to calculated adjusted odds ratios.

Results

The sample included 173,178 respondents, and vaccine hesitancy was found in 10.5%. The principal factors associated with vaccine hesitancy were the following: assigning importance to the vaccinés efficacy (AOR = 16.39), fear of adverse reactions (AOR = 11.23), and assigning importance to the vaccinés country of origin (AOR = 3.72). Other risk factors were the following: male gender (AOR = 1.62), having children (AOR = 1.29), 9 years of schooling or less (AOR = 1.31), living in the Central-West region (AOR = 1.19), age ≥ 40 years (AOR = 1.17), and monthly income < U$788.68 (AOR = 1.13). The two vaccines available in Brazil, Covishield and CoronaVac, showed similar confidence, 80.13% and 76.36%, respectively, despite the higher rejection of the latter vaccinés Chinese origin.

Interpretation

This online survey confirms the low vaccine hesitancy rate among Brazilians and allowed the identification of a profile that can assist the elaboration of communication strategies to increase vaccine adherence.

Funding

National Institute of Women, Children and Adolescents Health Fernandes Figueira, FIOCRUZ, Rio de Janeiro, Brazil.

The clinical spectrum and immunopathological mechanisms underlying ZIKV-induced neurological manifestations

Since the 2015 to 2016 outbreak in America, Zika virus (ZIKV) infected almost 900,000 patients. This international public health emergency was mainly associated with a significant increase in the number of newborns with congenital microcephaly and abnormal neurologic development, known as congenital Zika syndrome (CZS). Furthermore, Guillain-Barré syndrome (GBS), a neuroimmune disorder of adults, has also been associated with ZIKV infection. Currently, the number of ZIKV-infected patients has decreased, and most of the cases recently reported present as a mild and self-limiting febrile illness. However, based on its natural history of a typical example of reemerging pathogen and the lack of specific therapeutic options against ZIKV infection, new outbreaks can occur worldwide, demanding the attention of researchers and government authorities. Here, we discuss the clinical spectrum and immunopathological mechanisms underlying ZIKV-induced neurological manifestations. Several studies have confirmed the tropism of ZIKV for neural progenitor stem cells by demonstrating the presence of ZIKV in the central nervous system (CNS) during fetal development, eliciting a deleterious inflammatory response that compromises neurogenesis and brain formation. Of note, while the neuropathology of CZS can be due to a direct viral neuropathic effect, adults may develop neuroimmune manifestations such as GBS due to poorly understood mechanisms. Antiganglioside autoantibodies have been detected in multiple patients with ZIKV infection-associated GBS, suggesting a molecular mimicry. However, further additional immunopathological mechanisms remain to be uncovered, paving the way for new therapeutic strategies.

Children's Multisystem inflammatory syndrome with myopathy

This report describes a case of multisystem inflammatory syndrome in a child that evolved with a pattern of toxic shock syndrome with coronary artery ectasia and neurological involvement, documented by magnetic resonance imaging, with changes in the corpus callosum and myopathy in the pelvic girdle and paravertebral musculature.

Impaired Thymic Output Can Be Related to the Low Immune Reconstitution and T Cell Repertoire Disturbances in Relapsing Visceral Leishmaniasis Associated HIV/AIDS Patients

Background: Visceral leishmaniasis/HIV-co-infected patients (VL/HIV) accounts for around 8% of VL reported cases in Brazil. Relapses of Leishmania infection after anti-leishmanial treatment constitute a great challenge in the clinical practice because of the disease severity and drug resistance. We have shown that non-relapsing-VL/HIV (NR-) evolved with increase of CD4⁺ T-cell counts and reduction of activated CD4⁺ and CD8⁺ T cells after anti-leishmanial treatment. This immune profile was not observed in relapsing-VL/HIV patients (R-), indicating a more severe immunological compromising degree. Elevated activation status may be related to a deficient immune reconstitution and could help to explain the frequent relapses in VL/HIV co-infection. Our aim was to evaluate if this gain of T cells was related to changes in the peripheral TCRVβ repertoire and inflammatory status, as well as the possible thymus involvement in the replenishment of these newly formed T lymphocytes.

Methods: VL/HIV patients, grouped into non-relapsing (NR- = 6) and relapsing (R- = 12) were evaluated from the active phase up to 12 months post-treatment (mpt). HIV-infected patients (non-VL) and healthy subjects (HS) were included. The TCRVβ repertoire was evaluated ex vivo by flow cytometry, whereas the plasmatic cytokine levels were assessed by Luminex assay. To evaluate the thymic output, DNA was extracted from PBMCs for TCR rearrangement excision circles (TREC) quantification by qPCR.

Results: VL/HIV cases presented an altered mobilization profile (expansions or retractions) of the TCRVβ families when compared to HS independent of the follow-up phase (p < 0.05). TCRVβ repertoire on CD4⁺ T-cells was more homogeneous in the NR-VL/HIV cases, but heterogeneous on CD8⁺ T-cells, since different Vβ-families were mobilized. NR-VL/HIV had the inflammatory pattern reduced after 6 mpt. Importantly, VL/HIV patients showed number of TREC copies lower than controls during all follow-up. An increase of recent thymic emigrants was observed in NR-VL/HIV individuals at 10 mpt compared to R- patients (p < 0.01), who maintained lower TREC contents than the HIV controls.

Conclusions: VL/HIV patients that maintain the thymic function, thus generating new T-cells, seem able to replenish the T lymphocyte compartment with effector cells, then enabling parasite control.

Inhibition by Marine Algae of Chikungunya Virus Isolated From Patients in a Recent Disease Outbreak in Rio de Janeiro

Chikungunya virus (CHIKV) infection is one of the most challenging re-emergent diseases caused by a virus, and with no specific antiviral treatment it has now become a major public health concern. In this investigation, 25 blood samples were collected from patients with characteristic CHIKV symptoms and submitted to a virus isolation protocol, which detected 3 CHIKV isolates. These samples were evaluated by sequencing for the characterization of the strains and any homology to viruses circulating in Brazil during a recent outbreak. These viruses were used for the development of antiviral assays. Subsequently, the inhibitory effects of seaweed extracts on CHIKV replication were studied. The marine species of algae tested were Bryothamnion triquetrum, Caulerpa racemosa, Laurencia dendroidea, Osmundaria obtusiloba, Ulva fasciata, and Kappaphycus alvarezii, all of which are found in different countries including Brazil. The results revealed high levels of CHIKV inhibition, including extracts of O. obtusiloba with inhibition values of 1.25 μg/mL and a selectivity index of 420. Viral inhibition was dependent on the time of addition of extract of O. obtusiloba to the infected cells, with the optimal inhibition occurring up to 16 h after infection. Neuron evaluations with O. obtusiloba were performed and demonstrated low toxicity, and in infected neurons we observed high inhibitory activity in a dose-dependent manner. These results indicate that the algal extracts may be promising novel candidates for the development of therapeutic agents against CHIKV infections.

A rapid and accurate methylation-sensitive high-resolution melting analysis assay for the diagnosis of Prader Willi and Angelman patients

Background

Prader Willi (PWS) and Angelman (AS) syndromes are rare genetic disorders characterized by deletions, uniparental disomy, and imprinting defects at chromosome 15. The loss of function of specific genes caused by genetic alterations in paternal allele causes PWS while the absence in maternal allele results AS. The laboratory diagnosis of PWS and AS is complex and demands molecular biology and cytogenetics techniques to identify the genetic mechanism related to the development of the disease. The DNA methylation analysis in chromosome 15 at the SNURF‐SNRPN locus through MS‐PCR confirms the diagnosis and distinguishes between PWS and AS. Our study aimed to establish the MS‐PCR technique associated with High‐Resolution Melting (MS‐HRM) in PWS and AS diagnostic with a single pair of primers.

Methods

We collected blood samples from 43 suspected patients to a cytogenetic and methylation analysis. The extracted DNA was treated with bisulfite to perform comparative methylation analysis.

Results

MS‐HRM and MS‐PCR agreed in 100% of cases, identifying 19(44%) PWS, 3(7%) AS, and 21(49%) Normal. FISH analysis detected four cases of PWS caused by deletions in chromosome 15.

Conclusion

The MS‐HRM showed good performance with a unique pair of primers, dispensing electrophoresis gel analysis, offering a quick and reproducible diagnostic.

Inhibition by Marine Algae of Chikungunya Virus Isolated From Patients in a Recent Disease Outbreak in Rio de Janeiro

Chikungunya virus (CHIKV) infection is one of the most challenging re-emergent diseases caused by a virus, and with no specific antiviral treatment it has now become a major public health concern. In this investigation, 25 blood samples were collected from patients with characteristic CHIKV symptoms and submitted to a virus isolation protocol, which detected 3 CHIKV isolates. These samples were evaluated by sequencing for the characterization of the strains and any homology to viruses circulating in Brazil during a recent outbreak. These viruses were used for the development of antiviral assays. Subsequently, the inhibitory effects of seaweed extracts on CHIKV replication were studied. The marine species of algae tested were Bryothamnion triquetrum, Caulerpa racemosa, Laurencia dendroidea, Osmundaria obtusiloba, Ulva fasciata, and Kappaphycus alvarezii, all of which are found in different countries including Brazil. The results revealed high levels of CHIKV inhibition, including extracts of O. obtusiloba with inhibition values of 1.25 μg/mL and a selectivity index of 420. Viral inhibition was dependent on the time of addition of extract of O. obtusiloba to the infected cells, with the optimal inhibition occurring up to 16 h after infection. Neuron evaluations with O. obtusiloba were performed and demonstrated low toxicity, and in infected neurons we observed high inhibitory activity in a dose-dependent manner. These results indicate that the algal extracts may be promising novel candidates for the development of therapeutic agents against CHIKV infections.

Challenges for molecular and serological ZIKV infection confirmation

BACKGROUND

Zika Virus (ZIKV), member of Flaviviridae family and Flavivirus genus, has recently emerged as international public health emergency after its association with neonatal microcephaly cases. Clinical diagnosis hindrance involves symptom similarities produced by other arbovirus infections, therefore laboratory confirmation is of paramount importance.

DISCUSSION

The most reliable test available is based on ZIKV RNA detection from body fluid samples. However, short viremia window periods and asymptomatic infections diminish the success rate for RT-PCR positivity. Beyond molecular detection, all serology tests in areas where other Flavivirus circulates proved to be a difficult task due to the broad range of cross-reactivity, especially with dengue pre-exposed individuals.

CONCLUSION

Altogether, lack of serological diagnostic tools brings limitations to any retrospective evaluation. Those studies are central in the context of congenital infection that could occur asymptomatically and mask prevalence and risk rates.