Zika virus: what do we know about the viral structure, mechanisms of transmission, and neurological outcomes?

Congenital Zika Virus Syndrome: Microcephaly and Orofacial Anomalies

The progressive reappearance of Zika virus (ZIKV) infections since October 2013 and its circulation in >70 countries and territories (from French Polynesia to Brazil and other countries in the Americas, with sporadic spread in Europe and the East) has long been reported as a global public health emergency. ZIKV is a virus transmitted by arthropods (arboviruses), mainly by Aedes mosquitoes. ZIKV can also be transmitted to humans through mechanisms other than vector infection such as sexual intercourse, blood transfusions, and mother-to-child transmission. The latter mode of transmission can give rise to a severe clinical form called congenital Zika syndrome (CZS), which can result in spontaneous abortion or serious pathological alterations in the fetus such as microcephaly or neurological and orofacial anomalies. In this study, beside a succinct overview of the etiological, microbiological, and epidemiological aspects and modes of transmission of Zika virus infections, we have focused our attention on the pathogenetic and histopathological aspects in pregnancy and the pathogenetic and molecular mechanisms that can determine microcephaly, and consequently the clinical alterations, typical of the fetus and newborns, in a subject affected by CZS.

Neuroethical and Societal Challenges of 21st Century Epidemics

Neurologic and neuropsychiatric manifestations of COVID-19 are affecting a growing number of people worldwide. We provide a brief overview of these manifestations, contrasting them with those of other 21st century viral epidemics, as well as mitigation strategies, and societal and moral considerations related to the pandemic. We highlight unique concerns relating to COVID-19 given the scale of infection, mental health challenges faced by health care providers and the general public, and the unprecedented social consequences, including benefits and possible harms associated with continuous connectedness using modern digital communication.

A range of new ethical concerns accompanies the neurological and neuropsychiatric manifestations of COVID-19 compared with neuro-related symptoms and sequelae of past 21st century viral epidemics and pandemics.

The unique concerns of COVID-19 can be attributed to the scale of infection, mental health impacts, and access to digital communication technology.

Anxiety associated with the ethical and moral complexities of caring for patients, triaging them during a pandemic, and anticipating surges in cases may be as detrimental to the mental well-being of frontline health care workers as post-traumatic stress.

Previous recommendations for use of digital technology, especially among children, are being reconsidered in light of the demands for remote school, work, and socialization during the pandemic.

Zika virus: - a review of the main aspects of this type of arbovirosis

The objective of this study was to integrate findings related to Zika virus from the scientific literature. An integrative review of Medline was conducted, and data search was performed using the Health Sciences Descriptor Zika virus and the following filters: full texts available; studies in humans; full articles; and publications in Portuguese, French, English, and Spanish. After application of the filters, followed by reading of the titles, abstracts, and full texts, 44 studies were included in the review, for which content analysis was performed. A large part of the literature comprised review articles (84%; N=37); the majority was in English (95%, N=42). In 2016, 84% (N=37) of our sample articles was published, while in 2017, 16% (N=7) was published. The main form of viral transmission was thorough the mosquito Aedes aegypti (N=30). In addition, sexual transmission (N=09), transmission through blood transfusion (N=16), vertical transmission (N=21) and transmission from occupational activities (N=03) occurred. It was possible to diagnose the disease by testing blood (N=22), urine (N=14), saliva (N=06), semen/sperm (N=03), cerebrospinal and amniotic fluid, and other tissues (N=02). Symptomatology occurred in 1-5 people (N=10) between 3 and 7 days after a mosquito bite (N=09). Complications observed were Guillain Barré syndrome (N=27); neurological Zika syndrome (N=27); meningitis, meningoencephalitis, and myelitis (N=07); deaths and/or newborns (N=03). The review provides scientific evidence that contributes to the care, planning and implementation of public policies.

Congenital Zika Virus Infection Induces Severe Spinal Cord Injury

We report 2 fatal cases of congenital Zika virus (ZIKV) infection. Brain anomalies, including atrophy of the cerebral cortex and brainstem, and cerebellar aplasia were observed. The spinal cord showed architectural distortion, severe neuronal loss, and microcalcifications. The ZIKV proteins and flavivirus-like particles were detected in cytoplasm of spinal neurons, and spinal cord samples were positive for ZIKV RNA.

Zika Virus Trafficking and Interactions in the Human Male Reproductive Tract

Sexual transmission of Zika virus (ZIKV) is a matter of great concern. Infectious viral particles can be shed in semen for as long as six months after infection and can be transferred to male and female sexual partners during unprotected sexual intercourse. The virus can be found inside spermatozoa and could be directly transferred to the oocyte during fertilization. Sexual transmission of ZIKV can contribute to the rise in number of infected individuals in endemic areas as well as in countries where the mosquito vector does not thrive. There is also the possibility, as has been demonstrated in mouse models, that the vaginal deposition of ZIKV particles present in semen could lead to congenital syndrome. In this paper, we review the current literature to understand ZIKV trafficking from the bloodstream to the human male reproductive tract and viral interactions with host cells in interstitial spaces, tubule walls, annexed glands and semen. We hope to highlight gaps to be filled by future research and potential routes for vaccine and antiviral development.

Achados otológicos em pacientes pós-infecção pelo zika vírus: estudos de caso

RESUMO O Zika vírus em humanos é transmitido pelo mosquito Aedes aegypti e se tornou uma emergência de saúde pública, conforme declaração da Organização Mundial de Saúde. Estudos relataram a associação do vírus com alterações auditivas em pacientes, pós-infecção. Este estudo foi concebido em função da importância da audição para a comunicação, associado aos poucos relatos sobre o impacto que o Zika vírus pode causar no sistema auditivo de indivíduos adultos. O objetivo do estudo foi caracterizar os achados otológicos em dois pacientes adultos, pós-infecção pelo Zika vírus. Foram descritos os achados otológicos de pacientes de um ambulatório de otorrinolaringologia, que apresentaram queixas auditivas logo após os sintomas clínicos de infecção pelo Zika vírus. Os dois pacientes adultos relataram os seguintes sintomas: mal-estar, erupção cutânea, artralgia, plenitude auricular e perda auditiva. Exame sorológico reagente para Zika vírus (IgG). Os achados audiológicos foram: perda auditiva periférica unilateral em um paciente, alterações de reflexos contralaterais em ambos e do potencial evocado de tronco encefálico em um paciente. Os achados audiológicos demonstram possível envolvimento neuronal nas queixas apresentadas, associado, ou não, ao componente periférico, nos pacientes infectados pelo Zika vírus.

Recent Perspectives on Genome, Transmission, Clinical Manifestation, Diagnosis, Therapeutic Strategies, Vaccine Developments, and Challenges of Zika Virus Research

One of the potential threats to public health microbiology in 21st century is the increased mortality rate caused by Zika virus (ZIKV), a mosquito-borne flavivirus. The severity of ZIKV infection urged World Health Organization (WHO) to declare this virus as a global concern. The limited knowledge on the structure, virulent factors, and replication mechanism of the virus posed as hindrance for vaccine development. Several vector and non-vector-borne mode of transmission are observed for spreading the disease. The similarities of the virus with other flaviviruses such as dengue and West Nile virus are worrisome; hence, there is high scope to undertake ZIKV research that probably provide insight for novel therapeutic intervention. Thus, this review focuses on the recent aspect of ZIKV research which includes the outbreak, genome structure, multiplication and propagation of the virus, current animal models, clinical manifestations, available treatment options (probable vaccines and therapeutics), and the recent advancements in computational drug discovery pipelines, challenges and limitation to undertake ZIKV research. The review suggests that the infection due to ZIKV became one of the universal concerns and an interdisciplinary environment of in vitro cellular assays, genomics, proteomics, and computational biology approaches probably contribute insights for screening of novel molecular targets for drug design. The review tried to provide cutting edge knowledge in ZIKV research with future insights required for the development of novel therapeutic remedies to curtail ZIKV infection.

Advances in research on Zika virus

Zika virus (ZIKV) is rapidly spreading across the America and its devastating outcomes for pregnant women and infants have driven this previously ignored pathogen into the limelight. Clinical manifestations are fever, joint pain or rash and conjunctivitis. Emergence of ZIKV started with a first outbreak in the Pacific area in 2007, a second large outbreak occurred in the Pacific in 2013/2014 and subsequently the virus spread in other Pacific islands. Threat of explosive global pandemic and severe clinical complications linked with the more immediate and recurrent epidemics necessitate the development of an effective vaccine. Several vaccine platforms such as DNA vaccine, recombinant subunit vaccine, ZIKV purified inactivated vaccine, and chimeric vaccines have shown potent efficacy in vitro and in vivo trials. Moreover, number of drugs such as Sofosbuvir, BCX4450, NITD008 and 7-DMA are ready to enter phase I clinical trial because of proven anti-ZIKV activity. Monoclonal based antibodies offer promise as an intervention effective for use in pregnant women. In this review, we describe the advances in research on ZIKV such as research strategies for the development of antiviral drugs & vaccines, molecular evolution, epidemiology emergence, neurological complications and other teratogenic outcomes as well as pathogenesis.

Zika virus and pregnancy: An overview

In May 2015, the first episodes of Zika virus infection of the Latin America were confirmed in Brazil, where currently 196 976 cases were reported. The main route of transmission occurs by Aedes mosquitoes, and the most common symptoms are maculopapular rash, fever, conjunctivitis, polyarthralgia, and periarticular edema. However, the infection is asymptomatic in 80% of the cases. The congenital infection is characterized when the transmission to the fetus occurs during pregnancy, but the mechanisms of how the virus infects the placenta remain unclear. Anatomopathological findings were described in first- and third-trimester human placentas; however, the major affected tissue of the baby is the neural. Several clinical situations were listed in these fetuses, such as neurological, ophthalmological, auditory, and articular alterations. The World Health Organization proposed a new congenital syndrome caused by Zika virus. The virus has an important neurotropism and the main manifestation observed in the syndrome is microcephaly, which is usually severe and associated with other neurological injuries. The appearance of sudden rash in pregnant women determines immediate investigation through RT-PCR and serological analysis. Moreover, the prevention consists in using repellents and avoiding endemic areas, considering that the vaccine is still under development.

Zika virus: Future reproductive concerns

The pandemic spread of Zika virus (ZIKV), a member of the flavivirus genus of the Flaviviridae family, has become a major public health concern. Reproductive specialists are particularly concerned over the spread of ZIKV as it is now known to have both sexual and transplacental routes of transmission resulting in fetal congenital abnormalities. Other members of the Flaviviridae family, hepatitis C virus (HCV) and bovine viral diarrhea virus (BVDV) (which primarily affects cattle), are well known to reproductive specialists as both sexually transmitted illnesses that are capable of vertical transmission. Congenital infection with BVDV also has a predilection for neuro-teratogenicity as has been seen with ZIKV. HCV and BVDV are also known to be capable of persistent infection in offspring. Could this be the case with ZIKV? Examining what we know about HCV and BVDV, in addition to what we have already learned about ZIKV, may answer some of the questions that remain about ZIKV. Herein, we review the current literature as it pertains to ZIKV vertical transmission and neuro-teratogenicity and compare it to what is known about HCV and BVDV.