Zika virus

A guide for the use of fNIRS in microcephaly associated to congenital Zika virus infection

Congenital Zika Syndrome (CZS) is characterized by changes in cranial morphology associated with heterogeneous neurological manifestations and cognitive and behavioral impairments. In this syndrome, longitudinal neuroimaging could help clinicians to predict developmental trajectories of children and tailor treatment plans accordingly. However, regularly acquiring magnetic resonance imaging (MRI) has several shortcomings besides cost, particularly those associated with childrens' clinical presentation as sensitivity to environmental stimuli. The indirect monitoring of local neural activity by non-invasive functional near-infrared spectroscopy (fNIRS) technique can be a useful alternative for longitudinally accessing the brain function in children with CZS. In order to provide a common framework for advancing longitudinal neuroimaging assessment, we propose a principled guideline for fNIRS acquisition and analyses in children with neurodevelopmental disorders. Based on our experience on collecting fNIRS data in children with CZS we emphasize the methodological challenges, such as clinical characteristics of the sample, desensitization, movement artifacts and environment control, as well as suggestions for tackling such challenges. Finally, metrics based on fNIRS can be associated with established clinical metrics, thereby opening possibilities for exploring this tool as a long-term predictor when assessing the effectiveness of treatments aimed at children with severe neurodevelopmental disorders.

Manifestaciones Oculares Posterior a Infecciones por Arbovirus

Introducción: Las infecciones por virus del Dengue, Chikungunya y Zika se han asociado a manifestaciones oculares como neurorretinitis, vasculitis, coroiditis, coriorretinitis, obstrucción venosa, edema macular, foveolitis, entre otras. Objetivo: El propósito del estudio es presentar una serie de casos de pacientes con afección ocular causada por infecciones por arbovirus. Metodología: Estudio es de carácter descriptivo, retrospectivo, en formato de reporte de serie de casos, describiendo los hallazgos de manifestaciones oculares secundarias a infecciones de arbovirus. Resultados: Se presentaron 13 pacientes con Dengue, 5 con Chikungunya y 4 con Zika. Doce de sexo masculino y diez femenino, con edades que oscilan entre 18 y 62 años. Conclusión: El Dengue es la infección con mayor recurrencia de manifestaciones oculares. El tratamiento con esteroides y anti-VEGF utilizado en base a la evidencia disponible demostró un impacto positivo en la evolución de la agudeza visual. El tratamiento conservador en pacientes con obstrucción de vena central de retina fue efectivo en aquellos que no presentaron la variante isquémica. La atrofia óptica fue la complicación más frecuente y presentó mejoría una vez el cuadro inflamatorio ha sido resuelto.

Zika virus serological diagnosis: commercial tests and monoclonal antibodies as tools

Zika virus (ZIKV), an emerging arthropod-borne virus (arbovirus) of the Flaviviridae family, is a current issue worldwide, particularly because of the congenital and neurological syndromes associated with infection by this virus. As the initial clinical symptoms of all diseases caused by this group are very similar, clinical diagnosis is difficult. Furthermore, laboratory diagnostic efforts have failed to identify specific and accurate tests for each virus of the Flaviviridae family due to the cross-reactivity of these viruses in serum samples. This situation has resulted in underreporting of the diseases caused by flaviviruses. However, many companies developed commercial diagnostic tests after the recent ZIKV outbreak. Moreover, health regulatory agencies have approved different commercial tests to extend the monitoring of ZIKV infections. Considering that a specific and sensitive diagnostic method for estimating risk and evaluating ZIKV propagation is still needed, this review aims to provide an update of the main commercially approved serological diagnostics test by the US Food and Drug Administration (FDA) and Brazilian National Health Surveillance Agency (ANVISA). Additionally, we present the technologies used for monoclonal antibody production as a tool for the development of diagnostic tests and applications of these antibodies in detecting ZIKV infections worldwide.

Dynamics of Zika virus outbreaks: an overview of mathematical modeling approaches

BACKGROUND

The Zika virus was first discovered in 1947. It was neglected until a major outbreak occurred on Yap Island, Micronesia, in 2007. Teratogenic effects resulting in microcephaly in newborn infants is the greatest public health threat. In 2016, the Zika virus epidemic was declared as a Public Health Emergency of International Concern (PHEIC). Consequently, mathematical models were constructed to explicitly elucidate related transmission dynamics.

SURVEY METHODOLOGY

In this review article, two steps of journal article searching were performed. First, we attempted to identify mathematical models previously applied to the study of vector-borne diseases using the search terms "dynamics," "mathematical model," "modeling," and "vector-borne" together with the names of vector-borne diseases including chikungunya, dengue, malaria, West Nile, and Zika. Then the identified types of model were further investigated. Second, we narrowed down our survey to focus on only Zika virus research. The terms we searched for were "compartmental," "spatial," "metapopulation," "network," "individual-based," "agent-based" AND "Zika." All relevant studies were included regardless of the year of publication. We have collected research articles that were published before August 2017 based on our search criteria. In this publication survey, we explored the Google Scholar and PubMed databases.

RESULTS

We found five basic model architectures previously applied to vector-borne virus studies, particularly in Zika virus simulations. These include compartmental, spatial, metapopulation, network, and individual-based models. We found that Zika models carried out for early epidemics were mostly fit into compartmental structures and were less complicated compared to the more recent ones. Simple models are still commonly used for the timely assessment of epidemics. Nevertheless, due to the availability of large-scale real-world data and computational power, recently there has been growing interest in more complex modeling frameworks.

DISCUSSION

Mathematical models are employed to explore and predict how an infectious disease spreads in the real world, evaluate the disease importation risk, and assess the effectiveness of intervention strategies. As the trends in modeling of infectious diseases have been shifting towards data-driven approaches, simple and complex models should be exploited differently. Simple models can be produced in a timely fashion to provide an estimation of the possible impacts. In contrast, complex models integrating real-world data require more time to develop but are far more realistic. The preparation of complicated modeling frameworks prior to the outbreaks is recommended, including the case of future Zika epidemic preparation.

[Zika virus infection: A review]

Zika Virus (ZIKV), originally identified in 1947, is a re-emerging Flavivirus transmitted mainly through bites by Aedes mosquitos. Until the recent outbreaks in the Pacific islands and Central and South America, it was known to cause benign disease, in most cases asymptomatic or with mild and nonspecific symptoms (fever, rash, conjunctivitis, arthralgia, etc.). The unprecedented current epidemic has highlighted new modes of transmission (through blood, perinatally and sexually) as well as serious neurological complications such as congenital defects in the fetuses of infected mothers and Guillain-Barre syndrome in adults. This situation, coupled with the threat of worldwide spread, prompted the WHO to declare the ZIKV a public health emergency of international concern in February 2016.