ABSTRACT
Viral infectious diseases may cause neurological symptoms primarily in two nonexclusive ways. Infection may lead to an excessive inflammatory response that damages the neuronal system, which is referred to as immunopathology, or the pathogen is able to infect brain cells, such as neurons or nonneuronal glial cells, like oligodendrocytes, microglia, and astrocytes. Viruses that target and infect cells of the CNS, in general, are called neurotropic. 3D brain organoids provide favorable conditions to study target cells and induced pathomechanisms associated with such viral neurotropism. In the context of highly pathogenic viruses, strict safety precautions (safety level-3 laboratory) must be taken if infectious laboratory strains or strains from clinical samples are to be used for infection experiments. Likewise, safe inactivation protocols must be used for subsequent analysis. This chapter will discuss appropriate protocols, focusing on methodological aspects for each of these steps, and discuss advantages and disadvantages when working with 3D brain organoids while handling biosafety level-3 pathogens based on our work with severe acute respiratory virus type 2 (SARS-CoV-2). Copyright © 2023, Springer Science+Business Media, LLC, part of Springer Nature.
ABSTRACT
Background. Sharp declines in influenza and respiratory syncytial virus (RSV) circulation across the U.S. have been described during the pandemic in temporal association with community mitigation for control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We aimed to determine relative frequencies of rhinovirus/ enterovirus (RV/EV) and other respiratory viruses in children presenting to emergency departments or hospitalized with acute respiratory illness (ARI) prior to and during the COVID-19 pandemic. Methods. We conducted a multi-center active prospective ARI surveillance study in children as part of the New Vaccine Surveillance Network (NVSN) from December 2016 through January 2021. Molecular testing for RV/EV, RSV, influenza, and other respiratory viruses [i.e., human metapneumovirus, parainfluenza virus (Types 1-4), and adenovirus] were performed on specimens collected from children enrolled children. Cumulative percent positivity of each virus type during March 2020-January 2021 was compared from March-January in the prior seasons (2017-2018, 2018-2019, 2019-2020) using Pearson's chi-squared. Data are provisional. Results. Among 69,403 eligible children, 37,676 (54%) were enrolled and tested for respiratory viruses. The number of both eligible and enrolled children declined in early 2020 (Figure 1), but 4,691 children (52% of eligible) were enrolled and tested during March 2020-January 2021. From March 2020-January 2021, the overall percentage of enrolled children with respiratory testing who had detectable RV/EV was similar compared to the same time period in 2017-2018 and 2019-2020 (Figure 1, Table 1). In contrast, the percent positivity of RSV, influenza, and other respiratory viruses combined declined compared to prior years, (p< 0.001, Figure 1, Table 1). Figure 1. Percentage of Viral Detection Among Enrolled Children Who Received Respiratory Testing, New Vaccine Surveillance Network (NVSN), United States, December 2016 - January 2021 Table 1. Percent of Respiratory Viruses Circulating in March 2020- January 2021, compared to March-January in Prior Years, New Vaccine Surveillance Network (NVSN), United States, March 2017 - January 2021 Conclusion. During 2020, RV/EV continued to circulate among children receiving care for ARI despite abrupt declines in other respiratory viruses within this population. These findings warrant further studies to understand virologic, behavioral, biological, and/or environmental factors associated with this continued RV/EV circulation.