2020年 · 第02卷第03期

The non-specific beneficial effects of Bacille Calmette-Guérin (BCG) vaccination suggest that this vaccine might play a role in protecting individuals against severe coronavirus disease 2019 (COVID-19). Several studies propose that BCG vaccination may increase the body's immunity, thereby preventing respiratory infections caused by other respiratory pathogens. As the number of deaths due to COVID-19 is increasing rapidly and there is no specific treatment available to date, scientists are evaluating the effectiveness of already approved drugs as therapies against COVID-19, and the results were found to vary widely: from no significant effect being observed to a reduction in the time taken for clinical improvement. This study thus aims to evaluate whether it is worth performing clinical trials to examine the effects of the BCG vaccine on COVID-19. We herein emphasize the need to conduct phase III randomized controlled trials with adequate sample size and quality to investigate the effects of the BCG vaccine on COVID-19. In the event that BCG vaccination provides non-specific protection against COVID-19, administering it could be helpful in controlling the transmission of COVID-19 and other infectious diseases during future pandemics.

Vaccination is currently the most effective way to protect against influenza viruses. This study presents PREDAC (PRE-Dict Antigenic Cluster), a sequence-based computational method to model antigenic clusters of influenza viruses. PREDAC could improve vaccine recommendations for influenza viruses and has been used to support the influenza vaccine strain recommendations at the Chinese National Influenza Center. Moreover, a PREDAC server which includes tools for the prediction of antigenic variants and antigenic clusters of both influenza A and B viruses was built and made publicly available at http://www.computationalbiology.cn/home/. PREDAC could not only facilitate systematic studies of the antigenic evolution of influenza viruses but also provide user-friendly tools for vaccine strain recommendations for influenza viruses.

This study presents the structure and application of dunk tanks in high-level biosafety laboratories. The test methods and sterilization effects of dunk tanks were evaluated by using Bacillus subtilis as indicator. Results showed that sterilization effects of dunk tanks could be achieved by immersing the goods in 0.5% sodium hypochlorite disinfectant solution for 30 min at room temperature. Neutralizer sodium thiosulfate had no effect on the growth of Bacillus subtilis, and thus would not affect the disinfection results of sodium hypochlorite. Furthermore, suggestions for safe operation of dunk tanks are also provided in this study.

This paper summarized the pressure control methods used in 16 large-scale production facilities in China for vaccines against foot-and-mouth disease virus and highly pathogenic avian influenza virus. We presented the pressure control modes, with their characteristics, of the "constant supply" mode - variable exhaust air volume system and the "constant supply" mode - constant exhaust air volume system. This paper analyzed the influence of common problems (e.g., pressure reference zero drift, positive pressure reversal and failure to restore the original normal working conditions after working condition conversion) on system stability during pressure control in BSL-3 large-scale production facilities and their solutions, providing references for the design and implementation of similar construction projects under the new situation.

Group A Streptococcus (GAS; Streptococcus pyogenes) is one of the most versatile bacteria among human pathogens. Non-invasive GAS infections can cause common diseases, such as pharyngitis and impetigo. Severe invasive GAS infections can lead to rapid progressive and life-threatening manifestations, including necrotizing fasciitis and streptococcal toxic shock syndrome with high mortality rates ranging from 30% to 70%. Therefore, GAS is also known as "killer microbes" or "flesh-eating bacteria" . During severe invasive GAS infections, anti-bacterial immunity is impeded by attenuation of the cellular components of innate immune responses. However, this loss of protection is compensated for by interferon-γ-producing immature myeloid cells, which are recruited upon severe invasive GAS infections in mouse models. In this review, we discuss and summarize the current knowledge on the role of interferon-γ-producing myeloid cells and other myeloid cells in the prevention and control of severe invasive GAS infections.

Tuberculosis (TB) is a chronic infectious respiratory disease caused by Mycobacterium tuberculosis (MTB), which seriously endangers human health. TB is transmitted through the respiratory tract and poses great biosafety risks to laboratory technicians and staff, through direct or indirect contact with MTB. Therefore, the comprehensive application of standard laboratory operating procedures, safety equipment, contingency plans, and other laboratory biosafety measures not only ensures the safe handling of potentially infectious microorganisms by laboratory workers but also strives to prevent the accidental exposure of potentially harmful pathogens to larger communities. In this article, we intend to discuss topics as biosafety risk assessments suitable for handling the biohazard levels of MTB strains, and the development of corresponding biosafety protection measures necessary for the biosafety of MTB testing and related research that will be implemented at different levels of laboratory and epidemiological situation.

Porcine endogenous retroviruses (PERVs) are proviruses that have medical value in xenotransplantation. However, the evolutionary process leading to the generation of modern PERVs is not well understood. In this study, we in silico mined 14 pig genomes and other available 304 mammalian genomes, which led to the documentation of 185 full-length PERVs or PERV-like sequences. Notably, we found that lesser Egyptian jerboa (Jaculus jaculus), rock hyrax (Procavia capensis) and eight Muridae species all harbored ancestral PERV-like sequences, indicative of ancient cross-species transmission events from none-porcine species to pigs. We also revealed that 11 genomic rearrangement events were mediated via PERVs, during the process of porcine evolution. In conclusion, these new findings help us to understand the complex evolution of the modern PERVs.

Wenzhou virus (WENV) was first identified in rodents and Asian house shrews in Wenzhou, Zhejiang Province, China. However, little is known about the prevalence of WENV infections in humans in China. To determine the threat that WENV may pose to humans, we determine the seroprevalence of WENV in healthy individuals in China in this study. Cross-reactivities of nucleoprotein (NP) were detected between Lymphocytic choriomeningitis virus (LCMV) and WENV using Western blot and ELISA assy. The prevalence of specific IgG antibodies against WENV NP was investigated in different age groups of 830 healthy individuals aged 0-70 years old in China using a competition ELISA assay. The results indicate that WENV and LCMV share cross-reactive epitopes between NPs. The total seroprevalence of WENV in healthy adults was 4.6%, with 3.6% (8/221) for individuals 15-44 years of age, 5.4% (17/317) for individuals 45-59 years of age, and 4.1% (4/98) for older adults over 60. The total seroprevalence of WENV in children under age 15 was 1.5%, with 2.9% (1/34) in children aged 2-5 years, and 2.2% in 5-14 years (2/91). The finding suggests that WENV or WENV-like virus may sporadically infect humans of China.

Rabies virus (RABV) phosphoprotein (P) plays an important role in disrupting host interferon (IFN)-mediated antiviral immune response. ABCE1 is known as an RNase L inhibitor that negatively regulates the 2′,5′-oligoadenylate (2-5A)/RNase L antiviral system related to the IFN signaling pathway. In this study, we screened the host factors associated with RABV P protein, while focusing on ABCE1 because of its role in the life cycle of several viruses. Our results showed that knockout of ABCE1 in HEK293T cells inhibited RABV replication. In contrast, the overexpression of ABCE1 in HEK293T cells enhanced RABV replication. Notably, the co-immunoprecipitation assay showed that ABCE1 interacted with RABV P protein. Since ABCE1 and RABV P proteins are related to the IFN signaling pathway, we propose that the interaction of viral P protein with ABCE1 leads to the disruption of host antiviral immune response. In summary, our research showed that ABCE1 is an important host protein that interacts with viral P protein and regulates RABV replication. Moreover, the interaction between ABCE1 and RABV P protein may facilitate the viral P protein-mediated disruption of host antiviral immune response.

This study described the epidemiologic and clinical characteristics of patients who died from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and pointed out the potential risk factors associated with fatal outcomes. Retrospective data from 42 death cases due to SARS-CoV-2 infection at Tongji Hospital Affiliated to Huazhong University of Science and Technology, Wuhan, China was analyzed. Demographics, clinical detection, laboratory findings, and treatments of the deceased were collected and analyzed. The average time between onset of symptoms and admission to the hospitals was 11 ± 5 days of hospitalization. Among the deceased, 60% were with co-morbidities. All of them were having fever and bilateral pneumonia on computed tomography, abnormal infection-related biomarkers, and renal impairment. Abnormal blood coagulation parameters that appeared in more than half of them, were consistent with disseminated intravascular coagulation. All of the patients were treated in the ICU. Based on the fact that SARS-CoV-2 infection carries a risk of mortality, we may infer a few older male patients with underlying comorbidities are likely to have the increased risk. Impaired consciousness level, markers of renal impairment and coagulation abnormalities may be poor prognostic factors.

The incidences of nosocomial infections (NIs) are increasing throughout the world, especially for those airborne diseases caused by pathogens or air particulates that float in air. In this study, we designed and manufactured a desk for clinic consultation room air purification and air isolation between doctor and patient. The air isolation and purification (AIP) desk has a high efficiency particulate air (HEPA) filter on the tope and several primary efficiency filters on the sides for air purification. The air circulating between inlet and outlet forms a wind-curtain between doctor and patient. The Computational Fluid Dynamics (CFD) model was used to calculate the speed of the air flow and the angle of sampler. We tested the air purification function of the AIP desk in rooms sized about 3.6 × 2.8 × 2.8 m (L × W × H) and found that the AIP desk could significantly remove the tested air pollutants like smoke particulates and microorganisms like Staphylococcus albus (S. albus)and human adenovirus type 5 (HAdV-5). The wind-curtain can significantly block the exhale air of patient being transmitted to the respiratory area of doctor setting in the opposite of AIP desk. Thus, the AIP desk can be used in hospital setting to reduce the risk of NIs and protect both doctors and patients.

Infectious agents, both standard and emerging or engineered, might initiate outbreaks with global impact and/or existential-level threat potential. Such agents might infect human, livestock, exploitable plant cultures or the environment at large. Instead of responding by sampling teams which may also carry out prolonged surveillance, a more effective concept is to pre-process the samples, possibly to nucleic acid extract so as to transport them without biological risks by standard channels, or to process them up to a point and return the results, leaving the samples which only need specialized tests and dedicated equipment. In this context a portable device, allowing multiple routine and crisis-management applications due to its inherent flexibility, is scrutinized against alternatives and possible needs so as to develop a novel standard of surveillance and intervention, meant to facilitate containment by providing faster much more reliable laboratory results at a fraction of older generation mobile nucleic acids analyzers. Additional steps, such as agarose in pills and buffers pre-packaged in expendable syringes with pistons locked by improvised safety features may improve the Complexity Level of the whole system so as to make it appealing to intervention/crisis management personnel, while the instrument proper may double as backup for respective benchtop devices.