MedNexus
2022年 · 第04卷第01期
MedNexus
Although significant achievements have shown that the coronavirus disease 2019 (COVID-19) resurgence in Beijing, China, was initiated by contaminated frozen products and transported via cold chain transportation, international travelers with asymptomatic symptoms or false-negative nucleic acid may have another possible transmission mode that spread the virus to Beijing. One of the key differences between these two assumptions was whether the virus actively replicated since, so far, no reports showed viruses could stop evolution in alive hosts. We studied severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequences in this outbreak by a modified leaf-dating method with the Bayes factor. The numbers of single nucleotide variants (SNVs) found in SARS-CoV-2 sequences were significantly lower than those called from B.1.1 records collected at the matching time worldwide (P = 0.047). In addition, results of the leaf-dating method showed ages of viruses sampled from this outbreak were earlier than their recorded dates of collection (Bayes factors > 10), while control sequences (selected randomly with ten replicates) showed no differences in their collection dates (Bayes factors < 10). Our results which indicated that the re-emergence of SARS-CoV-2 in Beijing in June 2020 was caused by a virus that exhibited a lack of evolutionary changes compared to viruses collected at the corresponding time, provided evolutionary evidence to the contaminated imported frozen food should be responsible for the reappearance of COVID-19 cases in Beijing. The method developed here might also be helpful to provide the very first clues for potential sources of COVID-19 cases in the future.
Forecasting the COVID-19 confirmed cases, deaths, and recoveries demands time to know the severity of the novel coronavirus. This research aims to predict all types of COVID-19 cases (verified people, deaths, and recoveries) from the deadliest 3rd wave data of the COVID-19 pandemic in Bangladesh. We used the official website of the Directorate General of Health Services as our data source. To identify and predict the upcoming trends of the COVID-19 situation of Bangladesh, we fit the Auto-Regressive Integrated Moving Average (ARIMA) model on the data from Mar. 01, 2021 to Jul. 31, 2021. The finding of the ARIMA model (forecast model) reveals that infected, deaths, and recoveries number will have experienced exponential growth in Bangladesh to October 2021. Our model reports that confirmed cases and deaths will escalate by four times, and the recoveries will improve by five times at a later point in October 2021 if the trend of the three scenarios of COVID-19 from March to July lasts. The prediction of the COVID-19 scenario for the next three months is very frightening in Bangladesh, so the strategic planner and field-level personnel need to search for suitable policies and strategies and adopt these for controlling the mass transmission of the virus.
The novel betacoronavirus (Severe Acute Respiratory Syndrome Coronavirus 2, SARS-CoV-2) is a pathogen that causes deadly respiratory disease named coronavirus disease 2019 (COVID-19). The incidence of this disease has increased in the last few months affecting 257,832,881 people in 221 countries and 51,68,069 deaths worldwide according to Worldometer at 04:03 GMT on November 22, 2021. Thus, the emergence of this disease creates a challenge for health care providers in handling this pathogen and reducing its risk of transmission. In developing countries, this virus is treated in biosafety level 2 laboratories, where a high concentration of pathogen can easily affect the laboratory staff and cause the spread of this disease. Based on the epidemiology and characteristics of the SARS-CoV-2 virus already discussed in recent studies, we will provide biosafety guidelines and suggestions for safe handling and transportation of the SARS-CoV-2 virus in dealing with the current pandemic situation with a focus on increased infectivity of emerging new variants.
Coronavirus disease 2019 (COVID-19) has rapidly swept around the globe since its emergence near 2020. However, people have failed to fully understand its origin or mutation. Defined as an international biosafety incident, COVID-19 has again encouraged worldwide attention to reconsider the importance of biosafety due to the adverse impact on personal well-being and social stability. Most countries have already taken measures to advocate progress in biosafety-relevant research, aiming to prevent and solve biosafety problems with more advanced techniques and products. Herein, we propose a new concept of biosafety chemistry and reiterate the notion of biosafety materials, which refer to the interdisciplinary integration of biosafety and chemistry or materials. We attempt to illustrate the exquisite association that chemistry and materials science possess with biosafety -science, and we hope to provide a pragmatic perspective on approaches to utilize the knowledge of these two subjects to handle specific biosafety issues, such as detection and disinfection of pathogenic microorganisms, personal protective equipment, vaccine adjuvants and specific drugs, etc.. In addition, we hope to promote multidisciplinary cooperation to strengthen biosafety research and facilitate the development of biosafety products to defend national security in the future.
Due to the increase in human population, habitat destruction, and the close interaction between humans, animals and the environment, these dynamic changes are a threat to the health of human, animal and environment. Therefore, we required intervention consisting of medical, veterinary, environment and other relevant disciplines and sectors in combination. If biological and environmental health is supposed to be optimum, cooperation and coordination is necessary between the multi-sectoral stakeholders responsible for the efforts. It not limits to a region or country on a worldwide scope. One Health encourages a collaborative, coordinated, and multidisciplinary approach to ensure the health and wellbeing of humans, animals, and the environment across different spatial levels, it aims to optimal health for lives and the environment, and recognizing the interconnection between people, animals, plants, and their shared environment. This review discussed the essential to integrate One Health in the areas of infectious diseases, food safety, antimicrobial resistance, ecological environment, and chronic diseases etc., and discuss the practice of One Health in each area with some examples, hoping that One Health will serve as a framework to solve the challenges and issues facing China.
Infection of humans by Powassan virus (POWV) occurs rarely but is potentially life-threatening. First isolated in Ontario, Canada in 1958, the presence of POWV has been confirmed in three countries: Canada, the USA, and Russia. Although a limited number of human cases has been reported thus far, the infection rate has shown signs of increasing during the 21st century. Interestingly, POWV and a genetically close variant, deer tick virus (DTV), are the only member of the tick-borne flaviviruses known to be endemic in North America and maintain in respective tick-host cycles. In this review, we briefly summarize current knowledge involving the epidemiology and etiology, pathogenesis and immunity, molecular evolution, and protein functions of POWV, aiming to increase our understanding of the virus and unlock the potential to control this lethal pathogen. These data may also provide tools to minimize the future threat of other emerging and re-emerging viruses.
The coronavirus disease 2019 (COVID-19) is still causing a wide range of infections and deaths due to the high variability of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Therefore, it is necessary to establish a reliable and convenient pseudovirus-based neutralization assay to develop drug targeted variants of SARS-CoV-2. Based on the HIV-1 backbone, we generated a high titer luciferase (Luc)-expressing pseudovirus packaging system. Three dominant S mutant substitution pseudovirus were also established and identified compared to wide type in hACE2-overexpressing HEK-293T cells (293T-ACE2 cells). Compared to serine protease inhibitor camostat mesylate, the cysteine protease inhibitor E-64d could significantly block all SARS-CoV-2 mutant S pseudovirus infection in 293T-ACE2 cells. Furthermore, the neutralization ability of two antibodies targeted receptor-binding domain (RBD) of SARS-CoV-2 spike protein (S) was evaluated, which showed different inhibition dose-effect curves among four types of S pseudovirus. Overall, we developed a pseudovirus-based neutralization assay for SARS-CoV-2, which would be readily adapted to SARS-CoV-2 variants for evaluating antibodies.
Severe fever with thrombocytopenia syndrome (SFTS), caused by a novel identified bunyavirus SFTS virus (SFTSV), was an emerging viral infectious disease that was firstly reported in China. There are no licensed vaccines and therapeutics against SFTSV currently. B-Propiolactone (BPL) inactivated whole virions of SFTSV strain AH12 were prepared as experimental vaccine in different antigen dose with or without Al(OH)3 adjuvant. The experimental SFTS vaccine was a satisfying immunogen, which could efficiently trigger the development of high levels of SFTSV NP-specific IgG antibodies and neutralizing antibodies against SFTSV Strain HB29 in BALB/c and C57/BL6 mice, and could induce SFTS virus-specific cellular immune responses to a certain extent. A single dose of vaccine was immunogenically insufficient in BALB/c mice; the second and third dose resulted in significant boost in antibody response. The use of Al(OH)3 adjuvant resulted in higher antibody titers. The mediate-dose of vaccine could induce as high and equivalent level of antibody titer as that of high-dose. The experimental SFTS vaccine in mediate-and high antigen dose with adjuvant resulted in solid protection of C57/BL6 mice against wild-type SFTSV challenge with markedly accelerated virus clearance from blood and spleen compared with controls. The experimental SFTS vaccine prepared in this study could efficiently elicit virus specific humoral and cellular immune responses in both BALB/c and C57/BL6 mice, and could protect C57/BL6 mice against SFTS virus challenge. These results supplied evidence that inactivated vaccine was a promising vaccine candidate for the prevention of SFTSV infection.
Avian influenza remains a threat to human wellbeing. Hypochlorite derivatives are commonly used as disinfectants to prevent the spread of the disease. The World Health Organization (WHO) has listed chlorine dioxide (ClO2) as an A1-level, safe, and efficient disinfectant. In this study, we tested the efficacy of ClO2, in aqueous solution and gas forms, against avian influenza A (H7N9) virus. The virus suspension was mixed with ClO2 aqueous solutions of various concentrations and for various time intervals. Aliquots of the mixture were then serially diluted, and the 50% tissue culture infective dose (TCID50) was measured with a hemagglutination test on MDCK cells. ClO2 gas produced from generators was introduced in a chamber containing the virus suspension in a Petri dish. The infective activity of the surviving virus was measured by the hemagglutination test. An aqueous solution of ClO2 at 126 µg/mL for 15 s was effective given that no surviving virus was detected with the hemagglutination test. ClO2 gas at >5 µL/L sustained for 1 h inactivated the virus effectively, while at 2.5 µL/L for 1 h, it only partially inactivated the virus. ClO2 as gas or aqueous solution at a certain concentration is effective in inactivating the H7N9 virus, and can be applied for the decontamination and disinfection of environments.
本期目次
