Emerging coronaviruses: Genome structure, replication, and pathogenesis

High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa

It has been reported that ACE2 is the main host cell receptor of 2019-nCoV and plays a crucial role in the entry of virus into the cell to cause the final infection. To investigate the potential route of 2019-nCov infection on the mucosa of oral cavity, bulk RNA-seq profiles from two public databases including The Cancer Genome Atlas (TCGA) and Functional Annotation of The Mammalian Genome Cap Analysis of Gene Expression (FANTOM5 CAGE) dataset were collected. RNA-seq profiling data of 13 organ types with para-carcinoma normal tissues from TCGA and 14 organ types with normal tissues from FANTOM5 CAGE were analyzed in order to explore and validate the expression of ACE2 on the mucosa of oral cavity. Further, single-cell transcriptomes from an independent data generated in-house were used to identify and confirm the ACE2-expressing cell composition and proportion in oral cavity. The results demonstrated that the ACE2 expressed on the mucosa of oral cavity. Interestingly, this receptor was highly enriched in epithelial cells of tongue. Preliminarily, those findings have explained the basic mechanism that the oral cavity is a potentially high risk for 2019-nCoV infectious susceptibility and provided a piece of evidence for the future prevention strategy in dental clinical practice as well as daily life.

High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa

It has been reported that ACE2 is the main host cell receptor of 2019-nCoV and plays a crucial role in the entry of virus into the cell to cause the final infection. To investigate the potential route of 2019-nCov infection on the mucosa of oral cavity, bulk RNA-seq profiles from two public databases including The Cancer Genome Atlas (TCGA) and Functional Annotation of The Mammalian Genome Cap Analysis of Gene Expression (FANTOM5 CAGE) dataset were collected. RNA-seq profiling data of 13 organ types with para-carcinoma normal tissues from TCGA and 14 organ types with normal tissues from FANTOM5 CAGE were analyzed in order to explore and validate the expression of ACE2 on the mucosa of oral cavity. Further, single-cell transcriptomes from an independent data generated in-house were used to identify and confirm the ACE2-expressing cell composition and proportion in oral cavity. The results demonstrated that the ACE2 expressed on the mucosa of oral cavity. Interestingly, this receptor was highly enriched in epithelial cells of tongue. Preliminarily, those findings have explained the basic mechanism that the oral cavity is a potentially high risk for 2019-nCoV infectious susceptibility and provided a piece of evidence for the future prevention strategy in dental clinical practice as well as daily life.

Systematic Comparison of Two Animal-to-Human Transmitted Human Coronaviruses: SARS-CoV-2 and SARS-CoV

After the outbreak of the severe acute respiratory syndrome (SARS) in the world in 2003, human coronaviruses (HCoVs) have been reported as pathogens that cause severe symptoms in respiratory tract infections. Recently, a new emerged HCoV isolated from the respiratory epithelium of unexplained pneumonia patients in the Wuhan seafood market caused a major disease outbreak and has been named the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This virus causes acute lung symptoms, leading to a condition that has been named as "coronavirus disease 2019" (COVID-19). The emergence of SARS-CoV-2 and of SARS-CoV caused widespread fear and concern and has threatened global health security. There are some similarities and differences in the epidemiology and clinical features between these two viruses and diseases that are caused by these viruses. The goal of this work is to systematically review and compare between SARS-CoV and SARS-CoV-2 in the context of their virus incubation, originations, diagnosis and treatment methods, genomic and proteomic sequences, and pathogenic mechanisms.

Initial CT findings and temporal changes in patients with the novel coronavirus pneumonia (2019-nCoV): a study of 63 patients in Wuhan, China

Objectives

The purpose of this study was to observe the imaging characteristics of the novel coronavirus pneumonia.

Methods

Sixty-three confirmed patients were enrolled from December 30, 2019 to January 31, 2020. High-resolution CT (HRCT) of the chest was performed. The number of affected lobes, ground glass nodules (GGO), patchy/punctate ground glass opacities, patchy consolidation, fibrous stripes and irregular solid nodules in each patient's chest CT image were recorded. Additionally, we performed imaging follow-up of these patients.

Results

CT images of 63 confirmed patients were collected. M/F ratio: 33/30. The mean age was 44.9 ± 15.2 years. The mean number of affected lobes was 3.3 ± 1.8. Nineteen (30.2%) patients had one affected lobe, five (7.9%) patients had two affected lobes, four (6.3%) patients had three affected lobes, seven (11.1%) patients had four affected lobes while 28 (44.4%) patients had 5 affected lobes. Fifty-four (85.7%) patients had patchy/punctate ground glass opacities, 14 (22.2%) patients had GGO, 12 (19.0%) patients had patchy consolidation, 11 (17.5%) patients had fibrous stripes and 8 (12.7%) patients had irregular solid nodules. Fifty-four (85.7%) patients progressed, including single GGO increased, enlarged and consolidated; fibrous stripe enlarged, while solid nodules increased and enlarged.

Conclusions

Imaging changes in novel viral pneumonia are rapid. The manifestations of the novel coronavirus pneumonia are diverse. Imaging changes of typical viral pneumonia and some specific imaging features were observed. Therefore, we need to strengthen the recognition of image changes to help clinicians to diagnose quickly and accurately.

Key Points

• High-resolution CT (HRCT) of the chest is critical for early detection, evaluation of disease severity and follow-up of patients with the novel coronavirus pneumonia.

• The manifestations of the novel coronavirus pneumonia are diverse and change rapidly.

• Radiologists should be aware of the various features of the disease and temporal changes.

Estimation of the Transmission Risk of the 2019-nCoV and Its Implication for Public Health Interventions

Since the emergence of the first cases in Wuhan, China, the novel coronavirus (2019-nCoV) infection has been quickly spreading out to other provinces and neighboring countries. Estimation of the basic reproduction number by means of mathematical modeling can be helpful for determining the potential and severity of an outbreak and providing critical information for identifying the type of disease interventions and intensity. A deterministic compartmental model was devised based on the clinical progression of the disease, epidemiological status of the individuals, and intervention measures. The estimations based on likelihood and model analysis show that the control reproduction number may be as high as 6.47 (95% CI 5.71-7.23). Sensitivity analyses show that interventions, such as intensive contact tracing followed by quarantine and isolation, can effectively reduce the control reproduction number and transmission risk, with the effect of travel restriction adopted by Wuhan on 2019-nCoV infection in Beijing being almost equivalent to increasing quarantine by a 100 thousand baseline value. It is essential to assess how the expensive, resource-intensive measures implemented by the Chinese authorities can contribute to the prevention and control of the 2019-nCoV infection, and how long they should be maintained. Under the most restrictive measures, the outbreak is expected to peak within two weeks (since 23 January 2020) with a significant low peak value. With travel restriction (no imported exposed individuals to Beijing), the number of infected individuals in seven days will decrease by 91.14% in Beijing, compared with the scenario of no travel restriction.

COVID-19 from mysterious enemy to an environmental detection process: a critical review

The recent global emergence of an unusual viral pneumonia of COVID-19 epidemic was firstly started in Wuhan city, Hubei province in China in December 2019. Regrettably, it is still sweeping the planet, and it cannot be controlled up till now. By May 2020, the unexpected spread of this disaster had caused more than 3,759,967 cases and 259,474 deaths in 114 countries from Asia to the Middle East, Europe, and the USA. Considering its fatal nature, it has evolved as a major challenge for the world. This is necessitating a quick and steep intervention in order to save millions of people’s lives across the globe. The knowledge about the nature and evolution of the COVID-19 virus in water, soils, and other environmental compartments can be addressed through wastewater and sewage. Wastewater-based epidemiology approach can be used as an early indicator of the infection within a specific population. The basic aim of this review article is trying to provide a prompt, and valuable reference guides about COVID-19. Some important questions were addressed, such as, its origin, transmission, clinical symptoms, diagnosis, environmental aspects, and the possible indoors and outdoors airborne transmission minimization strategies that may benefit specialists.

COVID-19, Virology and Geroscience: A Perspective

A new coronavirus, called SARS-CoV-2, was identified in Wuhan, China, in December 2019. The SARS-CoV-2 spread very rapidly, causing a global pandemic, Coronavirus Disease 2019 (COVID-19). Older adults have higher peak of viral load and, especially those with comorbidities, had higher COVID-19-related fatality rates than younger adults. In this Perspective paper, we summarize current knowledge about SARS-CoV-2 and aging, in order to understand why older people are more affected by COVID-19. We discuss about the possibility that the so-called "immunosenescence" and "inflammaging" processes, already present in a fraction of frail older adults, could allow the immune escape of SARS-CoV-2 leading to COVID-19 serious complications. Finally, we propose to use geroscience approaches to the field of COVID-19.

Lockdown of colleges and universities due to COVID-19: Any impact on the educational system in India?

Pneumonia triggered by novel corona virus (SARS-CoV-2) in Wuhan, China, in December 2019 is an extremely contagious disease. The WHO has stated the outbreak of COVID-19 (corona virus) as a pandemic issue. Corona virus cases started increasing day by day in India, also from the time the first case was diagnosed on January 30, 2020. In this regard, there are so many colleges and universities across India which cancelled or rescheduled their academic activities such as conferences, workshops, and other academic and sports activities. Because the universities and colleges should protect and take care of their students and faculty in this regard. In this brief communication, I would like to give an idea on the potential impact of the dangerous COVID-19 outbreak on the education system and mental health of students and staff.

Coronavirus disease 2019 (COVID-19): diagnosis and prognosis

Coronavirus disease 2019 (COVID-19) has become a global pandemic with a high rate of transmission. Currently, there is a lack of vaccines and specific drugs for this newly-emerged virus. Timely diagnosis and treatment, as well as isolation of patients and virus carriers, contribute to the effective prevention and control of this epidemic. This review focuses on early stage COVID-19 diagnosis methods and strategies, highlighting the guiding role of laboratory indicators on treatment strategy formulation, and prognosis assessments.

Screening marine algae metabolites as high-affinity inhibitors of SARS-CoV-2 main protease (3CLpro): an in silico analysis to identify novel drug candidates to combat COVID-19 pandemic

The recent dissemination of SARS-CoV-2 from Wuhan city to all over the world has created a pandemic. COVID-19 has cost many human lives and created an enormous economic burden. Although many drugs/vaccines are in different stages of clinical trials, still none is clinically available. We have screened a marine seaweed database (1110 compounds) against 3CLpro of SARS-CoV-2 using computational approaches. High throughput virtual screening was performed on compounds, and 86 of them with docking score <  - 5.000 kcal mol^-1 were subjected to standard-precision docking. Based on binding energies (< - 6.000 kcal mol^-1), 9 compounds were further shortlisted and subjected to extra-precision docking. Free energy calculation by Prime-MM/GBSA suggested RC002, GA004, and GA006 as the most potent inhibitors of 3CLpro. An analysis of ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) properties of RC002, GA004, and GA006 indicated that only RC002 (callophysin A, from red alga Callophycus oppositifolius) passed Lipinski's, Veber's, PAINS and Brenk's filters and displayed drug-like and lead-like properties. Analysis of 3CLpro-callophysin A complex revealed the involvement of salt bridge, hydrogen bonds, and hydrophobic interactions. callophysin A interacted with the catalytic residues (His41 and Cys145) of 3CLpro; hence it may act as a mechanism-based competitive inhibitor. Docking energy and docking affinity of callophysin A towards 3CLpro was - 8.776 kcal mol^-1 and 2.73 × 10⁶ M^-1, respectively. Molecular dynamics simulation confirmed the stability of the 3CLpro-callophysin A complex. The findings of this study may serve as the basis for further validation by in vitro and in vivo studies.

Neutrophil count to albumin ratio as a new predictor of mortality in patients with COVID-19 ınfection

SUMMARY BACKGROUND Coronavirus Disease 2019 is an acute inflammatory respiratory disease. It causes many changes in hemogram parameters. Low albumin levels are associated with mortality risk in hospitalized patients. The aim of the present study is to reveal the place of neutrophil count to albumin ratio in predicting mortality in patients with COVID-19. METHODS 144 patients, 65 females and 79 males, were included in the study. Patients were divided into 2 groups. Group 1 was the non-severe group (n:85), and Group 2 was severe (n:59). Demographic data, neutrophil, lymphocyte and platelet counts, albumin and C-reactive protein (CRP) levels were recorded. Neutrophil count to albumin ratio (NAR) was calculated by dividing the absolute neutrophil counts by the albumin levels. The NAR and levels of the two groups were then compared. RESULTS There were no significant differences in gender and platelet count (201 vs. 211 K/mL) between the groups (p>0,05). Ages (62.0 ± 14.3 vs 68.6 ± 12.2 years), albumin (33.1 vs 29.9 gr/L), CRP (33 vs 113 mg/l), neutrophil count (4 vs 7.24 K/mL), WBC counts (6.70 vs 8.50 K/mL), NAR values (113.5 vs 267.2) and number of Death (5 vs 33) were found to be statistically higher (p <0.001) in Group 2 than in Group 1. The NAR value of 201.5 showed mortality in all patients with COVID-19 to have 71.1% sensitivity and 71.7% specificity (AUC:0.736, 95% CI: 0.641-0.832, p<0.001) CONCLUSION The present study showed that NAR levels can be a cheap and simple marker for predicting mortality in patients with COVID-19.

Knowledge and awareness on novel coronavirus spread among dental fraternities in Visakhapatnam, India: A questionnaire-based survey

INTRODUCTION

The pandemic caused by novel coronavirus (severe acute respiratory syndrome coronavirus 2) in Wuhan, China, in December 2019 is a highly contagious disease. The World Health Organization has declared the outbreak of coronavirus diseases (COVID-19) as a global public health emergency. Currently, the research on novel coronavirus is still in the primary stage. The aim of this study is to assess the knowledge and awareness on COVID-19 disease and related infection control measures among the dental fraternity in Visakhapatnam - the smart city.

METHODS

A total of 808 dentists from the Visakhapatnam region completed a questionnaire-based survey on the knowledge, awareness, and infection control measures related to COVID-19 infection. The questionnaire was tailored from the guidance and information for health-care workers issued by the US Centers for Disease Control and Prevention. Suitable sampling method was used for the collection of data and the distribution of responses was presented as percentages. Explanatory statistics were performed for all groups and subgroups based on the percentage of correct responses. Individual pair-wise comparisons were done using the Chi-square test for the percentage of correct responses.

RESULTS

A total of 825 participated in the survey, of which 808 dentists completely answered the survey, and the response rate was 98%. Among the respondents, males and females are 46.8% and 53.2%, respectively. There was a statistically significant difference for all the questions solicited, among age groups (P = 0.001, 0.001) and occupation (P = 0.001, 0.001, 0.004). Private practitioners seem to more awareness compared to teaching faculty, undergraduates, and postgraduates, as they have answered correctly (>70%) for almost all the questions.

CONCLUSION

The inputs from the survey help us throw some light and fill up lacunae where required. There is a strong need to implement periodic educational interventions and training programs on infection control practices for COVID-19 among dentists in particular. The information from this survey helps us to make necessary changes in implementing periodic educational webinars and stress on areas where necessary, which is important for the dental fraternity for protecting themselves and shielding our society from COVID-19.

Severity Detection for the Coronavirus Disease 2019 (COVID-19) Patients Using a Machine Learning Model Based on the Blood and Urine Tests

The recent outbreak of the coronavirus disease-2019 (COVID-19) caused serious challenges to the human society in China and across the world. COVID-19 induced pneumonia in human hosts and carried a highly inter-person contagiousness. The COVID-19 patients may carry severe symptoms, and some of them may even die of major organ failures. This study utilized the machine learning algorithms to build the COVID-19 severeness detection model. Support vector machine (SVM) demonstrated a promising detection accuracy after 32 features were detected to be significantly associated with the COVID-19 severeness. These 32 features were further screened for inter-feature redundancies. The final SVM model was trained using 28 features and achieved the overall accuracy 0.8148. This work may facilitate the risk estimation of whether the COVID-19 patients would develop the severe symptoms. The 28 COVID-19 severeness associated biomarkers may also be investigated for their underlining mechanisms how they were involved in the COVID-19 infections.

Study and overview of the novel corona virus disease (COVID-19)

In December 2019, a new disease with pneumonia-like symptoms was spreading throughout Wuhan in China which was entitled as novel coronavirus disease or COVID -19 caused by the virus SARS CoV-2. Within a span of a few days, this disease became a global threat and was termed as a pandemic by the World Health Organization (WHO) on March 11, 2020, since then the disease has affected more than 1.5 crore people worldwide and around 6.9 lakh people in India as of July 5, 2020. The origin of the COVID-19 disease has been traced back to the bats, but the intermediary contact is unknown. The disease spreads by respiratory droplets and contaminated surfaces. In most cases, the virus shows mild symptoms like fever, fatigue, dyspnea, cough, etc. which may become severe if appropriate precautions are not adhered to. For people with comorbidities (usually elderly) the disease may turn deadly and cause pneumonia, Acute Respiratory Disease Syndrome (ARDS), and multi-organ failure, thereby affecting a person's ability to breathe leading to being put on the ventilator support. The reproduction number (Rℴ) of COVID-19 is much higher than its predecessors and genetically similar diseases like SARS-CoV and MERS-CoV. This paper discusses the epidemiological characteristics of the SARS-CoV-2 virus, its phylogenetic relationship with the previous pandemic causing viruses such as SARS-CoV-1 and MERS-CoV and analyzes the various responses to this global pandemic worldwide, focusing on the actions taken by India and their outcomes.

Review of Sterilization Techniques for Medical and Personal Protective Equipment Contaminated With SARS-CoV-2

The outbreak of the novel coronavirus disease, COVID-19 turned into a global pandemic in March 2020. During these unprecedented times, there is an increased demand in medical and personal protective equipment (PPE). Since the supplies may take a long time to meet the global demand, reusing PPEs will help health care workers in their response to the COVID-19 pandemic. To ensure the safety and well-being of the medical first responders, PPE needs to be sterilized before reuse. In this review, we examine various sterilization techniques that can be used to sterilize PPEs and point out its limitations. The objective is to provide a foundation of knowledge incorporating different sterilization techniques that allow hospitals and clinics to pick the most suitable technique for sterilization of a particular PPE.

Antiviral agents against COVID-19: structure-based design of specific peptidomimetic inhibitors of SARS-CoV-2 main protease

Despite the intense development of vaccines and antiviral therapeutics, no specific treatment of coronavirus disease 2019 (COVID-19), caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently available. Recently, X-ray crystallographic structures of a validated pharmacological target of SARS-CoV-2, the main protease (M^pro also called 3CL^pro) in complex with peptide-like irreversible inhibitors have been published. We have carried out computer-aided structure-based design and optimization of peptidomimetic irreversible α-ketoamide M^pro inhibitors and their analogues using MM, MD and QM/MM methodology, with the goal to propose lead compounds with improved binding affinity to SARS-CoV-2 M^pro, enhanced specificity for pathogenic coronaviruses, decreased peptidic character, and favourable drug-like properties. The best inhibitor candidates designed in this work show largely improved interaction energies towards the M^pro and enhanced specificity due to 6 additional hydrogen bonds to the active site residues. The presented results on new SARS-CoV-2 M^pro inhibitors are expected to stimulate further research towards the development of specific anti-COVID-19 drugs.

Structure-based design of SARS-CoV-2 main protease inhibitors identified hydantoin, benzothiazine and cresol moieties as promising residues of new peptidomimetic inhibitors.

Classical Coronaviruses

In the last week of December 2019, few patients with the history of pyrexia of unknown origin and symptoms of lower respiratory tract infections were detected in Wuhan, a well-known area as the largest metropolitan city located in the province of Hubei, China. On further investigation, a novel coronavirus was identified as the causative pathogen, which later on provisionally named as 2019 novel coronavirus (2019-nCoV). Coronaviruses are predominantly found in warm-blooded animals and birds and cause various respiratory complications and multiorgan failure in the immunocompromised individuals. Human coronaviruses were first identified in 1965 and are responsible for the respiratory tract infections in major proportion of population worldwide; at least five new human coronaviruses have been identified, including severe acute respiratory syndrome coronavirus (SARS-CoV) in 2002–2003 and Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012. The background related to the origin and classification of coronaviruses is reviewed here.

Histopathologic Findings of Coronavirus in Lung: A Mini-Review

Coronaviruses (CoVs) are important human and animal pathogens. There have been several outbreaks of lung involvement by this category of viruses in the world, ie, severe acute respiratory syndrome (SARS-CoV-1) in 2002 and 2003, the Middle East respiratory syndrome (MERS-CoV) in 2012, and the new coronavirus (2019-nCoV) outbreak of pneumonia from Wuhan, China, since December 2019. There have been several studies about the clinical features and imaging features, but very few reports have been published about pathologic findings in lung tissue, which was partly because of the lack of tissue diagnosis secondary to suddenness of the outbreak. Overall, less than 30 reports have been published in the literature about histologic findings of lung in these viruses, so far. In this report, we will review the published reports about the histopathologic findings of lung tissue in the patients infected with SARS-CoV-2 in comparison with 2 other coronaviruses that have caused outbreaks, ie, SARS-CoV-1 and MERS-CoV.

Current understanding, knowledge gaps and a perspective on the future of COVID-19 Infections: A systematic review

A novel coronavirus infection, which began as an outbreak of unusual viral pneumonia in Wuhan, a central city in China, has evolved into a global health crisis. The outbreak is an unembellished reminder of the hazard coronaviruses pose to public health. Government and researchers around the world have been taking swift measures to control the outbreak and conduct aetiological studies to understand the various facets of the outbreak. This review is an attempt at providing an insight about the current understanding, knowledge gaps and a perspective on the future of coronavirus disease 2019 (COVID-19) infections. All the authentic data published so far on COVID-19 has been systematically analysed. PubMed, NCBI, World Health Organisation, Ministry of Health and Family Welfare (India), and Centers for Disease Control and Prevention databases and bibliographies of relevant studies up to 22nd June 2020 have been included. The Wuhan outbreak is a stark reminder of the continuing threat posed by zoonotic diseases to global health. Despite an armamentarium of Government officials, researchers and medical fraternity working towards the containment of this novel coronavirus viral pneumonia continues to spread at an alarming rate infecting multitudes and claiming hundreds of lives.

Clinical and radiological features of novel coronavirus pneumonia

Recently, COVID-19 has spread in more than 100 countries and regions around the world, raising grave global concerns. COVID-19 transmits mainly through respiratory droplets and close contacts, causing cluster infections. The symptoms are dominantly fever, fatigue, and dry cough, and can be complicated with tiredness, sore throat, and headache. A few patients have symptoms such as stuffy nose, runny nose, and diarrhea. The severe disease can progress rapidly into the acute respiratory distress syndrome (ARDS). Reverse transcription polymerase chain reaction (RT-PCR) and Next-generation sequencing (NGS) are the gold standard for diagnosing COVID-19. Chest imaging is used for cross validation. Chest CT is highly recommended as the preferred imaging diagnosis method for COVID-19 due to its high density and high spatial resolution. The common CT manifestation of COVID-19 includes multiple segmental ground glass opacities (GGOs) distributed dominantly in extrapulmonary/subpleural zones and along bronchovascular bundles with crazy paving sign and interlobular septal thickening and consolidation. Pleural effusion or mediastinal lymphadenopathy is rarely seen. In CT imaging, COVID-19 manifests differently in its various stages including the early stage, the progression (consolidation) stage, and the absorption stage. In its early stage, it manifests as scattered flaky GGOs in various sizes, dominated by peripheral pulmonary zone/subpleural distributions. In the progression state, GGOs increase in number and/or size, and lung consolidations may become visible. The main manifestation in the absorption stage is interstitial change of both lungs, such as fibrous cords and reticular opacities. Differentiation between COVID-19 pneumonia and other viral pneumonias are also analyzed. Thus, CT examination can help reduce false negatives of nucleic acid tests.

The novel coronavirus 2019-nCoV: Its evolution and transmission into humans causing global COVID-19 pandemic

A novel coronavirus strain 2019-nCoV has caused a rapid global pandemic-COVID-19. Scientists have taken onto the task of characterizing this new virus and understanding how this virus has transmitted to humans. All preliminary studies have found some striking similarities between this new virus and the SARS-CoV that caused a similar kind of epidemic in 2002-2003. Through bioinformatics tools, a great deal of information has been gathered about the origin, evolution and zoonosis of this virus. We, in this review, report the symptoms, mode of transmission and available and putative treatments to tackle 2019-nCoV infections. We also comprehensively summarize all the information so far made available regarding the genome, evolution and zoonosis of this virus.

Recent Progress in the Drug Development Targeting SARS-CoV-2 Main Protease as Treatment for COVID-19

The sudden outbreak of 2019 novel coronavirus (2019-nCoV, later named SARS-CoV-2) rapidly turned into an unprecedented pandemic of coronavirus disease 2019 (COVID-19). This global healthcare emergency marked the third occurrence of a deadly coronavirus (CoV) into the human society after entering the new millennium, which overwhelmed the worldwide healthcare system and affected the global economy. However, therapeutic options for COVID-19 are still very limited. Developing drugs targeting vital proteins in viral life cycle is a feasible approach to overcome this dilemma. Main protease (M^pro) plays a dominant role in processing CoV-encoded polyproteins which mediate the assembly of replication-transcription machinery and is thus recognized as an ideal antiviral target. Here we summarize the recent progress in the discovery of anti-SARS-CoV-2 agents against M^pro. Combining structural study, virtual screen, and experimental screen, numerous therapeutic candidates including repurposed drugs and ab initio designed compounds have been proposed. Such collaborative effort from the scientific community would accelerate the pace of developing efficacious treatment for COVID-19.

Clinical Characteristics of 5 COVID-19 Cases With Non-respiratory Symptoms as the First Manifestation in Children

An outbreak of the novel coronavirus disease 2019 (COVID-19) occurred in Wuhan, China, in December 2019, which then rapidly spread to more than 80 countries. However, detailed information on the characteristics of COVID-19 in children is still scarce. Five patients with non-respiratory symptoms as the first manifestation were hospitalized from the emergency department, and were later confirmed to have COVID-19, between 23 January and 20 February 2020, at the Wuhan Children's Hospital. SARS-CoV-2 nucleic acid detection was positive for all the patients. Four of the patients were male and one was female, and their ages ranged from 2-months to 5.6 years. All lived in Wuhan. One patient had a clear history of exposure to SARS-CoV-2, one had a suspected history of exposure, while the others had no exposure history. For three of the five patients, the primary onset disease required an emergency operation or treatment, and included intussusception, acute suppurative appendicitis perforation with local peritonitis, and traumatic subdural hemorrhage with convulsion, while for the other two it was acute gastroenteritis (including one patient with hydronephrosis and a stone in his left kidney). During the course of the disease, four of the five patients had a fever, whereas one case had no fever or cough. Two patients had leukopenia, and one also had lymphopenia. In the two cases of severe COVID-19, the levels of CRP, PCT, serum ferritin, IL-6, and IL-10 were significantly increased, whereas the numbers of CD3+, CD4+, CD8+ T lymphocytes, and CD16 + CD56 natural killer cells were decreased. We also found impaired liver, kidney, and myocardial functions; the presence of hypoproteinemia, hyponatremia, and hypocalcemia; and, in one case, abnormal coagulation function. Except for one patient who had a rotavirus infection, all patients tested negative for common pathogens, including the influenza virus, parainfluenza virus, respiratory syncytial virus, adenovirus, enterovirus, mycoplasma, Chlamydia, and Legionella. Chest CT images of all the patients showed patches or ground-glass opacities in the lung periphery or near the pleura, even large consolidations. This case series is the first report to describe the clinical features of COVID-19 with non-respiratory symptoms as the first manifestation in children.

Hot Topic Commentary on COVID-19

The recent pandemic outbreak of COVID-19 (severe acute respiratory syndrome coronavirus 2; SARS-CoV-2) worldwide caught the health care systems in every country around the world by storm and without a proper defense mechanism to cope and control such a pandemic. In this special Theme issue, we would like to discuss the latest treatment modalities available around the world in tackling this dreadful disease.

Are the cutaneous manifestations during or due to SARS-CoV-2 infection/COVID-19 frequent or not? Revision of possible pathophysiologic mechanisms

BACKGROUND

SARS-Cov-2 is a single-stranded RNA virus, a Betacoronavirus, composed of 16 non-structural proteins, with specific roles in replication of coronaviruses. The pathogenesis of COVID-19 is not yet fully understood. The virus and host factors interplay among distinct outcomes of infected patients.

METHODS

Using MeSH (Medical Subject Headings) in PubMed, authors searched for articles cotaining information on COVID-19 and the skin.

RESULTS

The pathophysiology of the disease is multifactorial: association with innate immune response, hypercoagulability state, lung tissue damage, neurological and/or gastrointestinal tract involvement, monocytic/macrophage activation syndrome, culminating in exaggerated cytokine secretion, called "cytokine storm", which leads to worsening and death. These systemic conditions may be associated with cutaneous lesions, that have polymorphic aspects, where at histopathological level show involvement in different skin changes. These lesions may be associated with multisystemic manifestations that could occur due to angiotensin-converting enzyme 2 receptor and transmembrane serine protease action, allowing the pulmonary infection and possibly skin manifestation. Several reports in literature show cutaneous lesions similar to chilblain, urticarial eruptions, diffuse or disseminated erythema, livedo racemosa, blue toe syndrome, retiform purpura, vesicle trunk, purpuric exanthema or exanthema with clinical aspects of symmetrical drug-related intertriginous and flexural exanthema (SDRIFE) and others.

CONCLUSIONS

This review describes the complexity of Covid-19, pathophysiological and clinical aspects, dermatological finding and other dermatological conditions associated with SARS-CoV-2 infection or COVID-19.

Coronaviruses: a paradigm of new emerging zoonotic diseases

A novel type of coronavirus (2019-nCoV) infecting humans appeared in Wuhan, China, at the end of December 2019. Since the identification of the outbreak the infection quickly spread involving in one month more than 31,000 confirmed cases with 638 death. Molecular analysis suggest that 2019-nCoV could be originated from bats after passaging in intermediate hosts, highlighting the high zoonotic potential of coronaviruses.