Human intestinal tract serves as an alternative infection route for Middle East respiratory syndrome coronavirus

Potential Diagnostic Systems for Coronavirus Detection: a Critical Review

Abstract

Currently there are no effective anti-viral drugs for SARS-CoV-2, so the primary line of defense is to detect infected cases as soon as possible. The high rate of contagion for this virus and the highly nonspecific symptoms of the disease (Coronovirus disease 2019, (Covid-19)) that it causes, such as respiratory symptoms, cough, dyspnea, fever, and viral pneumonia, require the urgent establishment of precise and fast diagnostic tests to verify suspected cases, screen patients, and conduct virus surveillance. Nowadays, several virus detection methods are available for viral diseases, which act on specific properties of each virus or virus family, therefore, further investigations and trials are needed to find a highly efficient and accurate detection method to detect and prevent the outcomes of the disease. Hence, there is an urgent need for more and precise studies in this field. In this review, we discussed the properties of a new generation of coronaviruses (SARS-CoV-2) following routine virus detection methods and proposed new strategies and the use of potential samples for SARS-CoV-2 detection.

Graphical Abstract

Engineering a Model to Study Viral Infections: Bioprinting, Microfluidics, and Organoids to Defeat Coronavirus Disease 2019 (COVID-19)

While the number of studies related to severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) is constantly growing, it is essential to provide a framework of modeling viral infections. Therefore, this review aims to describe the background presented by earlier used models for viral studies and an approach to design an "ideal" tissue model for SARS-CoV-2 infection. Due to the previous successful achievements in antiviral research and tissue engineering, combining the emerging techniques such as bioprinting, microfluidics, and organoid formation are considered to be one of the best approaches to form in vitro tissue models. The fabrication of an integrated multi-tissue bioprinted platform tailored for SARS-CoV-2 infection can be a great breakthrough that can help defeat coronavirus disease in 2019.

A high throughput screen for TMPRSS2 expression identifies FDA-approved and clinically advanced compounds that can limit SARS-CoV-2 entry

SARS-CoV-2 (2019-nCoV) is the pathogenic coronavirus responsible for the global pandemic of COVID-19 disease. The Spike (S) protein of SARS-CoV-2 attaches to host lung epithelial cells through the cell surface receptor ACE2, a process dependent on host proteases including TMPRSS2. Here, we identified small molecules that can reduce surface expression of TMPRSS2 using a 2,700 FDA-approved or current clinical trial compounds. Among these, homoharringtonine and halofuginone appear the most potent agents, reducing endogenous TMPRSS2 expression at sub-micromolar concentrations. These effects appear to be mediated by a drug-induced alteration in TMPRSS2 protein stability. We further demonstrate that halofuginone modulates TMPRSS2 levels through proteasomal-mediated degradation that involves the E3 ubiquitin ligase component DDB1- and CUL4-associated factor 1 (DCAF1). Finally, cells exposed to homoharringtonine and halofuginone, at concentrations of drug known to be achievable in human plasma, demonstrated marked resistance to SARS-CoV-2 pseudoviral infection. Given the safety and pharmacokinetic data already available for the compounds identified in our screen, these results should help expedite the rational design of human clinical trials designed to combat COVID-19 infection.

Newly Emerging Human Coronaviruses: Animal Models and Vaccine Research for SARS, MERS, and COVID-19

The recent emergence of the novel coronavirus (CoV) or severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) poses a global threat to human health and economy. As of June 26, 2020, over 9.4 million cases of infection, including 482,730 deaths, had been confirmed across 216 countries. To combat a devastating virus pandemic, numerous studies on vaccine development are urgently being accelerated. In this review article, we take a brief look at the characteristics of SARS-CoV-2 in comparison to SARS and Middle East respiratory syndrome (MERS)-CoVs and discuss recent approaches to coronavirus disease-2019 (COVID-19) vaccine development.

Viruses harness YxxØ motif to interact with host AP2M1 for replication: A vulnerable broad-spectrum antiviral target

Targeting a universal host protein exploited by most viruses would be a game-changing strategy that offers broad-spectrum solution and rapid pandemic control including the current COVID-19. Here, we found a common YxxØ-motif of multiple viruses that exploits host AP2M1 for intracellular trafficking. A library chemical, N-(p-amylcinnamoyl)anthranilic acid (ACA), was identified to interrupt AP2M1-virus interaction and exhibit potent antiviral efficacy against a number of viruses in vitro and in vivo, including the influenza A viruses (IAVs), Zika virus (ZIKV), human immunodeficiency virus, and coronaviruses including MERS-CoV and SARS-CoV-2. YxxØ mutation, AP2M1 depletion, or disruption by ACA causes incorrect localization of viral proteins, which is exemplified by the failure of nuclear import of IAV nucleoprotein and diminished endoplasmic reticulum localization of ZIKV-NS3 and enterovirus-A71-2C proteins, thereby suppressing viral replication. Our study reveals an evolutionarily conserved mechanism of protein-protein interaction between host and virus that can serve as a broad-spectrum antiviral target.

Psychiatric face of COVID-19

The Coronavirus Disease 2019 (COVID-19) represents a severe multiorgan pathology which, besides cardio-respiratory manifestations, affects the function of the central nervous system (CNS). The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), similarly to other coronaviruses demonstrate neurotropism; the viral infection of the brain stem may complicate the course of the disease through damaging central cardio-respiratory control. The systemic inflammation as well as neuroinflammatory changes are associated with massive increase of the brain pro-inflammatory molecules, neuroglial reactivity, altered neurochemical landscape and pathological remodelling of neuronal networks. These organic changes, emerging in concert with environmental stress caused by experiences of intensive therapy wards, pandemic fears and social restrictions, promote neuropsychiatric pathologies including major depressive disorder, bipolar disorder (BD), various psychoses, obsessive-compulsive disorder and post-traumatic stress disorder. The neuropsychiatric sequelae of COVID-19 represent serious clinical challenge that has to be considered for future complex therapies.

Differential immune activation profile of SARS-CoV-2 and SARS-CoV infection in human lung and intestinal cells: Implications for treatment with IFN-β and IFN inducer

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SARS-CoV-2 infection was more robust than SARS-CoV in Calu3. In contrast, SARS-CoV infected intestinal epithelial cells more efficiently.

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SARS-CoV-2 infection launched an attenuated interferon and pro-inflammatory cytokines/chemokines response in both Calu3 and Caco2 cells, despite robust virus infection and propagation.

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SARS-CoV-2 was more sensitive to IFNβ and poly(I:C) pretreatment than that of SARS-CoV.

Objectives

Respiratory and intestinal tract are two primary target organs of SARS-CoV-2 infection. However, detailed characterization of the host-virus interplay in infected human lung and intestinal epithelial cells is lacking.

Methods

We utilized immunofluorescence assays, flow cytometry, and RT-qPCR to delineate the virological features and the innate immune response of the host cells against SARS-CoV-2 infection in two prototype human cell lines representing the human lung (Calu3) and intestinal (Caco2) epithelium when compared with SARS-CoV.

Results

Lung epithelial cells were significantly more susceptible to SARS-CoV-2 compared to SARS-CoV. However, SARS-CoV-2 infection induced an attenuated pro-inflammatory cytokines/chemokines induction and type I and type II IFN responses. A single dose of 10 U/mL interferon-β (IFNβ) pretreatment potently protected both Calu3 and Caco2 against SARS-CoV-2 infection. Interestingly, SARS-CoV-2 was more sensitive to the pretreatment with IFNβ and IFN inducer than SARS-CoV in Calu3.

Conclusions

Despite robust infection in both human lung and intestinal epithelial cells, SARS-CoV-2 could attenuate the virus-induced pro-inflammatory response and IFN response. Pre-activation of the type I IFN signaling pathway primed a highly efficient antiviral response in the host against SARS-CoV-2 infection, which could serve as a potential therapeutic and prophylactic maneuver to COVID-19 patients.

COVID-19 and the Gut Microbiome: More than a Gut Feeling

Due to its fundamental role in the induction, training, and function of the immune system, it is critical to include characterizations of the gut microbiome in clinical trials and studies that aim to broaden our understanding of coronavirus disease 2019 (COVID-19). Understanding the “gut-lung axes,” where gut microbiome composition influences the lung’s susceptibility to viral infections and viral infections of the lung alter gut microbiome composition toward proinflammatory functional dysbiosis, will be critical in addressing COVID-19, including disease progression, the importance of preexisting conditions, and the risk for developing complications.

Due to its fundamental role in the induction, training, and function of the immune system, it is critical to include characterizations of the gut microbiome in clinical trials and studies that aim to broaden our understanding of coronavirus disease 2019 (COVID-19). Understanding the “gut-lung axes,” where gut microbiome composition influences the lung’s susceptibility to viral infections and viral infections of the lung alter gut microbiome composition toward proinflammatory functional dysbiosis, will be critical in addressing COVID-19, including disease progression, the importance of preexisting conditions, and the risk for developing complications. These insights may further help to develop better intervention strategies for COVID-19 and other diseases caused by respiratory viruses.

Making Waves: Coronavirus detection, presence and persistence in the water environment: State of the art and knowledge needs for public health

The main route of transmission of the human coronaviruses (HCoVs), and presumably also of the new pandemic SARS-CoV-2, is via droplets and close contacts, however their fecal elimination also suggests the possible spread via water. A scientific literature search was thus carried out to highlight the current state of the art and knowledge gaps regarding coronavirus in water. Since 1978 only 22 studies have met the inclusion criteria, and considered heterogeneous purposes, detection methods and types of water. In vitro experiments have addressed the recovery efficiency of analytical methods, survival in different types of water and the removal efficiency of water treatments. Field studies have monitored coronaviruses in surface waters, sewage, slurry, and biosolids. Overall, at the lab scale, HCoVs or surrogates can survive for several days at 4 °C, however their persistence is lower compared with non-enveloped viruses and is strongly influenced by temperature and organic or microbial pollution. HCoVs have rarely been detected in field investigations, however may be due to the low recovery efficiency of the analytical methods. The scarcity of information on HCoV in the environment suggests that research is needed to understand the fate of these viruses in the water cycle.

Clinical and Epidemiological Features of a Family Cluster of Symptomatic and Asymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Infection

In a family experiencing coronavirus disease 2019, the parents and 2 children aged 2 and 5 years became infected but the youngest child was not infected. Both children initially shed infectious virus, but cleared the virus after 5 to 6 days in the nasopharynx. However, viral RNA was continuously detected in the children's stool for more than 4 weeks.

Critical Role of Type III Interferon in Controlling SARS-CoV-2 Infection in Human Intestinal Epithelial Cells

Severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) is an unprecedented worldwide health problem that requires concerted and global approaches to stop the coronavirus 2019 (COVID-19) pandemic. Although SARS-CoV-2 primarily targets lung epithelium cells, there is growing evidence that the intestinal epithelium is also infected. Here, using both colon-derived cell lines and primary non-transformed colon organoids, we engage in the first comprehensive analysis of the SARS-CoV-2 life cycle in human intestinal epithelial cells (hIECs). Our results demonstrate that hIECs fully support SARS-CoV-2 infection, replication, and production of infectious de novo virus particles. We found that viral infection elicits an extremely robust intrinsic immune response where interferon-mediated responses are efficient at controlling SARS-CoV-2 replication and de novo virus production. Taken together, our data demonstrate that hIECs are a productive site of SARS-CoV-2 replication and suggest that the enteric phase of SARS-CoV-2 may participate in the pathologies observed in COVID-19 patients by contributing to increasing patient viremia and fueling an exacerbated cytokine response.

Use of SARS-CoV-2-infected deceased organ donors: Should we always "just say no?"

In the context of a rapidly evolving pandemic, multiple organizations have released guidelines stating that all organs from potential deceased donors with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection should be deferred, including from otherwise medically eligible donors found to have mild or asymptomatic SARS-CoV-2 discovered on routine donor screening. In this article, we critically examine the available data on the risk of transmission of SARS-CoV-2 through organ transplantation. The isolation of SARS-CoV-2 from nonlung clinical specimens, the detection of SARS-CoV-2 in autopsy specimens, previous experience with the related coronaviruses SARS-CoV and MERS-CoV, and the vast experience with other common RNA respiratory viruses are all addressed. Taken together, these data provide little evidence to suggest the presence of intact transmissible SARS-CoV in organs that can potentially be transplanted, specifically liver and heart. Other considerations including ethical, financial, societal, and logistical concerns are also addressed. We conclude that, for selected patients with high waitlist mortality, transplant programs should consider accepting heart or liver transplants from deceased donors with SARS-CoV-2 infection.

Gastrointestinal involvement in COVID-19: a systematic review and meta-analysis

BACKGROUND

Patients with COVID-19 usually manifest fever and respiratory symptoms. However, some patients also experience gastrointestinal (GI) symptoms such as diarrhea, vomiting and abdominal pain. In addition, SARS-CoV-2 RNA has been detected in feces of infected patients. Currently there is huge evolving research interest in this potentially lethal disease. We systematically reviewed and meta-analyzed the evidence suggesting involvement of the digestive system in COVID-19.

METHODS

PubMed, Medline and Embase databases were searched up to 10 April 2020, using suitable keywords. Individual and pooled prevalence rates with 95% confidence intervals (CI) were calculated using the fixed- or random-effects model as appropriate. Heterogeneity between studies was calculated employing the Cochran Q test and I2 values, whereas the possibility of publication bias was examined by constructing funnel plots. Additionally, subgroup and sensitivity analyses were performed.

RESULTS

In adult COVID-19 patients, the prevalence rates (95%CI) for all GI symptoms, and separately for diarrhea, nausea/vomiting, and abdominal discomfort/pain were 9.8% (6.4-14.7), 10.4% (95%CI 7.7-13.9), 7.7% (95%CI 4.8-12.1), and 6.9% (95%CI 3.9-11.9) respectively. The prevalence rates for children were 9.6% (95%CI 6.3-14.3) for all symptoms, 9.6% (95%CI 6.3-14.3) for diarrhea, and 6.8% (95% CI 4.2-11) for nausea/vomiting. In 30.3% (95%CI 10.5-61.6) of the patients SARS-CoV-2 RNA was detected in feces.

CONCLUSIONS

A percentage of patients with COVID-19 will manifest symptoms from the digestive system. The GI tract may be a target organ and potential transmission route of SARS-CoV-2, with important implications for disease management and transmission.

The Role of Human Coronavirus Infection in Pediatric Acute Gastroenteritis

Since human coronavirus (HCoV)-like particles were detected in the stool specimens of acute gastroenteritis and necrotizing enterocolitis children with electron microscopy, the relationship between HCoV and the pediatric gastrointestinal illness had been recognized. In recent years, the overall detection rates have been low and have varied by region. HCoVs have not been considered as the major pathogens in pediatric acute gastroenteritis. HCoVs detected in children with acute gastroenteritis have included 229E, OC43, HKU1, NL63, and severe acute respiratory syndrome coronavirus, Middle East Respiratory Syndrome Coronavirus and severe acute respiratory syndrome coronavirus-2 have also been associated with gastrointestinal symptoms in children. Although digestive tract has been recognized as an infection route, it has not been possible to fully investigate the association between HCoVs infection and the gastrointestinal symptoms because of the limited number of pediatric cases. Furthermore, pathologic features have not been clear. Till now, our knowledge of severe acute respiratory syndrome coronavirus-2 is limited. However, diarrhea and vomiting have been seen in pediatric cases, particularly in newborns and infants. It has been necessary to pay more attention on gastrointestinal transmission to identify the infected children early and avoid the children without apparent or mild symptoms becoming the sources of infection.

Gastrointestinal Manifestations of SARS-CoV-2 Infection and Virus Load in Fecal Samples From a Hong Kong Cohort: Systematic Review and Meta-analysis

BACKGROUND & AIMS

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which has been characterized by fever, respiratory, and gastrointestinal symptoms as well as shedding of virus RNA into feces. We performed a systematic review and meta-analysis of published gastrointestinal symptoms and detection of virus in stool and also summarized data from a cohort of patients with COVID-19 in Hong Kong.

METHODS

We collected data from the cohort of patients with COVID-19 in Hong Kong (N = 59; diagnosis from February 2 through February 29, 2020),and searched PubMed, Embase, Cochrane, and 3 Chinese databases through March 11, 2020, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We analyzed pooled data on the prevalence of overall and individual gastrointestinal symptoms (loss of appetite, nausea, vomiting, diarrhea, and abdominal pain or discomfort) using a random effects model.

RESULTS

Among the 59 patients with COVID-19 in Hong Kong, 15 patients (25.4%) had gastrointestinal symptoms, and 9 patients (15.3%) had stool that tested positive for virus RNA. Stool viral RNA was detected in 38.5% and 8.7% among those with and without diarrhea, respectively (P = .02). The median fecal viral load was 5.1 log10 copies per milliliter in patients with diarrhea vs 3.9 log10 copies per milliliter in patients without diarrhea (P = .06). In a meta-analysis of 60 studies comprising 4243 patients, the pooled prevalence of all gastrointestinal symptoms was 17.6% (95% confidence interval [CI], 12.3-24.5); 11.8% of patients with nonsevere COVID-19 had gastrointestinal symptoms (95% CI, 4.1-29.1), and 17.1% of patients with severe COVID-19 had gastrointestinal symptoms (95% CI, 6.9-36.7). In the meta-analysis, the pooled prevalence of stool samples that were positive for virus RNA was 48.1% (95% CI, 38.3-57.9); of these samples, 70.3% of those collected after loss of virus from respiratory specimens tested positive for the virus (95% CI, 49.6-85.1).

CONCLUSIONS

In an analysis of data from the Hong Kong cohort of patients with COVID-19 and a meta-analysis of findings from publications, we found that 17.6% of patients with COVID-19 had gastrointestinal symptoms. Virus RNA was detected in stool samples from 48.1% patients, even in stool collected after respiratory samples had negative test results. Health care workers should therefore exercise caution in collecting fecal samples or performing endoscopic procedures in patients with COVID-19, even during patient recovery.

2019 novel coronavirus disease (COVID-19) in patients with inflammatory bowel diseases

BACKGROUND

Data on patients with inflammatory bowel diseases (IBD) who have had 2019 novel coronavirus (SARS-CoV-2) disease (COVID-19) are needed.

AIMS

To report the clinical characteristics, including gastrointestinal symptoms, of COVID-19 in IBD patients, and to assess the risk of COVID-19 in IBD.

METHODS

This case series included consecutive IBD patients with laboratory-confirmed COVID-19. Age-adjusted cumulative incidences were compared with the general population in the Madrid region.

RESULTS

Through April 8, 12 of 1918 IBD patients were diagnosed with COVID-19. The average age was 52 years, 75% of the patients were female and 58.3% had Crohn's disease. Seven patients (58%) were on maintenance treatment with immunomodulators/biologics, of these four with combined therapy (33%). Eight patients (66%) required hospitalisation (one intensive care unit admission, and two deaths), and four patients were isolated at home. Nine patients had diarrhoea ranging between 4 and 10 loose stools per day (mean 5.4, SD 1.6). In five patients (42%) diarrhoea was a presenting symptom. In two patients, diarrhoea was the only symptom at debut. Cumulative incidence of COVID-19 was 6.2 per 1000 IBD patients. IBD patients had a lower adjusted incidence ratio of COVID-19 (OR 0.74, 95% CI 0.70-0.77; P < 0.001), and a similar associated mortality ratio (OR 0.95, 95% CI: 0.84-1.06; P = 0.36), compared with the general population.

CONCLUSIONS

IBD patients do not have an increased risk of COVID-19 and associated mortality compared with the general population. In many IBD patients, diarrhoea was a presenting symptom, and sometimes, was the only symptom at onset of COVID-19.

A brief history of organoids

In vitro cell cultures are crucial research tools for modeling human development and diseases. Although the conventional monolayer cell cultures have been widely used in the past, the lack of tissue architecture and complexity of such model fails to inform the true biological processes in vivo. Recent advances in the organoid technology have revolutionized the in vitro culture tools for biomedical research by creating powerful three-dimensional (3D) models to recapitulate the cellular heterogeneity, structure, and functions of the primary tissues. Such organoid technology enables researchers to recreate human organs and diseases in a dish and thus holds great promises for many translational applications such as regenerative medicine, drug discovery, and precision medicine. In this review, we provide an overview of the organoid history and development. We discuss the strengths and limitations of organoids as well as their potential applications in the laboratory and the clinic.

COVID-19 and the Digestive System

The outbreak of novel coronavirus pneumonia in 2019 (Coronavirus disease 2019 [COVID-19]) is now threatening global public health. Although COVID-19 is principally defined by its respiratory symptoms, it is now clear that the virus can also affect the digestive system. In this review, we elaborate on the close relationship between COVID-19 and the digestive system, focusing on both the clinical findings and potential underlying mechanisms of COVID-19 gastrointestinal pathogenesis.

Utilization of deceased donors during a pandemic: argument against using SARS-CoV-2-positive donors

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly become an unprecedented pandemic that has impacted society, disrupted hospital functions, strained health care resources, and impacted the lives of transplant professionals. Despite this, organ failure and the need for transplant continues throughout the United States. Considering the perpetual scarcity of deceased donor organs, Kates et al present a viewpoint that advocates for the utilization of coronavirus disease 2019 (COVID-19)-positive donors in selected cases. We present a review of the current literature that details the potential negative consequences of COVID-19-positive donors. The factors we consider include (1) the risk of blood transmission of SARS-CoV-2, (2) involvement of donor organs, (3) lack of effective therapies, (4) exposure of health care and recovery teams, (5) disease transmission and propagation, and (6) hospital resource utilization. While we acknowledge that transplant fulfills the mission of saving lives, it is imperative to consider the consequences not only to our recipients but also to the community and to health care workers, particularly in the absence of effective preventative or curative therapies. For these reasons, we believe the evidence and risks show that COVID-19 infection should continue to remain a contraindication for donation, as has been the initial response of donation and transplant societies.

A Comprehensive Review of Manifestations of Novel Coronaviruses in the Context of Deadly COVID-19 Global Pandemic

Since December 2019, the global pandemic caused by the highly infectious novel coronavirus 2019-nCoV (COVID-19) has been rapidly spreading. As of April 2020, the outbreak has spread to over 210 countries, with over 2,400,000 confirmed cases and over 170,000 deaths.1 COVID-19 causes a severe pneumonia characterized by fever, cough and shortness of breath. Similar coronavirus outbreaks have occurred in the past causing severe pneumonia like COVID-19, most recently, severe acute respiratory syndrome coronavirus (SARS-CoV) and middle east respiratory syndrome coronavirus (MERS-CoV). However, over time, SARS-CoV and MERS-CoV were shown to cause extrapulmonary signs and symptoms including hepatitis, acute renal failure, encephalitis, myositis and gastroenteritis. Similarly, sporadic reports of COVID-19 related extrapulmonary manifestations emerge. Unfortunately, there is no comprehensive summary of the multiorgan manifestations of COVID-19, making it difficult for clinicians to quickly educate themselves about this highly contagious and deadly pathogen. What is more, is that SARS-CoV and MERS-CoV are the closest humanity has come to combating something similar to COVID-19, however, there exists no comparison between the manifestations of any of these novel coronaviruses. In this review, we summarize the current knowledge of the manifestations of the novel coronaviruses SARS-CoV, MERS-CoV and COVID-19, with a particular focus on the latter, and highlight their differences and similarities.

Is SARS-CoV-2 Also an Enteric Pathogen With Potential Fecal-Oral Transmission? A COVID-19 Virological and Clinical Review

In as few as 3 months, coronavirus disease 2019 (COVID-19) has spread and ravaged the world at an unprecedented speed in modern history, rivaling the 1918 flu pandemic. Severe acute respiratory syndrome coronavirus-2, the culprit virus, is highly contagious and stable in the environment and transmits predominantly among humans via the respiratory route. Accumulating evidence suggest that this virus, like many of its related viruses, may also be an enteric virus that can spread via the fecal-oral route. Such a hypothesis would also contribute to the rapidity and proliferation of this pandemic. Here we briefly summarize what is known about this family of viruses and literature basis of the hypothesis that severe acute respiratory syndrome coronavirus-2 is capable of infecting the gastrointestinal tract and shedding in the environment for potential human-to-human transmission.

Clinical Insights into the Gastrointestinal Manifestations of COVID-19

The month of December 2019 became a critical part of the time of humanity when the first case of coronavirus disease 2019 (COVID-19) was reported in the Wuhan, Hubei Province in China. As of April 13th, 2020, there have been approximately 1.9 million cases and 199,000 deaths across the world, which were associated with COVID-19. The COVID-19 is the seventh coronavirus to be identified to infect humans. In the past, Severe Acute Respiratory Syndrome and Middle East Respiratory Syndrome were the two coronaviruses that infected humans with a high fatality, particularly among the elderly. Fatalities due to COVID-19 are higher in patients older than 50 years of age or those with multimorbid conditions. The COVID-19 is mainly transmitted through respiratory droplets, with the most common symptoms being high fever, cough, myalgia, atypical symptoms included sputum production, headache, hemoptysis and diarrhea. However, the incubation period can range from 2 to 14 days without any symptoms. It is particularly true with gastrointestinal (GI) symptoms in which patients can still shed the virus even after pulmonary symptoms have resolved. Given the high percentage of COVID-19 patients that present with GI symptoms (e.g., nausea and diarrhea), screening patients for GI symptoms remain essential. Recently, cases of fecal-oral transmission of COVID-19 have been confirmed in the USA and China, indicating that the virus can replicate in both the respiratory and digestive tract. Moreover, the epidemiology, clinical characteristics, diagnostic procedures, treatments and prevention of the gastrointestinal manifestations of COVID-19 remain to be elucidated.

Neuromechanisms of SARS-CoV-2: A Review

Recent studies have suggested the neuroinvasive potential of severe acute respiratory coronavirus 2 (SARS-CoV-2). Notably, neuroinvasiveness might be involved in the pathophysiology of coronavirus disease 2019 (COVID-19). Some studies have demonstrated that synapse-connected routes may enable coronaviruses to access the central nervous system (CNS). However, evidence related to the presence of SARS-CoV-2 in the CNS, its direct impact on the CNS, and the contribution to symptoms suffered, remain sparse. Here, we review the current literature that indicates that SARS-CoV-2 can invade the nervous system. We also describe the neural circuits that are potentially affected by the virus and their possible role in the progress of COVID-19. In addition, we propose several strategies to understand, diagnose, and treat the neurological symptoms of COVID-19.

Epidemiological and Clinical Characteristics of Cases During the Early Phase of COVID-19 Pandemic: A Systematic Review and Meta-Analysis

Background: On 29th December 2019, a cluster of cases displaying the symptoms of a "pneumonia of unknown cause" was identified in Wuhan, Hubei province of China. This systematic review and meta-analysis aims to review the epidemiological and clinical characteristics of COVID-19 cases in the early phase of the COVID-19 pandemic. Methods: The search strategy involved peer-reviewed studies published between 1st January and 11th February 2020 in Pubmed, Google scholar and China Knowledge Resource Integrated database. Publications identified were screened for their title and abstracts according to the eligibility criteria, and further shortlisted by full-text screening. Three independent reviewers extracted data from these studies, and studies were assessed for potential risk of bias. Studies comprising non-overlapping patient populations, were included for qualitative and quantitative synthesis of results. Pooled prevalence with 95% confidence intervals were calculated for patient characteristics. Results: A total of 29 publications were selected after full-text review. This comprised of 18 case reports, three case series and eight cross-sectional studies on patients admitted from mid-December of 2019 to early February of 2020. A total of 533 adult patients with pooled median age of 56 (95% CI: 49-57) and a pooled prevalence of male of 60% (95% CI: 52-68%) were admitted to hospital at a pooled median of 7 days (95% CI: 7-7) post-onset of symptoms. The most common symptoms at admission were fever, cough and fatigue, with a pooled prevalence of 90% (95% CI: 81-97%), 58% (95% CI: 47-68%), and 50% (95% CI: 29-71%), respectively. Myalgia, shortness of breath, headache, diarrhea and sore throat were less common with pooled prevalence of 27% (95% CI: 20-36%), 25% (95% CI: 15-35%), 10% (95% CI: 7-13%), 8% (95% CI: 5-13%), and 7% (95% CI: 1-15%), respectively. ICU patients had a higher proportion of shortness of breath at presentation, as well as pre-existing hypertension, cardiovascular disease and COPD, compared to non-ICU patients in 2 studies (n = 179). Conclusion: This study highlights the key epidemiological and clinical features of COVID-19 cases during the early phase of the COVID-19 pandemic.

Overview of lethal human coronaviruses

Coronavirus infections of multiple origins have spread to date worldwide, causing severe respiratory diseases. Seven coronaviruses that infect humans have been identified: HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1, SARS-CoV, MERS-CoV, and SARS-CoV-2. Among them, SARS-CoV and MERS-CoV caused outbreaks in 2002 and 2012, respectively. SARS-CoV-2 (COVID-19) is the most recently discovered. It has created a severe worldwide outbreak beginning in late 2019, leading to date to over 4 million cases globally. Viruses are genetically simple, yet highly diverse. However, the recent outbreaks of SARS-CoV and MERS-CoV, and the ongoing outbreak of SARS-CoV-2, indicate that there remains a long way to go to identify and develop specific therapeutic treatments. Only after gaining a better understanding of their pathogenic mechanisms can we minimize viral pandemics. This paper mainly focuses on SARS-CoV, MERS-CoV, and SARS-CoV-2. Here, recent studies are summarized and reviewed, with a focus on virus-host interactions, vaccine-based and drug-targeted therapies, and the development of new approaches for clinical diagnosis and treatment.

Features of enteric disease from human coronaviruses: Implications for COVID-19

Coronaviruses have long been studied in both human and veterinary fields. Whereas the initial detection of endemic human respiratory coronaviruses was problematic, detection of these and newly discovered human coronaviruses has been greatly facilitated with major advances in the laboratory. Nevertheless, technological factors can affect the accuracy and timeliness of virus detection. Many human coronaviruses can be variably found in stool samples. All human coronaviruses have been variably associated with symptoms of gastroenteritis. Coronaviruses can occasionally be cultured from enteric specimens, but most detection is accomplished with genetic amplification technologies. Excretion of viral RNA in stool can extend for a prolonged period. Culture‐positive stool samples have been found to exceed a fourteen day period after onset of infection for some coronaviruses. Virus can also sometimes be cultured from patients' respiratory samples during the late incubation period. Relatively asymptomatic patients may excrete virus. Both viable and nonviable virus can be found in the immediate environment of the patient, the health care worker, and less often the public. These lessons from the past study of animal and human coronaviruses can be extended to presumptions for severe acute respiratory syndrome coronavirus 2. Already, the early reports from the coronavirus disease‐2019 pandemic are confirming some concerns. These data have the cumulative potential to cause us to rethink some current and common public health and infection control strategies.

coronaviruses are variably found in human enteric samples during the course of infection.

abdominal and intestinal illnesses are associated with coronavirus infections.

enteric excretion of live virus and viral RNA have been confirmed.

occasionally, live virus can be found in stool samples to exceed a fourteen day period after disease onset, and virus can also be cultured from these samples during the late incubation period or from asymptomatic individuals.

Prevalence of Gastrointestinal Symptoms and Fecal Viral Shedding in Patients With Coronavirus Disease 2019: A Systematic Review and Meta-analysis

Importance

Coronavirus disease 2019 (COVID-19) is a global pandemic and can involve the gastrointestinal (GI) tract, including symptoms like diarrhea and shedding of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in feces.

Objective

To provide a pooled estimate of GI symptoms, liver enzyme levels outside reference ranges, and fecal tests positive for SARS-CoV-2 among patients with COVID-19.

Data Sources

An electronic literature search was performed for published (using MEDLINE/PubMed and Embase) and preprint (using bioRxiv and medRxiv) studies of interest conducted from November 1, 2019, to March 30, 2020. Search terms included "COVID-19," "SARS-Cov-2," and/or "novel coronavirus."

Study Selection

Eligible studies were those including patients with SARS-CoV-2 infection who reported GI symptoms.

Data Extraction and Synthesis

Data on patients with GI symptoms (ie, diarrhea, nausea, or vomiting), liver enzyme level changes, and fecal shedding of virus were extracted. Quality of studies was examined using methodological index for nonrandomized studies. Pooled estimates (%) were reported with 95% CIs with level of heterogeneity (I2).

Main Outcomes and Measures

Study and patient characteristics with pooled detection rates for diarrhea, nausea or vomiting, liver enzyme levels outside reference ranges, and SARS-CoV-2 positivity in feces tests were analyzed.

Results

Of 1484 records reviewed, 23 published and 6 preprint studies were included in the analysis, with a total of 4805 patients (mean [SD] age, 52.2 [14.8] years; 1598 [33.2%] women) with COVID-19. The pooled rates were 7.4% (95% CI, 4.3%-12.2%) of patients reporting diarrhea and 4.6% (95% CI, 2.6%-8.0%) of patients reporting nausea or vomiting. The pooled rate for aspartate aminotransferase levels outside reference ranges was 20% (95% CI, 15.3%-25.6%) of patients, and the pooled rate for alanine aminotransferase levels outside reference ranges was 14.6% (95% CI, 12.8%-16.6%) of patients. Fecal tests that were positive for SARS-CoV-2 were reported in 8 studies, and viral RNA shedding was detected in feces in 40.5% (95% CI, 27.4%-55.1%) of patients. There was high level of heterogeneity (I2 = 94%), but no statistically significant publication bias noted.

Conclusions and Relevance

These findings suggest that that 12% of patients with COVID-19 will manifest GI symptoms; however, SAR-CoV-2 shedding was observed in 40.5% of patients with confirmed SARS-CoV-2 infection. This highlights the need to better understand what measures are needed to prevent further spread of this highly contagious pathogen.

COVID-19 patients' clinical characteristics, discharge rate, and fatality rate of meta-analysis

The aim of this study was to analyze the clinical data, discharge rate, and fatality rate of COVID-19 patients for clinical help. The clinical data of COVID-19 patients from December 2019 to February 2020 were retrieved from four databases. We statistically analyzed the clinical symptoms and laboratory results of COVID-19 patients and explained the discharge rate and fatality rate with a single-arm meta-analysis. The available data of 1994 patients in 10 literatures were included in our study. The main clinical symptoms of COVID-19 patients were fever (88.5%), cough (68.6%), myalgia or fatigue (35.8%), expectoration (28.2%), and dyspnea (21.9%). Minor symptoms include headache or dizziness (12.1%), diarrhea (4.8%), nausea and vomiting (3.9%). The results of the laboratory showed that the lymphocytopenia (64.5%), increase of C-reactive protein (44.3%), increase of lactic dehydrogenase (28.3%), and leukocytopenia (29.4%) were more common. The results of single-arm meta-analysis showed that the male took a larger percentage in the gender distribution of COVID-19 patients 60% (95% CI [0.54, 0.65]), the discharge rate of COVID-19 patients was 52% (95% CI [0.34,0.70]), and the fatality rate was 5% (95% CI [0.01,0.11]).

Coronavirus Infections and Type 2 Diabetes-Shared Pathways with Therapeutic Implications

Individuals with diabetes are at increased risk for bacterial, mycotic, parasitic, and viral infections. The severe acute respiratory syndrome (SARS)-CoV-2 (also referred to as COVID-19) coronavirus pandemic highlights the importance of understanding shared disease pathophysiology potentially informing therapeutic choices in individuals with type 2 diabetes (T2D). Two coronavirus receptor proteins, angiotensin-converting enzyme 2 (ACE2) and dipeptidyl peptidase-4 (DPP4) are also established transducers of metabolic signals and pathways regulating inflammation, renal and cardiovascular physiology, and glucose homeostasis. Moreover, glucose-lowering agents such as the DPP4 inhibitors, widely used in subjects with T2D, are known to modify the biological activities of multiple immunomodulatory substrates. Here, we review the basic and clinical science spanning the intersections of diabetes, coronavirus infections, ACE2, and DPP4 biology, highlighting clinical relevance and evolving areas of uncertainty underlying the pathophysiology and treatment of T2D in the context of coronavirus infection.

COVID-19, SARS and MERS: are they closely related?

BACKGROUND

The 2019 novel coronavirus (SARS-CoV-2) is a new human coronavirus which is spreading with epidemic features in China and other Asian countries; cases have also been reported worldwide. This novel coronavirus disease (COVID-19) is associated with a respiratory illness that may lead to severe pneumonia and acute respiratory distress syndrome (ARDS). Although related to the severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS), COVID-19 shows some peculiar pathogenetic, epidemiological and clinical features which to date are not completely understood.

AIMS

To provide a review of the differences in pathogenesis, epidemiology and clinical features of COVID-19, SARS and MERS.

SOURCES

The most recent literature in the English language regarding COVID-19 has been reviewed, and extracted data have been compared with the current scientific evidence about SARS and MERS epidemics.

CONTENT

COVID-19 seems not to be very different from SARS regarding its clinical features. However, it has a fatality rate of 2.3%, lower than that of SARS (9.5%) and much lower than that of MERS (34.4%). The possibility cannot be excluded that because of the less severe clinical picture of COVID-19 it can spread in the community more easily than MERS and SARS. The actual basic reproductive number (R0) of COVID-19 (2.0-2.5) is still controversial. It is probably slightly higher than the R0 of SARS (1.7-1.9) and higher than that of MERS (<1). A gastrointestinal route of transmission for SARS-CoV-2, which has been assumed for SARS-CoV and MERS-CoV, cannot be ruled out and needs further investigation.

IMPLICATIONS

There is still much more to know about COVID-19, especially as concerns mortality and its capacity to spread on a pandemic level. Nonetheless, all of the lessons we learned in the past from the SARS and MERS epidemics are the best cultural weapons with which to face this new global threat.

Bioengineering tools to speed up the discovery and preclinical testing of vaccines for SARS-CoV-2 and therapeutic agents for COVID-19

This review provides an update for the international research community on the cell modeling tools that could accelerate the understanding of SARS-CoV-2 infection mechanisms and could thus speed up the development of vaccines and therapeutic agents against COVID-19. Many bioengineering groups are actively developing frontier tools that are capable of providing realistic three-dimensional (3D) models for biological research, including cell culture scaffolds, microfluidic chambers for the culture of tissue equivalents and organoids, and implantable windows for intravital imaging. Here, we review the most innovative study models based on these bioengineering tools in the context of virology and vaccinology. To make it easier for scientists working on SARS-CoV-2 to identify and apply specific tools, we discuss how they could accelerate the discovery and preclinical development of antiviral drugs and vaccines, compared to conventional models.

Obstetric Management of COVID-19 in Pregnant Women

The 2019 novel coronavirus disease (COVID-19), which is caused by the novel beta coronavirus, SARS-CoV-2, is currently prevalent all over the world, causing thousands of deaths with relatively high virulence. Like two other notable beta coronaviruses, severe acute respiratory syndrome coronavirus-1 (SARS-CoV-1) and Middle East respiratory syndrome coronavirus (MERS-CoV), SARS-CoV-2 can lead to severe contagious respiratory disease. Due to impaired cellular immunity and physiological changes, pregnant women are susceptible to respiratory disease and are more likely to develop severe pneumonia. Given the prevalence of COVID-19, it is speculated that some pregnant women have already been infected. However, limited data are available for the clinical course and management of COVID-19 in pregnancy. Therefore, we conducted this review to identify strategies for the obstetric management of COVID-19. We compared the clinical course and outcomes of COVID-19, SARS, and MERS in pregnancy and discussed several drugs for the treatment of COVID-19 in pregnancy.

Positive RT-PCR in urine from an asymptomatic patient with novel coronavirus 2019 infection: a case report

Introduction: With the emergence of novel coronavirus disease 2019 (COVID-19) in many countries, medical resources currently focus on the treatment of confirmed patients and screening of suspected cases. Asymptomatic patients may be contagious, which makes epidemic control difficult. We describe an asymptomatic patient with a positive real-time polymerase chain reaction (RT-PCR) test in urine.Case report: An asymptomatic girl was identified during the epidemiological investigation of a confirmed COVID-19 patient. When admitted to the hospital on 24 February 2020, she had no clinical manifestations. A throat swab was negative for RT-PCR, but urine was positive. She was given antiviral and symptomatic supportive treatment. On 26 February, a throat swab RT-PCR was positive. RT-PCR in throat swabs and urine were negative on 3 and 5 March, and on 9 and 12 March, throat swabs were still negative. At follow-up on 26 March, she felt well, throat swab RT-PCR was negative, and isolation was lifted.Conclusion: The urine of asymptomatic patients may be contagious. RT-PCR in urine might be a useful supplement in screening when the RT-PCR is negative in throat swabs.

Infection of bat and human intestinal organoids by SARS-CoV-2

A novel coronavirus-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-emerged in humans in Wuhan, China, in December 2019 and has since disseminated globally^1,2. As of April 16, 2020, the confirmed case count of coronavirus disease 2019 (COVID-19) had surpassed 2 million. Based on full-genome sequence analysis, SARS-CoV-2 shows high homology to SARS-related coronaviruses identified in horseshoe bats^1,2. Here we show the establishment and characterization of expandable intestinal organoids derived from horseshoe bats of the Rhinolophus sinicus species that can recapitulate bat intestinal epithelium. These bat enteroids are fully susceptible to SARS-CoV-2 infection and sustain robust viral replication. Development of gastrointestinal symptoms in some patients with COVID-19 and detection of viral RNA in fecal specimens suggest that SARS-CoV-2 might cause enteric, in addition to respiratory, infection^3,4. Here we demonstrate active replication of SARS-CoV-2 in human intestinal organoids and isolation of infectious virus from the stool specimen of a patient with diarrheal COVID-19. Collectively, we established the first expandable organoid culture system of bat intestinal epithelium and present evidence that SARS-CoV-2 can infect bat intestinal cells. The robust SARS-CoV-2 replication in human intestinal organoids suggests that the human intestinal tract might be a transmission route of SARS-CoV-2.

Angiotensin-Converting Enzyme 2: SARS-CoV-2 Receptor and Regulator of the Renin-Angiotensin System: Celebrating the 20th Anniversary of the Discovery of ACE2

ACE2 (angiotensin-converting enzyme 2) has a multiplicity of physiological roles that revolve around its trivalent function: a negative regulator of the renin-angiotensin system, facilitator of amino acid transport, and the severe acute respiratory syndrome-coronavirus (SARS-CoV) and SARS-CoV-2 receptor. ACE2 is widely expressed, including, in the lungs, cardiovascular system, gut, kidneys, central nervous system, and adipose tissue. ACE2 has recently been identified as the SARS-CoV-2 receptor, the infective agent responsible for coronavirus disease 2019, providing a critical link between immunity, inflammation, ACE2, and cardiovascular disease. Although sharing a close evolutionary relationship with SARS-CoV, the receptor-binding domain of SARS-CoV-2 differs in several key amino acid residues, allowing for stronger binding affinity with the human ACE2 receptor, which may account for the greater pathogenicity of SARS-CoV-2. The loss of ACE2 function following binding by SARS-CoV-2 is driven by endocytosis and activation of proteolytic cleavage and processing. The ACE2 system is a critical protective pathway against heart failure with reduced and preserved ejection fraction including, myocardial infarction and hypertension, and against lung disease and diabetes mellitus. The control of gut dysbiosis and vascular permeability by ACE2 has emerged as an essential mechanism of pulmonary hypertension and diabetic cardiovascular complications. Recombinant ACE2, gene-delivery of Ace2, Ang 1-7 analogs, and Mas receptor agonists enhance ACE2 action and serve as potential therapies for disease conditions associated with an activated renin-angiotensin system. rhACE2 (recombinant human ACE2) has completed clinical trials and efficiently lowered or increased plasma angiotensin II and angiotensin 1-7 levels, respectively. Our review summarizes the progress over the past 20 years, highlighting the critical role of ACE2 as the novel SARS-CoV-2 receptor and as the negative regulator of the renin-angiotensin system, together with implications for the coronavirus disease 2019 pandemic and associated cardiovascular diseases.

CoVID-19: a Digestive Disease!

CoVID-19 is a Public Health Emergency of International Concern. Since the first case has been reported in Wuhan in China, evidence of associated severe acute respiratory syndrome is well established and the disease is accepted as a primarily respiratory infection. However, current available data are supporting a gastrointestinal tropism with great implications at multiple levels in the course of this disease. The gastrointestinal tract appears in the heart of the strategy for management of infected patients from diagnosis to post-recovery isolation policies. This review highlights the digestive aspects of CoVID-19. Keywords: ACE2, CoVID-19, Digestive, Endoscopy, Fecal transmission, Liver, Prognosis

Coronavirus Infections in Children Including COVID-19: An Overview of the Epidemiology, Clinical Features, Diagnosis, Treatment and Prevention Options in Children

Coronaviruses (CoVs) are a large family of enveloped, single-stranded, zoonotic RNA viruses. Four CoVs commonly circulate among humans: HCoV2-229E, -HKU1, -NL63 and -OC43. However, CoVs can rapidly mutate and recombine leading to novel CoVs that can spread from animals to humans. The novel CoVs severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in 2002 and Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012. The 2019 novel coronavirus (SARS-CoV-2) is currently causing a severe outbreak of disease (termed COVID-19) in China and multiple other countries, threatening to cause a global pandemic. In humans, CoVs mostly cause respiratory and gastrointestinal symptoms. Clinical manifestations range from a common cold to more severe disease such as bronchitis, pneumonia, severe acute respiratory distress syndrome, multi-organ failure and even death. SARS-CoV, MERS-CoV and SARS-CoV-2 seem to less commonly affect children and to cause fewer symptoms and less severe disease in this age group compared with adults, and are associated with much lower case-fatality rates. Preliminary evidence suggests children are just as likely as adults to become infected with SARS-CoV-2 but are less likely to be symptomatic or develop severe symptoms. However, the importance of children in transmitting the virus remains uncertain. Children more often have gastrointestinal symptoms compared with adults. Most children with SARS-CoV present with fever, but this is not the case for the other novel CoVs. Many children affected by MERS-CoV are asymptomatic. The majority of children infected by novel CoVs have a documented household contact, often showing symptoms before them. In contrast, adults more often have a nosocomial exposure. In this review, we summarize epidemiologic, clinical and diagnostic findings, as well as treatment and prevention options for common circulating and novel CoVs infections in humans with a focus on infections in children.

Virological assessment of hospitalized patients with COVID-2019

Coronavirus disease 2019 (COVID-19) is an acute infection of the respiratory tract that emerged in late 2019^1,2. Initial outbreaks in China involved 13.8% of cases with severe courses, and 6.1% of cases with critical courses³. This severe presentation may result from the virus using a virus receptor that is expressed predominantly in the lung^2,4; the same receptor tropism is thought to have determined the pathogenicity-but also aided in the control-of severe acute respiratory syndrome (SARS) in 2003⁵. However, there are reports of cases of COVID-19 in which the patient shows mild upper respiratory tract symptoms, which suggests the potential for pre- or oligosymptomatic transmission^6-8. There is an urgent need for information on virus replication, immunity and infectivity in specific sites of the body. Here we report a detailed virological analysis of nine cases of COVID-19 that provides proof of active virus replication in tissues of the upper respiratory tract. Pharyngeal virus shedding was very high during the first week of symptoms, with a peak at 7.11 × 10⁸ RNA copies per throat swab on day 4. Infectious virus was readily isolated from samples derived from the throat or lung, but not from stool samples-in spite of high concentrations of virus RNA. Blood and urine samples never yielded virus. Active replication in the throat was confirmed by the presence of viral replicative RNA intermediates in the throat samples. We consistently detected sequence-distinct virus populations in throat and lung samples from one patient, proving independent replication. The shedding of viral RNA from sputum outlasted the end of symptoms. Seroconversion occurred after 7 days in 50% of patients (and by day 14 in all patients), but was not followed by a rapid decline in viral load. COVID-19 can present as a mild illness of the upper respiratory tract. The confirmation of active virus replication in the upper respiratory tract has implications for the containment of COVID-19.

Virological assessment of hospitalized patients with COVID-2019

Coronavirus disease 2019 (COVID-19) is an acute infection of the respiratory tract that emerged in late 2019^1,2. Initial outbreaks in China involved 13.8% of cases with severe courses, and 6.1% of cases with critical courses³. This severe presentation may result from the virus using a virus receptor that is expressed predominantly in the lung^2,4; the same receptor tropism is thought to have determined the pathogenicity-but also aided in the control-of severe acute respiratory syndrome (SARS) in 2003⁵. However, there are reports of cases of COVID-19 in which the patient shows mild upper respiratory tract symptoms, which suggests the potential for pre- or oligosymptomatic transmission^6-8. There is an urgent need for information on virus replication, immunity and infectivity in specific sites of the body. Here we report a detailed virological analysis of nine cases of COVID-19 that provides proof of active virus replication in tissues of the upper respiratory tract. Pharyngeal virus shedding was very high during the first week of symptoms, with a peak at 7.11 × 10⁸ RNA copies per throat swab on day 4. Infectious virus was readily isolated from samples derived from the throat or lung, but not from stool samples-in spite of high concentrations of virus RNA. Blood and urine samples never yielded virus. Active replication in the throat was confirmed by the presence of viral replicative RNA intermediates in the throat samples. We consistently detected sequence-distinct virus populations in throat and lung samples from one patient, proving independent replication. The shedding of viral RNA from sputum outlasted the end of symptoms. Seroconversion occurred after 7 days in 50% of patients (and by day 14 in all patients), but was not followed by a rapid decline in viral load. COVID-19 can present as a mild illness of the upper respiratory tract. The confirmation of active virus replication in the upper respiratory tract has implications for the containment of COVID-19.

Coronavirus Infections in Children Including COVID-19: An Overview of the Epidemiology, Clinical Features, Diagnosis, Treatment and Prevention Options in Children

Coronaviruses (CoVs) are a large family of enveloped, single-stranded, zoonotic RNA viruses. Four CoVs commonly circulate among humans: HCoV2-229E, -HKU1, -NL63 and -OC43. However, CoVs can rapidly mutate and recombine leading to novel CoVs that can spread from animals to humans. The novel CoVs severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in 2002 and Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012. The 2019 novel coronavirus (SARS-CoV-2) is currently causing a severe outbreak of disease (termed COVID-19) in China and multiple other countries, threatening to cause a global pandemic. In humans, CoVs mostly cause respiratory and gastrointestinal symptoms. Clinical manifestations range from a common cold to more severe disease such as bronchitis, pneumonia, severe acute respiratory distress syndrome, multi-organ failure and even death. SARS-CoV, MERS-CoV and SARS-CoV-2 seem to less commonly affect children and to cause fewer symptoms and less severe disease in this age group compared with adults, and are associated with much lower case-fatality rates. Preliminary evidence suggests children are just as likely as adults to become infected with SARS-CoV-2 but are less likely to be symptomatic or develop severe symptoms. However, the importance of children in transmitting the virus remains uncertain. Children more often have gastrointestinal symptoms compared with adults. Most children with SARS-CoV present with fever, but this is not the case for the other novel CoVs. Many children affected by MERS-CoV are asymptomatic. The majority of children infected by novel CoVs have a documented household contact, often showing symptoms before them. In contrast, adults more often have a nosocomial exposure. In this review, we summarize epidemiologic, clinical and diagnostic findings, as well as treatment and prevention options for common circulating and novel CoVs infections in humans with a focus on infections in children.

Covid-19 and the digestive system

The novel coronavirus disease is currently causing a major pandemic. It is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a member of the Betacoronavirus genus that also includes the SARS-CoV and Middle East respiratory syndrome coronavirus. While patients typically present with fever and a respiratory illness, some patients also report gastrointestinal symptoms such as diarrhea, vomiting, and abdominal pain. Studies have identified the SARS-CoV-2 RNA in stool specimens of infected patients, and its viral receptor angiotensin converting enzyme 2 was found to be highly expressed in gastrointestinal epithelial cells. These suggest that SARS-CoV-2 can actively infect and replicate in the gastrointestinal tract. This has important implications to the disease management, transmission, and infection control. In this article, we review the important gastrointestinal aspects of the disease.

Virological assessment of hospitalized patients with COVID-2019

Coronavirus disease 2019 (COVID-19) is an acute infection of the respiratory tract that emerged in late 2019^1,2. Initial outbreaks in China involved 13.8% of cases with severe courses, and 6.1% of cases with critical courses³. This severe presentation may result from the virus using a virus receptor that is expressed predominantly in the lung^2,4; the same receptor tropism is thought to have determined the pathogenicity-but also aided in the control-of severe acute respiratory syndrome (SARS) in 2003⁵. However, there are reports of cases of COVID-19 in which the patient shows mild upper respiratory tract symptoms, which suggests the potential for pre- or oligosymptomatic transmission^6-8. There is an urgent need for information on virus replication, immunity and infectivity in specific sites of the body. Here we report a detailed virological analysis of nine cases of COVID-19 that provides proof of active virus replication in tissues of the upper respiratory tract. Pharyngeal virus shedding was very high during the first week of symptoms, with a peak at 7.11 × 10⁸ RNA copies per throat swab on day 4. Infectious virus was readily isolated from samples derived from the throat or lung, but not from stool samples-in spite of high concentrations of virus RNA. Blood and urine samples never yielded virus. Active replication in the throat was confirmed by the presence of viral replicative RNA intermediates in the throat samples. We consistently detected sequence-distinct virus populations in throat and lung samples from one patient, proving independent replication. The shedding of viral RNA from sputum outlasted the end of symptoms. Seroconversion occurred after 7 days in 50% of patients (and by day 14 in all patients), but was not followed by a rapid decline in viral load. COVID-19 can present as a mild illness of the upper respiratory tract. The confirmation of active virus replication in the upper respiratory tract has implications for the containment of COVID-19.

The presence of SARS-CoV-2 RNA in the feces of COVID-19 patients

In December 2019, coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in Wuhan, China, and has spread globally. However, the transmission route of SARS-CoV-2 has not been fully understood. In this study, we aimed to investigate SARS-CoV-2 shedding in the excreta of COVID-19 patients. Electronical medical records, including demographics, clinical characteristics, laboratory and radiological findings of enrolled patients were extracted and analyzed. Pharyngeal swab, stool, and urine specimens were collected and tested for SARS-CoV-2 RNA by real-time reverse transcription polymerase chain reaction. Viral shedding at multiple time points in specimens was recorded, and its correlation analyzed with clinical manifestations and the severity of illness. A total of 42 laboratory-confirmed patients were enrolled, 8 (19.05%) of whom had gastrointestinal symptoms. A total of 28 (66.67%) patients tested positive for SARS-CoV-2 RNA in stool specimens, and this was not associated with the presence of gastrointestinal symptoms and the severity of illness. Among them, 18 (64.29%) patients remained positive for viral RNA in the feces after the pharyngeal swabs turned negative. The duration of viral shedding from the feces after negative conversion in pharyngeal swabs was 7 (6-10) days, regardless of COVID-19 severity. The demographics, clinical characteristics, laboratory and radiologic findings did not differ between patients who tested positive and negative for SARS-CoV-2 RNA in the feces. Viral RNA was not detectable in urine specimens from 10 patients. Our results demonstrated the presence of SARS-CoV-2 RNA in the feces of COVID-19 patients and suggested the possibility of SARS-CoV-2 transmission via the fecal-oral route.

Possible effects of coronavurus infection (COVID-19) on the cardiovascular system

Acute viral respiratory infections can increase the risk of progression of a pre-existing condition, including a cardiovascular pathology. Life-threatening complications of Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) necessitate research into the cardiovascular effects of COVID-19 crucial for developing adequate treatment strategy for infected patients, especially those of advanced age. This article reviews the literature on the clinical and functional characteristics of patients with COVID-19, including those with poor outcomes. The article looks at the pathophysiological processes occurring in the cardiovascular system in the setting of SARS-CoV-2 infection, risk factors and death predictors. It also discusses continuation of therapy with angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in patients with COVID-19.