Asymptomatic carrier state,acute respiratory disease,and pneumonia due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): Facts and myths

Since the emergence of coronavirus disease 2019 (COVID-19) (formerly known as the 2019 novel coronavirus [2019-nCoV]) in Wuhan, China in December 2019, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), more than 75,000 cases have been reported in 32 countries/regions, resulting in more than 2000 deaths worldwide. Despite the fact that most COVID-19 cases and mortalities were reported in China, the WHO has declared this outbreak as the sixth public health emergency of international concern. The COVID-19 can present as an asymptomatic carrier state, acute respiratory disease, and pneumonia. Adults represent the population with the highest infection rate; however, neonates, children, and elderly patients can also be infected by SARS-CoV-2. In addition, nosocomial infection of hospitalized patients and healthcare workers, and viral transmission from asymptomatic carriers are possible. The most common finding on chest imaging among patients with pneumonia was ground-glass opacity with bilateral involvement. Severe cases are more likely to be older patients with underlying comorbidities compared to mild cases. Indeed, age and disease severity may be correlated with the outcomes of COVID-19. To date, effective treatment is lacking; however, clinical trials investigating the efficacy of several agents, including remdesivir and chloroquine, are underway in China. Currently, effective infection control intervention is the only way to prevent the spread of SARS-CoV-2.     

Coronavirus disease 2019: What we know?

In late December 2019, a cluster of unexplained pneumonia cases has been reported in Wuhan, China. A few days later, the causative agent of this mysterious pneumonia was identified as a novel coronavirus. This causative virus has been temporarily named as severe acute respiratory syndrome coronavirus 2 and the relevant infected disease has been named as coronavirus disease 2019 (COVID-19) by the World Health Organization, respectively. The COVID-19 epidemic is spreading in China and all over the world now. The purpose of this review is primarily to review the pathogen, clinical features, diagnosis, and treatment of COVID-19, but also to comment briefly on the epidemiology and pathology based on the current evidence.     

Genomic characterization and phylogenetic analysis of SARS-COV-2 in Italy

This report describes the isolation, molecular characterization, and phylogenetic analysis of the first three complete genomes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) isolated from three patients involved in the first outbreak of COVID-19 in Lombardy, Italy. Early molecular epidemiological tracing suggests that SARS-CoV-2 was present in Italy weeks before the first reported cases of infection.     

Extrapulmonary and atypical clinical presentations of COVID-19

The novel coronavirus (SARS-CoV2) has led to an outbreak of multiple cases of pneumonia in Wuhan city in December 2019. The disease caused by this virus was named coronavirus disease 2019 or “COVID-19”, which was declared by the World Health Organization as a global pandemic in March 2020. It typically presents with respiratory symptoms and febrile illness. However, there are few reported extrapulmonary and atypical presentations, such as hemoptysis, cardiac, neurological, gastrointestinal, ocular, and cutaneous manifestations, as well as venous and arterial thrombosis. Lack of awareness of these presentations might lead to misdiagnosis, delayed diagnosis, and isolation of suspected patients which increases the risk of transmission of infection between patients and doctors. All these issues will be discussed in this review.     

Analyzing the epidemiological outbreak of COVID-19: A visual exploratory data analysis approach

There is an obvious concern globally regarding the fact about the emerging coronavirus 2019 novel coronavirus (2019-nCoV) as a worldwide public health threat. As the outbreak of COVID-19 causes by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) progresses within China and beyond, rapidly available epidemiological data are needed to guide strategies for situational awareness and intervention. The recent outbreak of pneumonia in Wuhan, China, caused by the SARS-CoV-2 emphasizes the importance of analyzing the epidemiological data of this novel virus and predicting their risks of infecting people all around the globe. In this study, we present an effort to compile and analyze epidemiological outbreak information on COVID-19 based on the several open datasets on 2019-nCoV provided by the Johns Hopkins University, World Health Organization, Chinese Center for Disease Control and Prevention, National Health Commission, and DXY. An exploratory data analysis with visualizations has been made to understand the number of different cases reported (confirmed, death, and recovered) in different provinces of China and outside of China. Overall, at the outset of an outbreak like this, it is highly important to readily provide information to begin the evaluation necessary to understand the risks and begin containment activities.     

Encephalitic syndrome and anosmia in COVID‐19: Do these clinical presentations really reflect SARS‐CoV‐2 neurotropism? A theory based on the review of 25 COVID‐19 cases

Since the discovery of coronavirus disease 2019 (COVID‐19), a disease caused by the new coronavirus severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), the pathology showed different faces. There is an increasing number of cases described as (meningo)encephalitis although evidence often lacks. Anosmia, another atypical form of COVID‐19, has been considered as testimony of the potential of neuroinvasiveness of SARS‐CoV‐2, though this hypothesis remains highly speculative. We did a review of the cases reported as brain injury caused by SARS‐CoV‐2. Over 98 papers found, 21 were analyzed. Only four publications provided evidence of the presence of SARS‐CoV‐2 within the central nervous system (CNS). When facing acute neurological abnormalities during an infectious episode it is often difficult to disentangle neurological symptoms induced by the brain infection and those due to the impact of host immune response on the CNS. Cytokines release can disturb neural cells functioning and can have in the most severe cases vascular and cytotoxic effects. An inappropriate immune response can lead to the production of auto‐antibodies directed toward CNS components. In the case of proven SARS‐CoV‐2 brain invasion, the main hypothesis found in the literature focus on a neural pathway, especially the direct route via the nasal cavity, although the virus is likely to reach the CNS using other routes. Our ability to come up with hypotheses about the mechanisms by which the virus might interact with the CNS may help to keep in mind that all neurological symptoms observed during COVID‐19 do not always rely on CNS viral invasion.     

Composition and divergence of coronavirus spike proteins and host ACE2 receptors predict potential intermediate hosts of SARS-CoV-2

From the beginning of 2002 and 2012, severe respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) crossed the species barriers to infect humans, causing thousands of infections and hundreds of deaths, respectively. Currently, a novel coronavirus (SARS-CoV-2), which has become the cause of the outbreak of Coronavirus Disease 2019 (COVID-19), was discovered. Until 18 February 2020, there were 72 533 confirmed COVID-19 cases (including 10 644 severe cases) and 1872 deaths in China. SARS-CoV-2 is spreading among the public and causing substantial burden due to its human-to-human transmission. However, the intermediate host of SARS-CoV-2 is still unclear. Finding the possible intermediate host of SARS-CoV-2 is imperative to prevent further spread of the epidemic. In this study, we used systematic comparison and analysis to predict the interaction between the receptor-binding domain (RBD) of coronavirus spike protein and the host receptor, angiotensin-converting enzyme 2 (ACE2). The interaction between the key amino acids of S protein RBD and ACE2 indicated that, other than pangolins and snakes, as previously suggested, turtles (Chrysemys picta bellii, Chelonia mydas, and Pelodiscus sinensis) may act as the potential intermediate hosts transmitting SARS-CoV-2 to humans.     

Overlapping and discrete aspects of the pathology and pathogenesis of the emerging human pathogenic coronaviruses SARS-CoV,MERS-CoV,and 2019-nCoV

First reported from Wuhan, The People's Republic of China, on 31 December 2019, the ongoing outbreak of a novel coronavirus (2019-nCoV) causes great global concerns. Based on the advice of the International Health Regulations Emergency Committee and the fact that to date 24 other countries also reported cases, the WHO Director-General declared that the outbreak of 2019-nCoV constitutes a Public Health Emergency of International Concern on 30 January 2020. Together with the other two highly pathogenic coronaviruses, the severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), 2019-nCov and other yet to be identified coronaviruses pose a global threat to public health. In this mini-review, we provide a brief introduction to the pathology and pathogenesis of SARS-CoV and MERS-CoV and extrapolate this knowledge to the newly identified 2019-nCoV.     

Understanding of COVID-19 based on current evidence

Since December 2019, a series of unexplained pneumonia cases have been reported in Wuhan, China. On 12 January 2020, the World Health Organization (WHO) temporarily named this new virus as the 2019 novel coronavirus (2019-nCoV). On 11 February 2020, the WHO officially named the disease caused by the 2019-nCoV as coronavirus disease (COVID-19). The COVID-19 epidemic is spreading all over the world, especially in China. Based on the published evidence, we systematically discuss the characteristics of COVID-19 in the hope of providing a reference for future studies and help for the prevention and control of the COVID-19 epidemic.     

Impact of COVID-19 on maternal and neonatal outcomes: a systematic review and meta-analysis

BackgroundPrevious outbreaks of severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) and Middle East respiratory syndrome coronavirus (MERS-CoV) have been associated with unfavourable pregnancy outcomes. SARS-CoV-2 belongs to the human coronavirus family, and since this infection shows a pandemic trend it will involve many pregnant women.AimsThis systematic review and meta-analysis aimed to assess the impact of coronavirus disease 19 (COVID-19) on maternal and neonatal outcomes.SourcesPubMed, EMBASE, MedRxiv, Scholar, Scopus, and Web of Science databases were searched up to 8th May 2020. Articles focusing on pregnancy and perinatal outcomes of COVID-19 were eligible. Participants were pregnant women with COVID-19.ContentThe meta-analysis was conducted following the PRISMA and MOOSE reporting guidelines. Bias risk was assessed using the Joanna Briggs Institute (JBI) manual. The protocol was registered with PROSPERO (CRD42042020184752). Twenty-four articles, including 1100 pregnancies, were selected. The pooled prevalence of pneumonia was 89% (95%CI 70–100), while the prevalence of women admitted to the intensive care unit was 8% (95%CI 1–20). Three stillbirths and five maternal deaths were reported. A pooled prevalence of 85% (95%CI 72–94) was observed for caesarean deliveries. There were three neonatal deaths. The prevalence of COVID-19-related admission to the neonatal intensive care unit was 2% (95%CI 0–6). Nineteen out of 444 neonates were positive for SARS-CoV-2 RNA at birth. Elevated levels of IgM and IgG Serum antibodies were reported in one case, but negative swab.ImplicationsAlthough adverse outcomes such as ICU admission or patient death can occur, the clinical course of COVID-19 in most women is not severe, and the infection does not significantly influence the pregnancy. A high caesarean delivery rate is reported, but there is no clinical evidence supporting this mode of delivery. Indeed, in most cases the disease does not threaten the mother, and vertical transmission has not been clearly demonstrated. Therefore, COVID-19 should not be considered as an indication for elective caesarean section.     

Coronavirus disease (COVID-19) and neonate: What neonatologist need to know

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cause china epidemics with high morbidity and mortality, the infection has been transmitted to other countries. About three neonates and more than 230 children cases are reported. The disease condition of the main children was mild. There is currently no evidence that SARS-CoV-2 can be transmitted transplacentally from mother to the newborn. The treatment strategy for children with Coronavirus disease (COVID-19) is based on adult experience. Thus far, no deaths have been reported in the pediatric age group. This review describes the current understanding of COVID-19 infection in newborns and children.     

Epidemiological and clinical characteristics of discharged patients infected with SARS-CoV-2 on the Qinghai Plateau

Since the outbreak of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Wuhan, a series of confirmed cases of COVID-19 were found on the Qinghai-Tibet plateau. We aimed to describe the epidemiological, clinical characteristics, and outcomes of all confirmed cases in Qinghai, a province at high altitude. The region had no sustained local transmission. Of all 18 patients with confirmed SARS-CoV-2 infection, 15 patients comprising four transmission clusters were identified. Three patients were infected by direct contact without travel history to Wuhan. Of 18 patients, 10 patients showed bilateral pneumonia and two patients showed no abnormalities. Three patients with comorbidities such as hypertension, liver diseases, or diabetes developed severe illness. High C-reactive protein levels and elevations of both alanine aminotransferase and aspartate aminotransferase were observed in three severely ill patients on admission. All 18 patients were eventually discharged, including the three severe patients who recovered after treatment with noninvasive mechanical ventilation, convalescent plasma, and other therapies. Our findings confirmed human-to-human transmission of SARS-CoV-2 in clusters. Patients with comorbidities are more likely to develop severe illness.     

Pan-coronavirus fusion inhibitors to combat COVID-19 and other emerging coronavirus infectious diseases

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the currently ongoing coronavirus disease 2019 (COVID-19) pandemic, has posed a serious threat to global public health. Recently, several SARS-CoV-2 variants of concern (VOCs) have emerged and caused numerous cases of reinfection in convalescent COVID-19 patients, as well as breakthrough infections in vaccinated individuals. This calls for the development of broad-spectrum antiviral drugs to combat SARS-CoV-2 and its VOCs. Pan-coronavirus fusion inhibitors, targeting the conserved heptad repeat 1 (HR1) in spike protein S2 subunit, can broadly and potently inhibit infection of SARS-CoV-2 and its variants, as well as other human coronaviruses. In this review, we summarized the most recent development of pan-coronavirus fusion inhibitors, such as EK1, EK1C4, and EKL1C, and highlighted their potential application in combating current COVID-19 infection and reinfection, as well as future emerging coronavirus infectious diseases.     

The neuroinvasive potential of SARS-CoV2 may play a role in the respiratory failure of COVID-19 patients

Following the severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), another highly pathogenic coronavirus named SARS-CoV-2 (previously known as 2019-nCoV) emerged in December 2019 in Wuhan, China, and rapidly spreads around the world. This virus shares highly homological sequence with SARS-CoV, and causes acute, highly lethal pneumonia coronavirus disease 2019 (COVID-19) with clinical symptoms similar to those reported for SARS-CoV and MERS-CoV. The most characteristic symptom of patients with COVID-19 is respiratory distress, and most of the patients admitted to the intensive care could not breathe spontaneously. Additionally, some patients with COVID-19 also showed neurologic signs, such as headache, nausea, and vomiting. Increasing evidence shows that coronaviruses are not always confined to the respiratory tract and that they may also invade the central nervous system inducing neurological diseases. The infection of SARS-CoV has been reported in the brains from both patients and experimental animals, where the brainstem was heavily infected. Furthermore, some coronaviruses have been demonstrated able to spread via a synapse-connected route to the medullary cardiorespiratory center from the mechanoreceptors and chemoreceptors in the lung and lower respiratory airways. Considering the high similarity between SARS-CoV and SARS-CoV2, it remains to make clear whether the potential invasion of SARS-CoV2 is partially responsible for the acute respiratory failure of patients with COVID-19. Awareness of this may have a guiding significance for the prevention and treatment of the SARS-CoV-2-induced respiratory failure.     

Immunopathology and immunotherapeutic strategies in severe acute respiratory syndrome coronavirus 2 infection

The outbreak of coronavirus disease 2019 (COVID‐19) and pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has become a major concern globally. As of 14 April 2020, more than 1.9 million COVID‐19 cases have been reported in 185 countries. Some patients with COVID‐19 develop severe clinical manifestations, while others show mild symptoms, suggesting that dysregulation of the host immune response contributes to disease progression and severity. In this review, we have summarized and discussed recent immunological studies focusing on the response of the host immune system and the immunopathology of SARS‐CoV‐2 infection as well as immunotherapeutic strategies for COVID‐19. Immune evasion by SARS‐CoV‐2, functional exhaustion of lymphocytes, and cytokine storm have been discussed as part of immunopathology mechanisms in SARS‐CoV‐2 infection. Some potential immunotherapeutic strategies to control the progression of COVID‐19, such as passive antibody therapy and use of interferon αβ and IL‐6 receptor (IL‐6R) inhibitor, have also been discussed. This may help us to understand the immune status of patients with COVID‐19, particularly those with severe clinical presentation, and form a basis for further immunotherapeutic investigations.     

β属人冠状病毒感染研究进展

β属人冠状病毒(human coronavirus,HCoV)包括HCoV-OC43、HCoV-HKU1、严重急性呼吸综合征冠状病毒(severe acute respiratory syndrome coronavirus,SARS-CoV)、中东呼吸综合征冠状病毒(Middle East respiratory syndrome coronavirus,MERS-CoV)和2019新型冠状病毒(2019 novel coronavirus,2019-nCoV),其中SARS-CoV、MERS-CoV和2019-nCoV为高致病性HCoV,其跨种传播和流行对人类造成重大危害,对全球公共卫生及经济造成巨大损失,但相对于成人病例,儿童感染病例较少、临床表现较轻、预后较好,原因尚不清楚。本文对5种β属HCoV感染特点进行综述,比较儿童与成人病例的异同点并探讨其可能原因,以期为全面认识β属HCoV感染提供参考信息。     

Possible transmission of COVID-19 epidemic by a dog as a passive mechanical carrier of SARS-CoV-2, Chongqing,China, 2022

An outbreak of coronavirus disease 2019 (COVID-19) was reported in Yongchuan district of Chongqing, China in March 2022, while the source was unknown. We aimed to investigate the origin and transmission route of the virus in the outbreak. We conducted field investigations for all cases and collected their epidemiological and clinical data. We performed gene sequencing and phylogenetic analysis for the cases, and draw the epidemic curve and the case relationship chart to analyze interactions and possible transmission mode of the outbreak. A total of 11 cases of COVID-19, including 5 patients and 6 asymptomatic cases were laboratory-confirmed in the outbreak. The branch of the virus was Omicron BA.2 which was introduced into Yongchuan district by a traveler in early March. Patient F and asymptomatic case G had never contact with other positive-infected individuals, but close contact with their pet dog that sniffed the discarded cigarette butts and stepped on the sputum of patient B. Laboratory test results showed that the dog hair and kennel were positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the 10 isolates were highly homologous to an epidemic strain in a province of China. The investigation suggested that the contaminated dog by SARS-CoV-2 can act as a passive mechanical carrier of the virus and might transmit the virus to humans through close contact. Our findings suggest that during the COVID-19 pandemic, increasing hygiene measures and hand washing after close contact with pets is essential to minimize the risk of community spread of the virus.