Presumed Asymptomatic Carrier Transmission of COVID-19
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Abstract:
This study describes possible transmission of novel coronavirus disease 2019 (COVID-19) from an asymptomatic Wuhan resident to 5 family members in Anyang, a Chinese city in the neighboring province of Hubei.Keywords:
Asymptomatic carrier
2019-20 coronavirus outbreak
Coronavirus
Betacoronavirus
Coronavirus Infections
From a total of 71 laboratory-confirmed cases, three presymptomatic patients and 10 patients with entirely asymptomatic infections were identified. In two of the three incubation period patients, the viral titer in the presymptomatic period was very high (Ct value < 20). The median number of days to first negative RT-PCR in the asymptomatic carriers was 4.5 (range 2.5–9), and all asymptomatic carriers reached a first RT-PCR Ct > 35 within 14 days after diagnosis. Patients who have COVID-19 may already be infectious before there are symptoms, and 14 days of isolation after diagnosis may be sufficient in entirely asymptomatic cases.
Asymptomatic carrier
Incubation period
2019-20 coronavirus outbreak
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Background: Coronavirus disease 2019 (COVID-19) has been highly epidemic in the whole world now. Asymptomatic transmission of severe acute respiratory coronavirus-2 (SARS-CoV-2)might pose challenges for disease control. Little information on its characteristics of asymptomatic COVID-19 carriers is available. This study aimed to clarify the clinical feature and follow-up data of asymptomatic COVID-19 carriers, We hope the information would help the management of asymptomatic COVID-19 carriers. Methods: This retrospective study included all asymptomatic COVID-19 carriers inThe First People's Hospital of Yueyang(Hunan,China) and Hunan Provincial People's Hospital (Changsha, China) between January 22 and March 26, 2020. The epidemiology ,clinical characteristic,laboratory data,chest CT and follow-up data of these cases were investigated. Results: 24 asymptomatic COVID-19 carriers were enrolled inThe First People's Hospital of Yueyang and Hunan Provincial People's Hospital between Jan 22, 2020 and Mar 26, 2020 . All patients had history of exposure to SARS-CoV-2. During the whole disease course, patients had no symptoms and most of laboratory findings were normal. The median period from contact to diagnosis was 9.6days(1-38days). The median period from diagnosis to discharge was 14.4 days (6-24 days). Following after discharge,all patients continued to be asymptomatic.5(20.83%) patients were admitted again because their specimens(4 throat swab and 1 feces) showed re-positive results in SARS-CoV-2 PCR. The re-positive time away from diagnosis(day) was from 23-53 days; the time from re-positive to re-negative RT-PCR of SARS-CoV-2 was 3-11 days. Conclusion: Asymptomatic COVID-19 carriers have favorable outcomes and should be closely monitored. We suggested post-discharge surveillance of them.
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Asymptomatic carrier
2019-20 coronavirus outbreak
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Background: With the ongoing outbreak of COVID-19 around the world, it has become a worldwide health concern. Aim of study: check a cluster or presence of asymptomatic carrier with an asymptomatic transmission of COVID-19. Material m during Conclusions Infectivity of some asymptomatic SARS-CoV-2 carriers might be weak. Effective prevention and control measures are helpful to prevent COVID-19 spread of asymptomatic carriers. The result of this study may alleviate parts of the public concern about asymptomatic infected people further longitudinal surveillance of these asymptomatic cases via virus nucleic acid testing are warranted.
Asymptomatic carrier
2019-20 coronavirus outbreak
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ABSTRACT We discovered a novel Betacoronavirus lineage A coronavirus, China Rattus coronavirus (ChRCoV) HKU24, from Norway rats in China. ChRCoV HKU24 occupied a deep branch at the root of members of Betacoronavirus 1 , being distinct from murine coronavirus and human coronavirus HKU1. Its unique putative cleavage sites between nonstructural proteins 1 and 2 and in the spike (S) protein and low sequence identities to other lineage A betacoronaviruses (βCoVs) in conserved replicase domains support ChRCoV HKU24 as a separate species. ChRCoV HKU24 possessed genome features that resemble those of both Betacoronavirus 1 and murine coronavirus, being closer to Betacoronavirus 1 in most predicted proteins but closer to murine coronavirus by G+C content, the presence of a single nonstructural protein (NS4), and an absent transcription regulatory sequence for the envelope (E) protein. Its N-terminal domain (NTD) demonstrated higher sequence identity to the bovine coronavirus (BCoV) NTD than to the mouse hepatitis virus (MHV) NTD, with 3 of 4 critical sugar-binding residues in BCoV and 2 of 14 contact residues at the MHV NTD/murine CEACAM1a interface being conserved. Molecular clock analysis dated the time of the most recent common ancestor of ChRCoV HKU24, Betacoronavirus 1 , and rabbit coronavirus HKU14 to about the year 1400. Cross-reactivities between other lineage A and B βCoVs and ChRCoV HKU24 nucleocapsid but not spike polypeptide were demonstrated. Using the spike polypeptide-based Western blot assay, we showed that only Norway rats and two oriental house rats from Guangzhou, China, were infected by ChRCoV HKU24. Other rats, including Norway rats from Hong Kong, possessed antibodies only against N protein and not against the spike polypeptide, suggesting infection by βCoVs different from ChRCoV HKU24. ChRCoV HKU24 may represent the murine origin of Betacoronavirus 1 , and rodents are likely an important reservoir for ancestors of lineage A βCoVs. IMPORTANCE While bats and birds are hosts for ancestors of most coronaviruses (CoVs), lineage A βCoVs have never been found in these animals and the origin of Betacoronavirus lineage A remains obscure. We discovered a novel lineage A βCoV, China Rattus coronavirus HKU24 (ChRCoV HKU24), from Norway rats in China with a high seroprevalence. The unique genome features and phylogenetic analysis supported the suggestion that ChRCoV HKU24 represents a novel CoV species, occupying a deep branch at the root of members of Betacoronavirus 1 and being distinct from murine coronavirus. Nevertheless, ChRCoV HKU24 possessed genome characteristics that resemble those of both Betacoronavirus 1 and murine coronavirus. Our data suggest that ChRCoV HKU24 represents the murine origin of Betacoronavirus 1 , with interspecies transmission from rodents to other mammals having occurred centuries ago, before the emergence of human coronavirus (HCoV) OC43 in the late 1800s. Rodents are likely an important reservoir for ancestors of lineage A βCoVs.
Betacoronavirus
Coronavirus
Bovine coronavirus
Mouse hepatitis virus
Coronaviridae
Lineage (genetic)
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In the current global coronavirus disease (COVID-19) pandemic, asymptomatic transmission of the causative agent, severe acute respiratory coronavirus-2 (SARS-CoV-2), poses a considerable challenge for disease control. Furthermore, information on the clinical characteristics of asymptomatic carriers is limited. Here, we aimed to clarify the clinical features and obtain follow-up data of asymptomatic carriers to assist in the clinical management of carriers. This retrospective study included all asymptomatic SARS-CoV-2 carriers diagnosed at the First People’s Hospital of Yueyang (Hunan, China) and Hunan Provincial People’s Hospital (Changsha, China) between January 22 and March 26, 2020. Data including the epidemiology, clinical characteristics, laboratory test results, and chest computed tomography status were collected, with a follow-up of these cases. A total of 24 asymptomatic carriers were enrolled at the First People’s Hospital of Yueyang and Hunan Provincial People’s Hospital between 22 January 2020 and 26 March 2020. All patients had previously been exposed to SARS-CoV-2. Over the monitored time, patients experienced no symptoms and most laboratory findings were normal. The median time from contact to diagnosis was 9.6 days (range: 1-38 days), while that from diagnosis to discharge was 14.4 days (range: 6-24 days). Following discharge, all patients remained asymptomatic. However, five patients (20.83%) were re-admitted because a polymerase chain reaction (PCR)-based re-test of their specimens (4 throat swabs and 1 feces) showed that they were positive for SARS-CoV-2. The time to re-testing positively varied from 23 to 53 days post-diagnosis. The time to re-testing negative for SARS-CoV-2 by real-time reverse transcription PCR after re-testing positive was 3 to 11 days. In conclusion, although asymptomatic carriers have favorable outcomes, they should be closely monitored. Also, clear guidelines need to be formulated and close surveillance is required for the management of asymptomatic carriers.
Asymptomatic carrier
Contact tracing
Pandemic
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Abstract Background: Previous studies have documented the clinical characteristics of patients with Coronavirus disease 2019(COVID-19) and presented evidence of person-to-person transmission. Limited data are available for patients with asymptomatic infections. Some asymptomatic carriers, whom we characterize as “exposers” or “infectors”, may be responsible for family clustering of COVID-19. Methods: A questionnaire survey and follow-up survey based on media reports were used to assess familial clustering of SARS-CoV-2 infection induced by asymptomatic exposers/infectors. Individual data were collected for all members of each tracked family. A transmission map was then drawn for each family. Results: Our study of 5 families indicated that individuals with no obvious symptoms of COVID-19, regardless of the PCR results, transmitted the virus to other family members who were community contained at home and had no contact with other infected individuals. There was one death case in Family No.3. Conclusion: Asymptomatic exposers/infectors of SARS-CoV-2 were all middle-aged (average age: 44.4 ± 14.9 years) who had no symptoms but had the ability to disseminate the virus. Medical staff participating in treatment of COVID-19 cases all had a high risk of infection, they should be quarantined so as to protect their families. The morbidity and mortality of Case 3.2 remind us that although these asymptomatic infected people have no symptoms, they are also infectious. It is not ruled out that the subsequent infected people are seriously ill or even die. Therefore, we should not take it lightly.
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Design of hACE2-based small peptide inhibitors against spike protein of SARS-CoV-2: a computational approach,
Coronavirus
2019-20 coronavirus outbreak
Betacoronavirus
Coronavirus Infections
Pandemic
Sars virus
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Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) quickly became a major epidemic threat in the whole China. We analysed SARS-Cov-2 infected cases from Tibetan Autonomous Prefecture, and noted divergent characteristics of these Tibetans infected cases compared to Han Chinese, characterizing by a considerable proportion of asymptomatic carriers (21.7%), and few symptomatic patients with initial symptom of fever (7.7%). Here, we did a descriptive study on clinical characteristics of 18 asymptomatic individuals with SARS-CoV-2 infection. The median age of these asymptomatic carriers was 31 years and one third of them were students, aged under 20 years. Notably, some of asymptomatic carriers had recognizable changes in radiological and laboratory indexes. Our finding indicates a potentially big number of SARS-CoV-2 asymptomatic carriers in prevalent area, highlighting a necessity of screening individuals with close contact of infected patients, for a better control on the spread of SARS-CoV-2 infection.
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Summary We propose the term “common cold coronaviruses,” or ccCoV, to describe the four human coronaviruses commonly associated with upper respiratory tract disease – coronaviruses 229E, OC43, NL63, and HKU1. This will differentiate these previously described coronaviruses from those causing more severe disease in humans – including the viruses severe acute respiraotry syndrome coronavirus (SARS-CoV), the Middle East respiratory syndrome coronavirus (MERS-CoV) and SARS-CoV-2.
Common cold
Coronavirus
Betacoronavirus
Coronavirus Infections
2019-20 coronavirus outbreak
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