Journal of Medical Virology

The recent emergence of a novel coronavirus (2019‐nCoV), which is causing an outbreak of unusual viral pneumonia in patients in Wuhan, a central city in China, is another warning of the risk of CoVs posed to public health. In this minireview, we provide a brief introduction of the general features of CoVs and describe diseases caused by different CoVs in humans and animals. This review will help understand the biology and potential risk of CoVs that exist in richness in wildlife such as bats.

Theo sau hội chứng suy hô hấp cấp tính nặng coronavirus (SARS‐CoV) và hội chứng hô hấp Trung Đông coronavirus (MERS‐CoV), một loại coronavirus gây bệnh nặng khác được gọi là SARS‐CoV-2 (trước đây được biết đến với tên 2019‐nCoV) đã xuất hiện vào tháng 12 năm 2019 tại Vũ Hán, Trung Quốc, và lan nhanh ra khắp thế giới. Virus này có trình tự giống cao với SARS‐CoV và gây ra bệnh viêm phổi coronavirus cấp tính nguy hiểm chết người năm 2019 (COVID‐19) với các triệu chứng lâm sàng tương tự như các triệu chứng báo cáo cho SARS‐CoV và MERS‐CoV. Triệu chứng đặc trưng nhất của bệnh nhân COVID‐19 là suy hô hấp, và hầu hết các bệnh nhân nhập viện chăm sóc đặc biệt không thể thở tự phát. Ngoài ra, một số bệnh nhân COVID-19 cũng có biểu hiện triệu chứng thần kinh, như đau đầu, buồn nôn và nôn. Nhiều bằng chứng cho thấy rằng các coronavirus không chỉ giới hạn ở đường hô hấp mà còn có thể xâm nhập hệ thần kinh trung ương gây ra các bệnh thần kinh. Nhiễm trùng SARS‐CoV đã được báo cáo ở não của cả bệnh nhân và động vật thí nghiệm, nơi thân não bị nhiễm nghiêm trọng. Hơn nữa, một số coronavirus đã được chứng minh có khả năng lan truyền qua đường kết nối synapse đến trung tâm hô hấp tim mạch từ các thụ thể cơ học và hóa học trong phổi và đường hô hấp dưới. Xét sự tương đồng cao giữa SARS‐CoV và SARS‐CoV-2, vẫn cần làm rõ liệu khả năng xâm nhập tiềm tàng của SARS‐CoV-2 có phải là phần nào chịu trách nhiệm cho suy hô hấp cấp tính của bệnh nhân COVID-19 hay không. Nhận thức về điều này có thể mang ý nghĩa chỉ đạo cho công tác phòng ngừa và điều trị suy hô hấp do SARS‐CoV-2 gây ra.

Coronaviruses (CoVs) are by far the largest group of known positive‐sense RNA viruses having an extensive range of natural hosts. In the past few decades, newly evolved Coronaviruses have posed a global threat to public health. The immune response is essential to control and eliminate CoV infections, however, maladjusted immune responses may result in immunopathology and impaired pulmonary gas exchange. Gaining a deeper understanding of the interaction between Coronaviruses and the innate immune systems of the hosts may shed light on the development and persistence of inflammation in the lungs and hopefully can reduce the risk of lung inflammation caused by CoVs. In this review, we provide an update on CoV infections and relevant diseases, particularly the host defense against CoV‐induced inflammation of lung tissue, as well as the role of the innate immune system in the pathogenesis and clinical treatment.

By 27 February 2020, the outbreak of coronavirus disease 2019 (COVID‐19) caused 82 623 confirmed cases and 2858 deaths globally, more than severe acute respiratory syndrome (SARS) (8273 cases, 775 deaths) and Middle East respiratory syndrome (MERS) (1139 cases, 431 deaths) caused in 2003 and 2013, respectively. COVID‐19 has spread to 46 countries internationally. Total fatality rate of COVID‐19 is estimated at 3.46% by far based on published data from the Chinese Center for Disease Control and Prevention (China CDC). Average incubation period of COVID‐19 is around 6.4 days, ranges from 0 to 24 days. The basic reproductive number (R₀) of COVID‐19 ranges from 2 to 3.5 at the early phase regardless of different prediction models, which is higher than SARS and MERS. A study from China CDC showed majority of patients (80.9%) were considered asymptomatic or mild pneumonia but released large amounts of viruses at the early phase of infection, which posed enormous challenges for containing the spread of COVID‐19. Nosocomial transmission was another severe problem. A total of 3019 health workers were infected by 12 February 2020, which accounted for 3.83% of total number of infections, and extremely burdened the health system, especially in Wuhan. Limited epidemiological and clinical data suggest that the disease spectrum of COVID‐19 may differ from SARS or MERS. We summarize latest literatures on genetic, epidemiological, and clinical features of COVID‐19 in comparison to SARS and MERS and emphasize special measures on diagnosis and potential interventions. This review will improve our understanding of the unique features of COVID‐19 and enhance our control measures in the future.

Noroviruses are major agents of viral gastroenteritis worldwide. The infectivity of Norwalk virus, the prototype norovirus, has been studied in susceptible human volunteers. A new variant of the hit theory model of microbial infection was developed to estimate the variation in Norwalk virus infectivity, as well as the degree of virus aggregation, consistent with independent (electron microscopic) observations. Explicit modeling of viral aggregation allows us to express virus infectivity per single infectious unit (particle). Comparison of a primary and a secondary inoculum showed that passage through a human host does not change Norwalk virus infectivity. We estimate the average probability of infection for a single Norwalk virus particle to be close to 0.5, exceeding that reported for any other virus studied to date. Infected subjects had a dose‐dependent probability of becoming ill, ranging from 0.1 (at a dose of 10³ NV genomes) to 0.7 (at 10⁸ virus genomes). A norovirus dose response model is important for understanding its transmission and essential for development of a quantitative risk model. Norwalk virus is a valuable model system to study virulence because genetic factors are known for both complete and partial protection; the latter can be quantitatively described as heterogeneity in dose response models. J. Med. Virol. 80:1468–1476, 2008. © 2008 Wiley‐Liss, Inc.

In this study, we collected a total of 610 hospitalized patients from Wuhan between February 2, 2020, and February 17, 2020. We reported a potentially high false negative rate of real‐time reverse‐transcriptase polymerase chain reaction (RT‐PCR) testing for SARS‐CoV‐2 in the 610 hospitalized patients clinically diagnosed with COVID‐19 during the 2019 outbreak. We also found that the RT‐PCR results from several tests at different points were variable from the same patients during the course of diagnosis and treatment of these patients. Our results indicate that in addition to the emphasis on RT‐PCR testing, clinical indicators such as computed tomography images should also be used not only for diagnosis and treatment but also for isolation, recovery/discharge, and transferring for hospitalized patients clinically diagnosed with COVID‐19 during the current epidemic. These results suggested the urgent needs for the standard of procedures of sampling from different anatomic sites, sample transportation, optimization of RT‐PCR, serology diagnosis/screening for SARS‐CoV‐2 infection, and distinct diagnosis from other respiratory diseases such as fluenza infections as well.

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.

We aimed to systematically review the clinical characteristics of coronavirus disease 2019 (COVID‐19). Seven databases were searched to collect studies about the clinical characteristics of COVID‐19 from January 1, 2020 to February 28, 2020. Then, meta‐analysis was performed by using Stata12.0 software. A total of 38 studies involving 3062 COVID‐19 patients were included. Meta‐analysis showed that a higher proportion of infected patients was male (56.9%). The incidence rate of respiratory failure or acute respiratory distress syndrome was 19.5% and the fatality rate was 5.5%. Fever (80.4%), fatigue (46%), cough (63.1%), and expectoration (41.8%) were the most common clinical manifestations. Other common symptoms included muscle soreness (33%), anorexia (38.8%), chest tightness (35.7%), shortness of breath (35%), dyspnea (33.9%). Minor symptoms included nausea and vomiting (10.2%), diarrhea (12.9%), headache (15.4%), pharyngalgia (13.1%), shivering (10.9%), and abdominal pain (4.4%). The proportion of patients that was asymptomatic was 11.9%. Normal leukocyte counts (69.7%), lymphopenia (56.5%), elevated C‐reactive protein levels (73.6%), elevated ESR (65.6%), and oxygenation index decreased (63.6%) were observed in most patients. About 37.2% of patients were found with elevated D‐dimer, 25.9% of patients with leukopenia, along with abnormal levels of liver function (29%), and renal function (25.5%). Other findings included leukocytosis (12.6%) and elevated procalcitonin (17.5%). Only 25.8% of patients had lesions involving a single lung and 75.7% of patients had lesions involving bilateral lungs. The most commonly experienced symptoms of COVID‐19 patients were fever, fatigue, cough, and expectoration. A relatively small percentage of patients were asymptomatic. Most patients showed normal leucocytes counts, lymphopenia, elevated levels of C‐reactive protein and ESR. Bilateral lung involvement was common.