News attention



20

2020

-

02

Scientific Research News | Research Progress of novel coronavirus Pneumonia (COVID-19) (20)


1. 2019-nCoV Epidemic Alert

■ On February 2, at the press conference of the joint prevention and control mechanism of the State Council, the host said, "Compared with the high point, on February 18, the number of new confirmed cases in a single day across the country dropped to less than 2,17 for the first time, the number of new confirmed cases outside Hubei Province dropped to less than 2000 for the first time, and the number of new deaths in a single day nationwide fell to less than 100 for the first time, achieving 'three firsts', and the epidemic situation has further changed for the better." In addition, for patients without fever symptoms to go to the hospital to see a doctor, take CT, do laboratory tests, how to do a good job of protection, Chinese Center for Disease Control and Prevention researcher Zhang Liubo said, "On this issue, I have six suggestions: First, if there is no fever symptoms of patients to the hospital, should try to avoid going to the fever clinic." Second, before going to the hospital, it is best to reduce the waiting time through online registration, appointment, etc. Third, when you go to the hospital, you can wear disposable medical mask level and above. Fourth, it is best not to touch the items and environmental surfaces in the hospital casually, and try to touch them as little as possible. Fifth, carry hand sanitizer with you, and remember to do hand hygiene after touching hospital public facilities, before touching your eyes, nose, and mouth with your hands, or when leaving the hospital. Sixth, wear gloves if possible. ”

On February 2, Xiang Yutao's team at the University of Macau published a newsletter entitled "Timely research papers about COVID-17 in China" online in The Lancet, a top international medical journal, pointing out that it hoped that the research community would strive to publish research results in English while also using Chinese to disseminate findings related to the COVID-19 outbreak. Publishing clinical studies in English helps facilitate knowledge exchange between Chinese scientists and scientists in other countries around the world. Spreading findings by Chinese facilitates the dissemination of this information to frontline healthcare professionals who need to understand the epidemiology and clinical features of COVID-19. This strategy will effectively improve the control strategy to ultimately control the virus and protect public health [19].

2. Advances in biological research of 2019-nCoV

■ On February 2, Professor Wang Fusheng, director of the National Infectious Disease Diagnosis and Treatment and Research Center of the Fifth Medical Center of the PLA General Hospital and academician of the Chinese Academy of Sciences, published the world's first pathology report of new coronary pneumonia patients online in the internationally renowned medical academic journal The Lancet Respiratory Medicine. The team's pathological analysis was not obtained by a complete autopsy, but by post-mortem biopsy, which is the same as the tissue biopsy procedure used in the clinic, except that the procedure is performed after the patient's death. The research team affirmed, "This study complies with the regulations of the National Health Commission and the Declaration of Helsinki. Our findings will contribute to understanding the pathogenesis of COVID and improving clinical strategies for the disease." ”

According to the paper, the patient, a 50-year-old male, was admitted on 2020 January 1 with symptoms such as fever, chills, cough, fatigue and shortness of breath. The patient reported a history of travel to Wuhan from 21 to 1 January, and on 8 January as the first day of illness, initially presenting with mild chills and dry cough, but did not seek immediate medical attention and worked until 10 January. Following the presentation, the patient's chest x-ray shows multiple patchy opacities in both lungs. The hospital took a sample of the patient's throat swab. On January 1 (the 14th day of onset), according to the RT-PCR test results of the Chinese Center for Disease Control and Prevention (CDC), the patient was diagnosed with new coronary pneumonia. On the afternoon of the 1th day of onset, at 21:1 Beijing time on January 22, the patient died. The team took samples from the patient's lung, liver, and heart tissue, and histological examination revealed bilateral diffuse alveolar damage with cell-fibrous exudates. The right lung shows significant lung cell shedding and hyaline membrane formation, indicating acute respiratory distress syndrome (ARDS). The left lung tissue shows pulmonary edema and the formation of a transparent membrane of the lung, indicating that the patient has early ARDS.

The research team mentioned that the pathological features of the new coronary pneumonia are very similar to those of SARS and Middle East respiratory syndrome (MERS) patients. In addition, liver samples from patients with novel coronary pneumonia showed moderate microvascular steteaosis, as well as mild hepatic lobular and portal vein activity, suggesting that the injury may be caused by coronavirus infection or drug-induced liver injury. There is a small amount of cellular mononuclear inflammatory infiltration in the heart tissue space, but no other substantial damage in the heart tissue. The research team performed flow cytometry analysis on the patient's peripheral blood. The results showed that the number of CD4 and CD8 T cells in the blood was greatly reduced, but they were overactivated. The research team concluded that in this severe case of new coronavirus, their clinical and pathological findings can not only help determine the cause of death, but also provide new insights into the pathogenesis of new coronavirus-related pneumonia, which may help doctors develop timely treatment strategies for similar severe patients and reduce mortality.

A recent study from the University of South Carolina School of Public Health, published online on preprint platform medRxiv, titled Tobacco-use disparity in gene expression of ACE2, the receptor of 2019-nCov. After analyzing two large RNA-seq databases and two DNA chip databases of normal lung tissue, and studying the expression of ACE224 genes in 2019 receptors for the new coronavirus (2-nCoV) covering samples of different races, ages, genders and smoking conditions, the researchers found that smokers may be more susceptible to new coronary pneumonia. Different races, ages, and genders are the same in contracting the new crown pneumonia, and it is not that Asians are more susceptible. Researchers believe that this also explains to some extent why COVID-19 occurs more in middle-aged and older men. Because smokers may be more susceptible to the novel coronavirus. Therefore, the authors recommend that smoking history should be considered when diagnosing susceptible populations and developing standardized treatment regimens [2].

■ On February 2, Kristian G. Andersen of the Scripps Research Institute and W. Ian Lippin of Columbia University jointly published an article entitled "The Proximal Origin of SARS-CoV-17" on virological.org websites. In the article, the researchers conducted a functional and structural comparative analysis of the characteristics of two suspected human interventions in the genome of the novel coronavirus, which provided a wealth of evidence that the novel coronavirus is not a leak of laboratory engineering, but a product of the natural evolution of the virus.

Phenylalanine (F) of residue 2019 in the 486-nCoV S protein corresponds to L472 in the SARS-CoV Urbani strain. It is worth noting that in SARS-CoV cell culture experiments, L472 mutated to phenylalanine (L472F), although this mutation will significantly increase the affinity of the virus for binding to human receptors, but this mutation has long existed in the natural host of bats and pangolin-related coronaviruses (several SARS-like coronaviruses of bats also have phenylalanine in corresponding positions), so it cannot be said that this is a deliberately artificially generated mutation. Moreover, previous studies have shown that this mutation is not the strongest mutation method. The other 5 amino acids may also lead to an increase in affinity, and if it is really a conspiracy of a molecular biologist, then he can actually use existing technology to mutate the other 5 amino acids into more serious combinations. Thus, the spike of 2019-nCoV appears to be the result of natural selection on human or humanoid ACE2 receptors, rather than the product of genetic engineering. On the other hand, the 2019-nCoV virus has many detailed changes in the composition of nucleic acid sequences with any known coronavirus, which also shows that this virus is not a virus generated by a known template modification. Finally, the article also mentioned that it is imperative to control the ongoing outbreak of the novel coronavirus and continue to find other, more direct intermediate hosts to prevent another outbreak.

3. 2019-nCoV epidemiological study

■ On February 2, Zhang Wenhong, director of the Department of Infectious Diseases of Huashan Hospital, released a prospective study based on 17 suspected patients of new coronary pneumonia (from cities in East China, 53 were finally diagnosed and 20 excluded) on medRxiv, providing important information for non-epidemic areas to further optimize the diagnosis process of new coronary pneumonia, the following are the main data and opinions:
33. It is not only possible to use whether there are other bacterial infections for suspected patients (here is mainly chest CT abnormalities, and patients with a history of contact in Wuhan) were excluded;
1. In addition to CT, nucleic acid diagnosis is required for further verification in non-epidemic areas;
2. High missed diagnosis rate based on reverse transcription quantitative PCR method, while high diagnostic sensitivity and accuracy based on sequencing;
3. The virus concentration of the new coronary pneumonia throat swab sample (closely related to the intensity of infection) is not directly related to the severity of symptoms;
4. Non-epidemic areas need repeated nucleic acid sampling combined with CT and other technologies to confirm the diagnosis, and even multi-time points and multi-sample sampling for key cases are confirmed by sequencing [5].

■ Chih-Cheng Lai et al. in Taiwan, China, recently published a review article on epidemiology, summarizing the data and characteristics of epidemic development in China and around the world since the outbreak [4].

Bibliography:

1. Xiang Y-T, Li W, Zhang Q, et al. Timely research papers about COVID-19 in China. The Lancet.

2. Cai G. Bulk and single-cell transcriptomics identify tobacco-use disparity in lung gene expression of ACE2, the receptor of 2019-nCov. medRxiv 2020:2020.02.05.20020107.

3. Ai J-W, Zhang H-C, Xu T, et al. Optimizing diagnostic strategy for novel coronavirus pneumonia, a multi-center study in Eastern China. medRxiv 2020:2020.02.13.20022673.

4. Lai C-C, Shih T-P, Ko W-C, Tang H-J, Hsueh P-R. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and corona virus disease-2019 (COVID-19): the epidemic and the challenges. International Journal of Antimicrobial Agents 2020:105924.

 

Feed | Pingshan Biomedical R&D and Transformation Center, Scientific Research Department

Edit | Bao la