Detection and analysis of nucleic acid in various biological samples of COVID-19 patients.
COVID-19 (corona virus disease 2019) is a kind of acute severe pneumonia caused by 2019-nCoV (2019-nCoV) infection. Since December 2019, it has been found in Wuhan, Hubei Province, and then spread to the whole country. Some parts of the world also showed an outbreak trend [1-3]. Real-time fluorescence quantitative reverse transcriptase polymerase chain reaction (reverse transcriptase-polymerase chain reaction,RT-PCR) and viral gene sequencing are the gold standard for the diagnosis of COVID-19. At present, upper respiratory tract nasopharyngeal swabs are mostly used as nucleic acid detection samples in China, but the positive rate is low. However, there are few reports on clinical application of 2019-nCoV nucleic acid detection in other biological samples.
| The East Section of Renmin Hospital of Wuhan University is a designated COVID-19 hospital in Wuhan City, Hubei Province, China. This observation study included 132 patients diagnosed with COVID-19 in the infectious disease areas of the East Section of Renmin Hospital of Wuhan University from 2020.1.31 to 2020.2.29. COVID-19 diagnostic criteria: according to China's ⟪pneumonia diagnosis and treatment Program of novel coronavirus infection (trial version 7) ⟫, in accordance with the relevant epidemiological and clinical manifestations, nasopharyngeal swabs real-time fluorescence RT-PCR detection of 2019-nCoV nucleic acid positive, COVID-19 cases were divided into mild, ordinary, severe and severe [1]. The nasopharyngeal swabs of 132 cases of COVID-19 were positive for 2019-nCoV nucleic acid on admission, including 72 males and 60 females, with an average age of 66.7 ± 9.1 years, including 80 cases of common type, 44 cases of severe type and 8 cases of critical type. During the period of admission, under the condition of tertiary protection, nasopharyngeal swabs, sputum, blood, feces and anal swabs of COVID-19 cases were collected many times in the isolation ward for 2019-nCoV nucleic acid detection. All biological samples are sealed and transferred to the laboratory in strict accordance with the standard process. The RT-PCR test kits (BioGerm) were recommended by the Chinese Center for Disease Control and Prevention. The same technician and brand of test kit was used for all RT-PCR testing reported; both internal controls and negative controls were routinely performed with each batch of tests.
| 132 the results of 2019-nCoV nucleic acid test of various biological samples during the treatment of confirmed COVID-19 cases are as follows: the positive rate of 2019-nCoV nucleic acid test of nasopharyngeal swab is 38.13% (180/472 times), the positive rate of 2019-nCoV nucleic acid test of sputum is 48.68% (148/304 times), the positive rate of blood 2019-nCoV nucleic acid test is 3.03% (4/132 times), and the positive rate of 2019-nCoV nucleic acid test of feces is 9.83% (24/244 times). The positive rate of 2019-nCoV nucleic acid detection in anal swabs is 10.00% (12/120 times).
In this study, it was found that the positive rate of 2019-nCoV nucleic acid in sputum of 132 patients with COVID-19 was higher than that of nasopharyngeal swabs, and viral nucleic acids were also detected in blood and digestive tract (fecal/anal swabs). Simple detection of nasopharyngeal swab 2019-nCoV nucleic acid detection positive rate is not high, multi-sample 2019-nCoV nucleic acid detection can improve the accuracy, reduce the false negative rate, better guide clinical treatment and evaluate the therapeutic effect.
Wu J
，Liu J
，Li S
，Peng Z
，Xiao Z
，Wang X
，Yan R
，Luo J
... -
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Evolution of severe acute respiratory syndrome coronavirus 2 RNA test results in a patient with fatal coronavirus disease 2019: a case report.
A 65-year-old man was hospitalized owing to fever (38.6 °C) and dry cough since 4 days. He visited Wuhan 8 days ago. At admission, nasopharyngeal swab samples were taken, and polymerase chain reaction analysis confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA positivity. On day 9, after admission, the chest computed tomography scan showed diffuse ground-glass shadows in the patient's bilateral lungs. On day 11, his respiratory symptoms worsened. Subsequently, type I respiratory failure was diagnosed, coinciding with kidney injury, and subsequently, type II respiratory failure occurred, coupled with multiorgan failure including the heart and liver. However, the patient's constitution worsened although SARS-CoV-2 tests were negative since day 13. He died on day 21. Lung biopsy showed areas of diffuse alveolar damage, characterized by extensive acute alveolitis with numerous intra-alveolar neutrophil, lymphocyte, and macrophage infiltrations. Microthrombi were seen in the dilated pulmonary capillaries. Immunohistochemistry staining for SARS-CoV-2 N protein was negative. Taken together, the patient died of multiorgan failure although the SARS-CoV-2 infection was cleared already, implicating that for disease worsening, no active SARS-CoV-2 infection is required.
Shao C
，Liu H
，Meng L
，Sun L
，Wang Y
，Yue Z
，Kong H
，Li H
，Weng H
，Lv F
，Jin R
... -
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The implications of preliminary screening and diagnosis: Clinical characteristics of 33 mild patients with SARS-CoV-2 infection in Hunan, China.
In December 2019, coronavirus Disease 2019 (COVID-19) occurred in Wuhan, Hubei Province, China. The disease has rapidly spread from Wuhan to other regions.
To describe the clinical manifestations and epidemiological characteristics of patients with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection in Hunan Province in 2020.
From January 19 to February 7, 2020, 33 patients with positive in nucleic acid test of pharyngeal swab were retrospectively collected and analyzed.
There are 33 COVID-19 patients (16 male, 17 female), and the median age was 46 years. Nineteen patients (48 %) were associated with a family cluster outbreak. Seventeen patients (52 %) had traveled or lived in Hubei Province. These patients are early mild cases, most common symptoms are fever [23 (70 %)] and cough [13 (39 %)]. Most patients' white blood cell counts are normal, while they manifest as significant reduction in lymphocytes [17/28 (61 %)]. The levels of c-reactive protein and erythrocyte sedimentation rate suggest a typical viral infection. Procalcitonin did not increase and D-dimer increased slightly. Lactate dehydrogenase (LDH) levels have elevated in most patients. CT images of these patients showed bilateral multiple plaques or nodular ground-glass opacities (68.4 %). Fecal nucleic acid results were positive in eight COVID-19 patients accompanied with diarrhea. Tear nucleic acid results were negative in six COVID-19 patients. And four asymptomatic patients were infected with SARS-CoV-2.
The clinical symptoms, laboratory results and imaging reports of patients with COVID-19 in Hunan area are significantly different from those in Wuhan area. For non-Wuhan epidemic areas, more attention should be paid to nucleic acid test results of throat swabs and stools, and it is not easily to diagnose based on clinical symptoms and CT results. Reduced whole blood lymph count can be used as an adjuvant diagnosis of early SARS-CoV-2 infection. Attention should be paid to asymptomatic carriers, which is of great significance for the control of the global epidemic.
Yin S
，Peng Y
，Ren Y
，Hu M
，Tang L
，Xiang Z
，Li X
，Wang M
，Wang W
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