Rapid and quantitative detection of respiratory viruses using surface-enhanced Raman spectroscopy and machine learning.

Rapid and sensitive pathogen detection is important for prevention and control of disease. Here, we report a label-free diagnostic platform that combines surface-enhanced Raman scattering (SERS) and machine learning for the rapid and accurate detection of thirteen respiratory virus species including SARS-CoV-2, common human coronaviruses, influenza viruses, and others. Virus detection and measurement have been performed using highly sensitive SiO2 coated silver nanorod array substrates, allowing for detection and identification of their characteristic SERS peaks. Using appropriate spectral processing procedures and machine learning algorithms (MLAs) including support vector machine (SVM), k-nearest neighbor, and random forest, the virus species as well as strains and variants have been differentiated and classified and a differentiation accuracy of >99% has been obtained. Utilizing SVM-based regression, quantitative calibration curves have been constructed to accurately estimate the unknown virus concentrations in buffer and saliva. This study shows that using a combination of SERS, MLA, and regression, it is possible to classify and quantify the virus in saliva, which could aid medical diagnosis and therapeutic intervention.

Analysis of Digestive Endoscopic Results During COVID-19.

OBJECTIVE: This study aims to explore the necessity and safety of digestive endoscopy during the epidemic of coronavirus disease 2019. METHODS: A retrospective cohort study method was used to collect patients' data from the endoscopy center of the Civil Aviation General Hospital of China from February 1 to May 31, 2020, as the observation group. The patients' data of endoscopic diagnosis and treatment during the same period in 2019 were used as a control group, to compare the differences in the number of diagnosis and treatment and the detection rate of gastrointestinal diseases in the two groups. At the same time, patients and related staff were followed up for the situation of new infection. RESULTS: During the epidemic, our endoscopy center conducted a total of 1,808 cases of endoscopic operations and 5,903 cases in the control group. The amount of endoscopic work during the epidemic period was 30.63% in the same period last year. During the epidemic, 26 patients underwent endoscopic mucosal resection (EMR)/endoscopic submucosal dissection (ESD) treatment, 26 patients underwent ERCP, and 18 patients underwent gastrointestinal stent implantation. In the control group, 273 patients underwent EMR/ESD, 17 underwent ERCP, and 16 underwent gastrointestinal stenting. During COVID-19, compared with the same period last year, the detection rates of peptic ulcer, esophageal cancer, gastric cancer, colon cancer, and rectal cancer were significantly higher (χ 2 = 4.482, P = 0.034; χ 2 = 5.223, P = 0.006; χ 2 = 2.329, P = 0.041; χ 2 = 8.755, P = 0.003; and χ 2 = 5.136, P = 0.023). Through telephone follow-up, novel coronavirus nucleic acid detection and blood antibody detection, no patients or medical staff were infected with the novel coronavirus. CONCLUSION: During COVID-19, the number of digestive endoscopic operations decreased significantly compared with the same period last year, but the detection rate of various diseases of the digestive tract increased significantly. On the basis of strict prevention and control, orderly recovery of endoscopic work is essential.