Assessing the Impact of Covid-19 on Human Activities in the Greater Toronto Area by Nighttime Light Images and Active Covid-19 Cases

This paper explores the effect of COVID-19 outbreaks on human activity through nighttime light images of Greater Toronto Area (GTA), Canada. The methods used in this paper include image preprocessing, image classification, and spatial analysis. By using the nighttime light radiance data from VIIRS/NPP data products and COVID-19 cases and comparing this data from the pre-pandemic year, the impact of COVID-19 was analyzed. The result shows that during the pandemic year the monthly average nighttime light radiance has decreased about 4.3-5.0% compared to the pre-pandemic year. The classification results shows that the average percentage of changes in residential areas, public facilities, and commercial areas are 0.3%, -0.7%, and -1.2%, respectively of each corresponding month. Meanwhile, the spatial analysis results show population distribution patterns in GTA during the pandemic year. Overall, the nighttime lights (NTL) images can be used for a preliminary understanding of how COVID-19 affected human activities and is corroborated with other forms data collection used for the pandemic analysis.

A real-time monitoring platform of colorimetric LAMP for developing rapid visual detection kits of SARS-CoV-2

Visual detection of nucleic acids is important to diagnose the serious acute infectious diseases such as coronavirus disease 2019 (COVID-19). During this pandemic, reliable visual detection kits have been in high demand for screening and prevention of the virus. While developing these visual detection kits, a real-time monitoring platform is usually applied to study the amplification and detection processes of nucleic acids and optimize the detecting conditions. Herein, we developed a real-time monitoring platform of colorimetric loop-mediated isothermal amplification (LAMP) to investigate the amplification and detection processes of nucleic acids. Using this platform, we could obtain the real-time amplification curves, and optimize the reaction temperature, color change, and detection time. Based on the optimized conditions, a visual detection kit for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was successfully developed with a sensitivity of 102 copies µL−1 in 12 min. This real-time monitoring platform has advantages of simple construction, steady performance, high sensitivity, and outstanding anti-pollution capability, and could replace the traditional colorimetric methods by photographing and reading values. This platform would accelerate the development of visual detection kits for colorimetric LAMP, help to explore the amplification and transcription of nucleic acids, and provide support for the prevention of emerging biological threats. © 2023

TROPISM OF SARS-COV-2 FOR BARRETT'S ESOPHAGUS MAY INCREASE SUSCEPTIBILITY TO DEVELOPING COVID-19

Background and Aims: In addition to pulmonary and thrombotic sequalae, gastrointestinal (GI) manifestations of COVID-19 are common. Although enterocytes express ACE2 and TMPRSS2, the proteins that determine SARS-CoV-2 tropism, prior studies have suggested that the virus is inactivated by gastric acid and other luminal fluids as it transits the gastrointestinal tract. However, we reason here that individuals with intestinal metaplasia of the esophagus and stomach might have ectopic, proximal SARS-CoV-2 receptor expression that would predispose them to infection from ingested oral secretions or respiratory sputum. Methods: Histology, immunohistochemistry, and immunofluorescence were performed on human tissue and organoid cultures derived from biopsied human Barrett’s esophagus. Organoid cultures were infected with a chimeric virus expressing the SARS-CoV-2 spike protein (rVSV-eGFP-SARS-CoV-2). Both fixed and live cells were imaged by light, epifluorescence, and live confocal microscopy. Results: Unlike normal esophagus and stomach, Barrett’s esophagus and gastric intestinal metaplasia both strongly express apical ACE2 and TMPRSS2 at the protein level. Organoids derived from Barrett’s esophagus are readily infected by the chimeric rVSV-eGFP-SARSCoV- 2 virus as demonstrated by the GFP fluorescence observed in both epifluorescence as well as three-dimensional, time-lapse confocal imaging of live infected organoids. We observed that fluorescence persisted for greater than 2 weeks in culture suggesting ongoing viral infection and intestinal identity correlated with increased viral entry. Conclusions: SARS-CoV-2 has a previously undescribed tropism for Barrett’s esophagus and gastric intestinal metaplasia, placing these individuals at higher risk of infection via the orogastric route.

[Clinical analysis of liver chemistries in children and adolescent with 2019-nCoV infection].

Objective: To describe the clinical features of liver involvement in children and adolescent with 2019-nCoV infection. Methods: The clinical data of 77 hospitalized cases admitted to the Children's Hospital of Fudan University were collected from January 19 to November 28, 2020. The characteristics and risk factors of abnormal liver chemistries in children with laboratory-confirmed 2019-nCoV infection were analyzed. Results: Of the 77 cases, 44 were male (57.1%) and 33 were female (42.9%), with a median age of 10 years. 27(35.1%) were asymptomatic, 28(36.4%) had mild illness, 22(28.6%)had non-severe pneumonia. Hydroxychloroquine was used in 7 cases. Of the 75 children without underlying diseases, alanine aminotransferase was elevated in 1 case (1.5%, during hydroxychloroquine therapy), aspartate aminotransferase was elevated in 7 cases (10.3%), alkaline phosphatase was elevated in 7 cases (28%), and total bilirubin, direct bilirubin, albumin, international normalized ratio were in normal range. There was no statistical difference between the pneumonia group and the non-pneumonia group in term of liver chemistries (P > 0.05), same as between the elevated erythrocyte sedimentation rate group and the normal group. There was no aggravation of liver injury in the child with biliary atresia. The child with epilepsy showed no abnormal liver chemistries after infection. Conclusion: Children with 2019-nCoV infection had mild clinical symptoms with few cases of liver injury. The abnormal liver chemistries in children with COVID-19 infection may be related to the underlying disease and the use of antiviral drugs.

Intervention Effect Analysis on Traffic Safety in Urban Core Areas under Influence of COVID-19

The traffic safety characteristics were changed in urban core areas under the influence of COVID-19. In this paper, a one-dimensional time series was constructed based on the data of traffic accident reception and handling. Through the descriptive analysis, the time distribution characteristics of traffic accident under COVID-19 epidemic was studied. In view of the non-stationary characteristics of traffic accident sequence, wavelet decomposition technology was used to extract the structural mutation point of the sequence under the COVID-19 controlling policies, which excluded the influence of the Spring Festival holiday. With the supported vector machine(SVM) method, an intervention model was established to evaluate the impact of COVID-19 epidemic prevention policies on traffic accidents. The research results show that the rigor traffic prevention policies have reduced the daily traffic accident rate by 12.23 on average, and then it attenuates at a rate of 68.7%, and then to recover at a rate of 30.9%, which lasts until the implementation of the policy of resuming work and production;and the relatively lenient traffic control policies stabilizes the reduction of daily accident rate at 11.707 on average. Copyright © 2020 by Science Press.

Renal dysfunction, COVID-19 infection, and mortality

Background: Critically ill patients with the SARS-CoV-2 virus (COVID-19) infection have diverse clinical manifestations including renal dysfunction which can determine their short-term outcomes. We assess if renal dysfunction on day one of hospital admission is associated with increased mortality risk of patients with severe COVID-19 infection. Methods: We conducted a retrospective review of records of patients with severe COVID-19 infection admitted to the Intensive Care Unit between March 4 and April 11, 2020. Patients were divided into two groups based on serum creatinine level on day one of hospital admission. Group 1 included patients with normal serum creatinine (SCr) 1.10 mg/dl while group 2 included patients with high SCr > 1.10 mg/dl. The primary outcome was mortality. Secondary outcomes were the need for renal replacement therapy (RRT), duration of RRT, development of adult respiratory distress syndrome (ARDS) and need for mechanical ventilation. Comparisons between groups were done using Mann-Whitney U-tests for continuous variables and chi-square tests for categorical variables. Mortality was evaluated with a Kaplan-Meier Survival Analysis. Results: A total of 47 patients were included: 27 in group 1 and 20 in group 2. Patients in group 2 compared to group 1 were older (67 vs. 56, p=0.04), more frequently African Americans (11% vs 45%, p=0.02), hypertensives (80% vs 52%, p=0.05) with chronic kidney disease (25% vs 0%, p=0.01), without significant differences sex, diabetes mellitus, smoking status or use of renin-angiotensin antagonists. 8 patients in group 2 and 3 patients in group 1 died, with significant difference in cumulative survival (Figure 1). Need for RRT (55% vs 41%, p=0.33), duration of RRT (6 vs 3 days, p=0.08), development of ARDS (85% vs 81%, p=0.75) and need for mechanical ventilation (65% vs 61%, p=0.89) were not significantly different between groups 2 and 1. Conclusions: The presence of renal dysfunction on the day of hospital admission is associated with increased hospital mortality in patients with severe COVID-19 infection.