Comparison of heat-inactivated and infectious SARS-CoV-2 across indoor surface materials shows comparable RT-qPCR viral signal intensity and persistence

Environmental monitoring in public spaces can be used to identify surfaces contaminated by persons with COVID-19 and inform appropriate infection mitigation responses. Research groups have reported detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) on surfaces days or weeks after the virus has been deposited, making it difficult to estimate when an infected individual may have shed virus onto a SARS-CoV-2 positive surface, which in turn complicates the process of establishing effective quarantine measures. In this study, we determined that reverse transcription-quantitative polymerase chain reaction (RT-qPCR) detection of viral RNA from heat-inactivated particles experiences minimal decay over seven days of monitoring on eight out of nine surfaces tested. The properties of the studied surfaces result in RT-qPCR signatures that can be segregated into two material categories, rough and smooth, where smooth surfaces have a lower limit of detection. RT-qPCR signal intensity (average quantification cycle (Cq)) can be correlated to surface viral load using only one linear regression model per material category. The same experiment was performed with infectious viral particles on one surface from each category, with essentially identical results. The stability of RT-qPCR viral signal demonstrates the need to clean monitored surfaces after sampling to establish temporal resolution. Additionally, these findings can be used to minimize the number of materials and time points tested and allow for the use of heat-inactivated viral particles when optimizing environmental monitoring methods. ImportanceEnvironmental monitoring is an important tool for public health surveillance, particularly in settings with low rates of diagnostic testing. Time between sampling public environments, such as hospitals or schools, and notifying stakeholders of the results should be minimal, allowing decisions to be made towards containing outbreaks of coronavirus disease 2019 (COVID-19). The Safer At School Early Alert program (SASEA) [1], a large-scale environmental monitoring effort in elementary school and child care settings, has processed > 13,000 surface samples for SARS-CoV-2, detecting viral signals from 574 samples. However, consecutive detection events necessitated the present study to establish appropriate response practices around persistent viral signals on classroom surfaces. Other research groups and clinical labs developing environmental monitoring methods may need to establish their own correlation between RT - qPCR results and viral load, but this work provides evidence justifying simplified experimental designs, like reduced testing materials and the use of heat-inactivated viral particles.

Automated, miniaturized, and scalable screening of healthcare workers, first responders, and students for SARS-CoV-2 in San Diego County

BackgroundSuccessful containment strategies for SARS-CoV-2, the causative virus of the COVID-19 pandemic, have involved widespread population testing that identifies infections early and enables rapid contact tracing. In this study, we developed a rapid and inexpensive RT- qPCR testing pipeline for population-level SARS-CoV-2 detection, and used this pipeline to establish a clinical laboratory dedicated to COVID-19 testing at the University of California San Diego (UCSD) with a processing capacity of 6,000 samples per day and next-day result turnaround times. Methods and findingsUsing this pipeline, we screened 6,786 healthcare workers and first responders, and 21,220 students, faculty, and staff from UCSD. Additionally, we screened 6,031 preschool-grade 12 students and staff from public and private schools across San Diego County that remained fully or partially open for in-person teaching during the pandemic. Between April 17, 2020 and February 5, 2021, participants provided 161,582 nasal swabs that were tested for the presence of SARS-CoV-2. Overall, 752 positive tests were obtained, yielding a test positivity rate of 0.47%. While the presence of symptoms was significantly correlated with higher viral load, most of the COVID-19 positive participants who participated in symptom surveys were asymptomatic at the time of testing. The positivity rate among preschool-grade 12 schools that remained open for in-person teaching was similar to the positivity rate at UCSD and lower than that of San Diego County, with the children in private schools being less likely to test positive than the adults at these schools. ConclusionsMost schools across the United States have been closed for in-person learning for much of the 2020-2021 school year, and their safe reopening is a national priority. However, as there are no vaccines against SARS-CoV-2 currently available to the majority of school-aged children, the traditional strategies of mandatory masking, physical distancing, and repeated viral testing of students and staff remain key components of risk mitigation in these settings. The data presented here suggest that the safety measures and repeated testing actions taken by participating healthcare and educational facilities were effective in preventing outbreaks, and that a similar combination of risk-mitigation strategies and repeated testing may be successfully adopted by other healthcare and educational systems.

Analysis on iodized salt surveillance of Changzhou City in Jiangsu Province during 1996-2007 / 中国地方病学杂志

Objective To explore the qualification and consuming of iodized salt at wholesale and household levels after Salt Iodization.Methods Iodized salt surveillance at wholesale and household levels every year by detecting iodine content.Direct titration method(GB/T 13025.7-1999)was used for salt iodjne detecting and arbitration method was used for Sichuan salt and special salt.Results Five thousand six hundred and seventy five samples of 227 batches from 3 wholesale industries were detected during 1996-2000,batch qualification rate was 60.79%(138/227)and iodized salt qualification rate was 61.83%(3509/5675).During 2001-2007,2556 samples of 252 batches from wholesale levels were detected.The batch qualification rate and iodized salt qualification rate were 1 00%(252/252)and 99.88%(2553/2556),respectively.At household level.1583 samples from 236 villages were detected during 1996-2000.Iodized salt qualification rate was 74.24%(1 170/1576)and consuming rate of qualified iodized salt was 73.91%(1 170/1583)and iodine median was 45.14 mg/kg.During 2001-2007,13 140 samples from 1656 villages were detected.Iodized salt qualification rate,consuming rate 0f qualified iodized salt and iodine median were 98.03%(12 830/13 088),97.64%(12 830/13 140)and 30.13 mg/kg,respectively. The most difference of iodine content was 3.46 mg/kg in 3 wholesale industries.At household level there was a 4.95%reduction in comparison with at wholesale level.Conclusions Salt iodization level and edible iodine salt reach the national requirements of iodine deficiency control from the starting stage.The quality 0f iodized saIt at household level related to the exclusive wholesale industry and loss phenomenon maybe existed when salt was sold from wholesale industries to residents.

Reporter gene assay for detection of shellfish toxins / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To explore the potential reporter gene assay for the detection of sodium channel-specific toxins in shellfish as an alternative for screening harmful algal bloom (HAB) toxins, considering the fact that the existing methods including HPLC and bioassay are inappropriate for identifying HAB toxins which poses a serious problem on human health and shellfish industry.</p><p><b>METHODS</b>A reporter plasmid pEGFP-c-fos containing c-fos promoter and EGFP was constructed and transfected into T24 cells using LipofectAMINE 2000. Positive transfectants were screened by G418 to produce a pEGFP-c-fos-T24 cell line. After addition of increasing neurotoxic shellfish poison (NSP) or GTX2,3, primary components of paralytic shellfish poison (PSP), changes in expression of EGFP in the cell line were observed under a laser scanning confocal microscope and quantified with Image-pro Plus software.</p><p><b>RESULTS</b>Dose-dependent changes in the intensity of green fluorescence were observed for NSP in a range from 0 to 10 ng/mL and for GTX2,3 from 0 to 16 ng/mL.</p><p><b>CONCLUSION</b>pEGFP-c-fos-T24 can be applied in detecting HAB toxins, and cell-based assay can be used as an alternative for screening sodium channel-specific HAB toxins.</p>

Impact evaluation of universal salt iodization on spectrum of thyroid diseases in Changzhou area, Jiangsu, China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the impact of universal salt iodization using monitoring data on correctional status of iodine deficiency and hospitalized thyroid diseases.</p><p><b>METHODS</b>Retrospective survey was conducted to collect medical records of hospitalized thyroid disease cases. Routine monitoring data on population iodine nutrition status and goiter prevalence were analyzed.</p><p><b>RESULTS</b>The coverage of adequately iodized salt was consistently above 95%. Hospitalization rate of thyroid diseases rose steadily, and peaked at 54.5 per 100,000. The proportion of hospitalized thyroid disease among hospitalized diseases also rose with female and those aged above 40 years old mostly affected. The proportion of hospitalized hyperthyroidism among total hospitalized thyroid disease rose from 13.6% to 34.7%.</p><p><b>CONCLUSIONS</b>Universal salt iodization might eliminate iodine deficiency while other impact still exists. However, the benefits of universal salt iodization should be far overweight the adverse effects.</p>