Detection of SARS-CoV-2 in exhaled air using non-invasive embedded strips in masks.

BACKGROUND: SARS-CoV-2 emerged in 2019 and resulted in a pandemic causing millions of infections worldwide. Gold-standard for SARS-CoV-2 detection uses quantitative RT-qPCR on respiratory secretions to detect viral RNA (vRNA). Acquiring these samples is invasive, can be painful for those with xerostomia and other health conditions, and sample quality can vary greatly. Frequently only symptomatic individuals are tested even though asymptomatic individuals can have comparable viral loads and efficiently transmit virus. METHODS: We utilized a non-invasive approach to detect SARS-CoV-2 in individuals, using polyvinyl alcohol (PVA) strips embedded in KN95 masks. PVA strips were tested for SARS-CoV-2 vRNA via qRT-PCR and infectious virus. RESULTS: We show efficient recovery of vRNA and infectious virus from virus-spiked PVA with detection limits comparable to nasal swab samples. In infected individuals, we detect both human and SARS-CoV-2 RNA on PVA strips, however, these levels are not correlated with length of time mask was worn, number of times coughed or sneezed, or level of virus in nasal swab samples. We successfully cultured and deep-sequenced PVA-associated virus. CONCLUSIONS: These results demonstrate the feasibility of using PVA-embedded masks as a non-invasive platform for detecting SARS-CoV-2 in exhaled air in COVID-positive individuals regardless of symptom status.

Restoration of high zinc and lead tailings with municipal biosolids and lime: a field study.

A field study was conducted to test the ability of biosolids (BS) and different types of lime to increase soil pH, neutralize subsoil acidity, and restore a vegetative cover to alluvial mine tailings in Leadville, CO. The tailings had soil pH of 5.2 and total Cd, Pb, and Zn of 75+/-20, 2600+/-1100, and 6700+/-1900 mg kg(-1). Types of lime included agricultural lime (AL), sugar beet lime (SBL), and lime kiln dust (LKD) applied at 224 Mg ha(-1) calcium carbonate equivalent. Plots were established in 2000 and monitored intermittently through 2007. All amendments increased pH in surface and subsurface depths, with LKD, LKD+BS, and SBL+BS being the most effective. Amendments also reduced 0.01 mol L(-1) Ca(NO3)2 extractable Zn and Cd compared to the control. Plant growth was sparse on all treatments with limited yield for three of four harvests. Poor growth may have been related to elevated electrical conductivity (EC). All amendments except LKD alone (5.79 dS m(-1)) increased EC compared to the control treatment (5.28 dS m(-1)). Electrical conductivity was highest in 2002 which had the lowest summer rainfall. In 2005 EC in all treatments except the SBL+BS was similar in the surface soil. Aboveground plant tissue concentrations of Zn and Cd were also elevated. Limited precipitation and high electrical conductivity may be responsible for poor plant growth. Higher rainfall for the last sampling period resulted in significant growth in the LKD+BS, SBL+BS, and LKD alone treatments.

Revegetation of high zinc and lead tailings with municipal biosolids and lime: greenhouse study.

Acidic (pH 4.1) and high Cd, Pb, and Zn mine tailings (mean +/- SD: 17 +/- 0.4, 3800 +/- 100, and 3500 +/- 100 mg kg(-1), respectively) from an alluvial tailings deposit in Leadville, Colorado were amended with municipal biosolids (BS) (224 Mg ha(-1)) and different types of lime (calcium carbonate equivalent of 224 Mg ha(-1) CaCO3) in a greenhouse column study to test the ability of the amendments to neutralize surface and subsoil acidity and restore plant growth. The types of lime included coarse, agricultural, and fine-textured lime (CL, AL, and FL), sugar beet lime (SBL), and lime kiln dust (LK). The FL was also added alone. All treatments increased bulk pH in the amended horizon in comparison to the control, with the most significant increases observed in the FL, SBL+BS, and LK+BS treatments (7.33, 7.34, and 7.63, respectively). All treatments, excluding the FL, increased the pH in the horizon directly below the amended layer, with the most significant increases observed in the SBL+BS and LK+BS treatments (6.01 and 5.41, respectively). Significant decreases in 0.01 M Ca(NO3)2-extractable Zn and Cd were observed in the subsoil for all treatments that included BS, with the largest decrease in the SBL+BS treatment (344 and 3.9 versus 4 and 0.1 mg kg(-1) Zn and Cd, respectively). Plant growth of annual rye (Lolium multiflorum L.) was vigorous in all treatments that included BS with plant Zn, Cd, and Pb concentrations reduced over the control.

Effect of amendment C:N ratio on plant richness, cover and metal content for acidic Pb and Zn mine tailings in Leadville, Colorado.

Biosolids and woody debris were applied with target C:N ratios of 8:1 to 50:1 to phytotoxic, acidic, high metal mine tailings to test the effect of amendment C:N ratio on native plant restoration. Total soil C decreased over time indicating an active microbial community. The 8:1 treatment initially had no growth, the highest plant cover for the final sampling (86.8+/-13.8%) and the lowest number of species (3.33+/-0.4). The greatest number of species was in the 30:1 treatment (5.44+/-0.45). Plant cover increased over time for all treatments from 44.7% in 2001 to 71% in 2005. This response was consistent across all except for the 30:1 treatment, which showed a slight decrease in the final year (65+/-11%). Volunteer species and evidence of animal grazing were observed in all amended plots. Results indicate that a C:N ratio>/=20:1 increased species diversity.

A gastroenteritis outbreak due to norovirus associated with a Colorado hotel.

Describing the system components of norovirus outbreaks is important in understanding how to prevent future outbreaks. Investigation of these components includes environmental, epidemiologic, and laboratory perspectives. This study describes how an investigation from these three perspectives was conducted and the significance of each component in understanding norovirus outbreaks. On May 23, 2000, members of a professional group attending two meetings at a local hotel in Englewood, Colorado, began to complain of gastrointestinal illness. Sixty-nine illnesses were reported among 133 attendees. Eight hotel employees also complained of illness. Staff from the Tri-County Health Department and the Centers for Disease Control and Prevention investigated the outbreak. Three stool specimens collected from ill attendees contained norovirus. While the epidemiologic component did not identify a specific vehicle of transmission, the environmental investigation revealed food-handling practices, food handler perceptions, and hotel policies that may have contributed to disease transmission.

Phosphorus and nitrogen runoff from a forested watershed fertilized with biosolids.

Municipal biosolids are typically not used on the steepest of forested slopes in the U.S. Pacific Northwest. The primary concern in using biosolids on steep slopes is movement of biosolids particles and soluble nutrients to surface waters during runoff events. We examined the pattern and extent of P and N runoff from a perennial stream draining a small, forested 21.4-ha watershed in western Washington before and after biosolids application. In this study, we applied biosolids at a rate of 13.5 Mg ha(-1) (700 kg N ha(-1) and 500 kg P ha(-1)) to 40% of the watershed following nearly 1.5 years of pre-application water sampling and 1.5 years thereafter. There was no evidence of direct runoff of P or N from biosolids into surface water. Elevated surface water discharge did not change the concentration of PO4-P, biologically available phosphorus (BAP), bioavailable particulate phosphorus (BPP), or total P nor did it affect the concentration-discharge relationship. Some instances of total P concentrations exceeding the USEPA surface water standard of 0.1 mg L(-1) were observed following biosolids application. However, total P in 27 Creek was predominately in particulate form and not labile, suggesting that detritus moving into the main creek channel and ephemeral drainage courses may be the principal P source. Ammonium N concentrations in runoff water were consistent before and after biosolids application, ranging from below detection limits (0.01 mg L(-1)) to 0.1 mg L(-1); no concentration-discharge relationship existed. Biosolids application changed the 27 Creek concentration-discharge relationship for NO3(-)-N. Before application, no relationship existed. Beginning nine months after biosolids application, increases in discharge were positively related to increases in NO3(-)-N concentrations. Nitrate concentrations in runoff following biosolids application were approximately 10 times less than the USEPA drinking water standard of 10 mg L(-1).