Ongoing disease surveillance is a critical tool to mitigate viral outbreaks, especially during a pandemic. Environmental monitoring has significant promise even following widespread vaccination among high-risk populations. The goal of this work is to demonstrate molecular severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) monitoring in bulk floor dust and related samples as a proof of concept of a noninvasive environmental surveillance methodology for coronavirus disease 2019 (COVID-19) and potentially other viral diseases. Surface swab, passive sampler, and bulk floor dust samples were collected from the rooms of individuals positive for COVID-19, and SARS-CoV-2 was measured with quantitative reverse transcription-PCR (RT-qPCR) and two digital PCR (dPCR) methods. Bulk dust samples had a geometric mean concentration of 163 copies/mg of dust and ranged from nondetects to 23,049 copies/mg of dust detected using droplet digital PCR (ddPCR). An average of 89% of bulk dust samples were positive for the virus by the detection methods compared to 55% of surface swabs and fewer on the passive sampler (19% carpet, 29% polystyrene). In bulk dust, SARS-CoV-2 was detected in 76%, 93%, and 97% of samples measured by qPCR, chip-based dPCR, and droplet dPCR, respectively. Detectable viral RNA in the bulk vacuum bags did not measurably decay over 4 weeks, despite the application of a disinfectant before room cleaning. Future monitoring efforts should further evaluate RNA persistence and heterogeneity in dust. This study did not measure virus infectivity in dust or potential transmission associated with dust. Overall, this work demonstrates that bulk floor dust is a potentially useful matrix for long-term monitoring of viral disease in high-risk populations and buildings. IMPORTANCE Environmental surveillance to assess pathogen presence within a community is proving to be a critical tool to protect public health, and it is especially relevant during the ongoing COVID-19 pandemic. Importantly, environmental surveillance tools also allow for the detection of asymptomatic disease carriers and for routine monitoring of a large number of people as has been shown for SARS-CoV-2 wastewater monitoring. However, additional monitoring techniques are needed to screen for outbreaks in high-risk settings such as congregate care facilities. Here, we demonstrate that SARS-CoV-2 can be detected in bulk floor dust collected from rooms housing infected individuals. This analysis suggests that dust may be a useful and efficient matrix for routine surveillance of viral disease.

BackgroundFour sampling techniques commonly are used for antemortem identification of pathogens from cattle with bovine respiratory disease (BRD): the nasal swab (NS), guarded nasopharyngeal swab (NPS), bronchoalveolar lavage (BAL), and transtracheal wash (TTW). Agreement among these methods has not been well characterized.ObjectiveTo evaluate agreement among TTW and NS, NPS, or BAL for identification of viral and bacterial pathogens in dairy calves with BRD.AnimalsOne hundred dairy calves with naturally acquired BRD.MethodsCalves were sampled by all 4 methods. Viral agents were identified by real‐time RT‐PCR, bacteria were identified by aerobic culture, and Mycoplasma bovis (M. bovis) isolates were speciated by PCR. Agreement among TTW and NS, NPS, or BAL was evaluated by calculating the kappa statistic and percent positive agreement. McNemar's exact test was used to compare the proportions of positive results.ResultsAgreement among TTW and NS, TTW and NPS, and TTW and BAL, was very good for identification of P. multocida, M. haemolytica, and M. bovis. For bovine respiratory syncytial virus (BRSV), agreement with TTW was moderate for NS, good for NPS, and very good for BAL. For bovine coronavirus (BCV), agreement with TTW was moderate for NS and NPS, and good for BAL. McNemar's test was significant only for BCV, indicating that for this pathogen the proportion of positive results from NS and NPS could not be considered comparable to TTW.Conclusions and Clinical ImportanceThis study provides guidance for veterinarians selecting diagnostic tests for antemortem identification of pathogens associated with BRD.

Carpet and rugs currently represent about half of the United States flooring market and offer many benefits as a flooring type. How carpets influence our exposure to both microorganisms and chemicals in indoor environments has important health implications but is not well understood. The goal of this manuscript is to consolidate what is known about how carpet impacts indoor chemistry and microbiology, as well as to identify the important research gaps that remain. After describing the current use of carpet indoors, questions focus on five specific areas: 1) indoor chemistry, 2) indoor microbiology, 3) resuspension and exposure, 4) current practices and future needs, and 5) sustainability. Overall, it is clear that carpet can influence our exposures to particles and volatile compounds in the indoor environment by acting as a direct source, as a reservoir of environmental contaminants, and as a surface supporting chemical and biological transformations. However, the health implications of these processes are not well known, nor how cleaning practices could be optimized to minimize potential negative impacts. Current standards and recommendations focus largely on carpets as a primary source of chemicals and on limiting moisture that would support microbial growth. Future research should consider enhancing knowledge related to the impact of carpet in the indoor environment and how we might improve the design and maintenance of this common material to reduce our exposure to harmful contaminants while retaining the benefits to consumers.

RATIONALE: Respiratory diseases, including asthma, cause significant morbidity and mortality worldwide and may result from the interplay between endogenous and exogenous factors. Staphylococcus aureus (SA), an opportunistic pathogen, and eosinophilia, a marker of inflammation, are both associated with allergic diseases and may be two such factors. Therefore, we hypothesized that elevated eosinophils could impact the relationship between SA and chronic respiratory diseases. METHODS: SA nasal colonization, inflammatory markers, and respiratory outcome data were obtained from the National Health and Nutrition Examination Survey 2001-04. Relationships between SA and respiratory outcomes (e.g. asthma, wheeze, and exacerbation-related morbidities) were evaluated via logistic regression, controlling for demographics, household smoking, recent respiratory illness, healthcare visits, and poverty-income ratio. Eosinophilia (>300cells/mL) was explored as a confounder and modifier of the SA-respiratory relationship. RESULTS: Eosinophils modified the relationship between SA and 8 of 9 respiratory outcomes. For example, asthma prevalence among those with both SA and eosinophilia was 15.7%; compared to neither factor (6.5%), SA-only (6.5%), or eosinophilia-only (11.1%), p50.03 for interaction. Similarly, SA was associated with 25% higher odds of taking medication for wheezing among those with eosinophilia [OR 1.25, 95% Confidence Interval (CI): 0.77, 2.03], but only 8% among those without [OR 1.08, 95%CI: 0.71, 1.62], p50.04 for interaction. CONCLUSIONS: SA was associated with higher odds of respiratory outcomes among US residents with eosinophilia, suggesting the importance of an allergic immune profile to the SA-respiratory relationship. Future longitudinal studies should evaluate if SA plays a causal role in respiratory disease among those with allergic disease.

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