SARS-CoV-2 and indoor/outdoor air samples: a methodological approach to have consistent and comparable results

Robotto, Angelo; Quaglino, Paola; Lembo, David; Morello, Marcello; Brizio, Enrico; Bardi, Luisella; Civra, Andrea

doi:10.1016/j.envres.2021.110847

Cited by 36 publications

(40 citation statements)

References 32 publications

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“…Among the described bioaerosol sampling technologies, the most suitable should be chosen to match the following minimal requirements, defined also in a previous study produced by our research group ( Robotto et al, 2021 ): Large volumes of air should be sampled in consideration of the expected dilution in environmental media; High bioaerosol capture efficiency, for fractions around or smaller than 1 μm; Preservation of sample infectivity, to allow viral replication in vitro on susceptible cell cultures; Temperatures should be not hostile to the pathogen throughout the sampling process and the sample transport and manipulation; Low degradation or re-aerosolization, bounce, inlet and wall losses in samplers; Standardized procedures and methods for sampling airborne viruses and enable measurement of the detection limit of the measurement should be established; Use of optimal media for suspension or collection; Sample pre-treatment should be optimized (elution from filters, concentration of transport medium, RNA extraction). …”

Section: Introductionmentioning

confidence: 99%

“…Therefore, a conceptual approach like the one described by Robotto et al (2021) should be developed to allow the choice of suitable collection materials, sampling duration, transport medium and sample pre-treatments with a reliable and reproducible plan. Recovery tests represent a necessary step to validate an analytical method, assuring the right quality to environmental sampling and analysis according to ISO/IEC 17025 standard.…”

Section: Introductionmentioning

confidence: 99%

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SARS-CoV-2 airborne transmission: A validated sampling and analytical method

Robotto

Civra

Quaglino

et al. 2021

Environmental Research

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The airborne transmission path for SARS-CoV-2 is of primary scientific and health-related interest as it could actually involve management, accessibility, use and functionality of many activities, including hospitals), schools, workplaces, factories, transport, sport venues and outdoor environment. It is necessary to develop a sampling and analytical method for virus-laden bioaerosol that could be considered reliable and validated according to ISO/IEC 17025 requirements. The present paper defines sample pretreatments aiming at recover SARS-CoV-2 from glass-fiber and PTFE filters employed by low and high-volume air samplers. Recovery test results focused on the sample concentration step carried out by means of ultracentrifugation are reported as well. Human coronavirus strain OC43 (a surrogate β-coronavirus with the same SARS-CoV-2 particle structure) was used to validate each step of the recovery tests. We found that the elution efficiency of coronavirus OC43 from glass-fiber and quartz filters could be strongly enhanced by using an elution buffer containing up to 40% of fetal calf serum. Moreover, the recovery from PTFE filters is much higher and easier than from glass-fiber filters: for glass-fiber filters a 3 h-shaking phase, followed by a 30 s-vortexing step, are necessary to elute viral infective particles; for PTFE, 60 min-shaking is enough. The effect of suction time on filters could be resumed as follows: sampling durations up to 20 min at a flow rate of 500 L/min do not affect recovery efficiencies from 10 cm glass-fiber filters, whereas the recovery efficiency of infectious virions from 4.7 cm PTFE filters decreases of a factor 2 after 3 h of sampling at a flow rate of 20 L/min. The recovery efficiency of ultracentrifugation turns out to be around 57%. The effect of storage temperature of filters immersed in a transport medium on coronavirus infectivity is assessed as well. Based on the sampling techniques and the analytical methods developed as described in the present study, many field tests were carried out reporting virus concentrations up to 50 genomic copies per cubic meter of air in domestic environment with poor ventilation condition, whereas in hospital wards the detectable concentrations of SARS-CoV-2 were generally lower than 10 genomic copies per cubic meter of air.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

SARS-CoV-2 airborne transmission: A validated sampling and analytical method

Robotto

Civra

Quaglino

et al. 2021

Environmental Research

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“…The levels of community transmission during the human outbreak of COVID-19 have been assessed by detection of the coronavirus in wastewater [9,39]. Inappropriate management or leaks from sewage facilities can produce the release of wastewater to surface water bodies [40] converting this type of event into a potential source of infection.…”

Section: Discussionmentioning

confidence: 99%

First Description of Natural SARS-CoV-2 Infection in Two Wild American Minks (<em>Neovison vison</em>)

Aguiló-Gisbert¹,

Padilla-Blanco²,

Lizana³

et al. 2021

Preprint

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of COVID-19 , is considered a pathogen with animal origin, mainly transmitted human to human. It has been experimentally and naturally demonstrated that several animals can be infected by SARS-CoV-2. There are strong evidences that minks are highly susceptible to SARS-CoV-2 infection, since several cases of human to mink infection have been reported, and it has been suggested mink to human infection exists, which so far it is the most reliable example of a zoonotic event of COVID-19 . However, all these cases reported are form mink farms, with the exception of one case in the USA in which the virus was detected in a mink located in the wild, but it was demonstrated that the animal was infected on a fur farm. In the present work, we have detected SARS-CoV-2 RNA in two wild American minks (Neovison vison) in Valencian Community (Eastern Spain) during invasive species trapping campaigns. The animals were trapped from areas known for harbouring self-sustained populations, far away from the nearest fur farm. SARS-CoV-2 RNA was detected in mesenteric lymph nodes samples by RT-PCR. A partial region of the Spike protein gene was amplified and sequence obtaining a 397 nt size sequence. Phylogenetic analysis shown that both sequences were identical to the consensus variant SARS CoV-2 sequence (from Wuhan). This research describes the first infection report of a true wild American mink not related to infected fur farms or direct contact with humans, which is believed to be the first example of wild animals in which SARS-CoV-2 has been detected.

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“…The source of these viral particles can range from the hospital roof to the ground level, and areas near air intakes surrounding the hospital. The transport of viral particles between regions diminishes air quality and presents a serious risk to anyone within or surrounding the hospital facility, further strengthening the COVID-19 pandemic ( Robotto et al, 2021 ). Ultrafine particles which contain the SARS-CoV-2 virus are easily suspended in the air and have the propensity to travel great distances due to their aerodynamic diameters ≤ 10 μm (≤ PM10).…”

Section: Introductionmentioning

confidence: 99%