Swabbing the Urban Environment - A Pipeline for Sampling and Detection of SARS-CoV-2 From Environmental Reservoirs

Abstract

To control community transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the 2020 global pandemic, most countries implemented strategies based on direct human testing, face covering, and surface disinfection.Under the assumption that the main route of transmission includes aerosols and respiratory droplets, efforts to detect SARS-CoV-2 in fomites have focused on locations suspected of high prevalence (e.g., hospital wards, cruise ships, and mass transportation systems). To investigate the presence of SARS-CoV-2 on surfaces in the urban environment that are rarely cleaned and seldomly disinfected, 350 citizens were enlisted from the greater San Diego County. In total, these citizen scientists collected 4,080 samples. An online platform was developed to monitor sampling kit delivery and pickup, as well as to collect sample data. The sampling kits were mostly built from supplies available in pandemic-stressed stores. Samples were processed using reagents that were easy to access despite the recurrent supply shortage. The methods used were highly sensitive and resistant to inhibitors that are commonly present in environmental samples. The proposed experimental design and processing methods were successful at engaging numerous citizen scientists who effectively gathered samples from diverse surface areas. The workflow and methods described here are relevant to survey the urban environment for other viruses, which are of public health concern and pose a threat for future pandemics.

Presence of SARS-CoV-2 RNA on Surfaces of Public Places and a Transportation System Located in a Densely Populated Urban Area in South America

“…It is important to consider that the present study had some limitations. Firstly, the limit of detection for the technique we employed is 10 viral RNA copies [8]. Therefore, if there were less than 10 viral RNA copies on a given surface, the virus was not detected, resulting in a false negative.…”

“…The primary route of viral transmission is direct person-to-person contact, Viruses 2022, 14, 19 2 of 8 through respiratory droplets. Additionally, alternative routes of transmission have been proposed via indirect contact through fomites and SARS-CoV-2 positive surfaces, as large amounts of SARS-CoV-2 can cause some virus to remain viable on dry surfaces and in aerosols for long periods of time [1,[6][7][8].…”