Bioaerosol Sampling for Respiratory Viruses in Singapore’s Mass Rapid Transit Network

Abstract

As a leading global city with a high population density, Singapore is at risk for the introduction of novel biological threats. This risk has been recently reinforced by human epidemics in Singapore of SARS coronavirus, 2009 pandemic H1N1 influenza A virus, and enterovirus 71. Other major threats to Singapore include MERS-coronavirus and various avian and swine influenza viruses. The ability to quickly identify and robustly track such threats to initiate an early emergency response remains a significant challenge. In an effort to enhance respiratory virus surveillance in Singapore, our team conducted a pilot study employing a noninvasive bioaerosol sampling method to detect respiratory viruses in Singapore’s Mass Rapid Transit (MRT) network. Over a period of 52 weeks, 89 aerosol samples were collected during peak MRT ridership hours. Nine (10%) tested positive for adenovirus, four (4.5%) tested positive for respiratory syncytial virus type A, and one (1%) tested positive for influenza A virus using real-time RT-PCR/PCR. To our knowledge, this is the first time molecular evidence for any infectious respiratory agent has been collected from Singapore’s MRT. Our pilot study data support the possibility of employing bioaerosol samplers in crowded public spaces to noninvasively monitor for respiratory viruses circulating in communities.

Airborne Influenza A Virus Exposure in an Elementary School

“…Although airborne influenza virus has been detected in select indoor settings 37,38,44,[61][62][63][64][65] , the ability to consistently detect the virus in the airshed remains limited in environments featuring low IAV densities. We now have the first molecular evidence of airborne IAV in an elementary school, during a portion of the influenza season when students were exposed for appropriate durations to densities of influenza-laden particles that could facilitate infection.…”

First sequence of influenza D virus identified in poultry farm bioaerosols in Sarawak, Malaysia

“…From June 3 to August 3, 2018, our study team collected 28 bioaerosol samples from five poultry farms across the Sibu Division of Sarawak, Malaysia. Bioaerosol sampling was conducted using the National Institute of Occupational Safety and Health's (NIOSH, Morgantown, West Virginia, USA) model BC 251 two-stage bioaerosol sampler calibrated at a rate of 3.5 L/min [14][15][16]. At the poultry farm, NIOSH samplers were fixed approximately 1 m above the ground on a stationary tripod, set-up near or inside the holding pens of the chickens or ducks for a 1.5-h period.…”

“…Viral RNA extracts were analyzed with a real-time polymerase chain reaction (qPCR) for detection of influenza D virus [15] using Superscript R III Platinum One-…”

Bioaerosols and Transmission, a Diverse and Growing Community of Practice

“…Progress in the field has been stimulated by advances in other areas which have been applied to the study of infectious bioaerosols. These include: (a) enhanced detection by molecular methods, principally real-time and quantitative PCR, nextgeneration sequencing, metagenomics, and biosensors (25)(26)(27)(28)(29)(30), and (b) establishment of both conventional and novel infrastructure, such as small and large-scale wind tunnels, biocontained rotating drums for aging aerosols, and field-ready aerosol samplers (31)(32)(33). Ongoing research has also facilitated the development and dissemination of procedures and protocols for experimental work, including artificial aerosols, as well as animal models of transmission including the ferret model for influenza virus transmission and macaque model for Ebola virus transmission (34,35).…”