To investigate how different routes of exposure affected disease development, the scientists exposed hamsters to SARS-CoV-2 via both aerosols and fomites. For aerosol exposure, the scientists used equipment that controlled the size of virus-loaded droplets. For fomite exposure, they placed a dish contaminated with SARS-CoV-2 in the animal cages.
The scientists found that aerosol exposure directly deposited SARS-CoV-2 deep into the lungs, whereas fomite exposure resulted in initial virus replication in the nose. Regardless of exposure route, animals had SARS-CoV-2 replicating in the lungs, but lung damage was more severe in aerosol-exposed animals compared to the fomite group.
A second part of the study compared animal-to-animal transmission of the virus through the air and in contaminated cage environments (fomites). Airborne transmission was markedly more efficient compared to fomite transmission, suggesting that airborne droplets are a key SARS-CoV-2 transmission route. An additional experiment, using air flowing from infected to uninfected animals, supported the finding: Reversing the airflow from uninfected to infected animals greatly reduced transmission efficiency.
The findings support public health guidance focused on interventions to reduce indoor airborne transmission of SARS-CoV-2. These efforts include masking, increasing air filtration and social distancing, as well as handwashing and regular surface disinfection, particularly in clinical settings.
See:
Julia R. Port, Claude Kwe Yinda, Irene Offei Owusu, Myndi Holbrook, Robert Fischer, Trenton Bushmaker, Victoria A. Avanzato, Jonathan E. Schulz, Craig Martens, Neeltje van Doremalen, Chad S. Clancy, Vincent J. Munster. SARS-CoV-2 disease severity and transmission efficiency is increased for airborne compared to fomite exposure in Syrian hamsters. Nature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-25156-8
Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)
Excellent results. Still, I'd like to imagine how can such viruses replicate its structures in the nose? Lung cells are the main target using its biomacbnary for replication. All the best
ReplyDeleteExcellent results. Still, I'd like to imagine how can such viruses replicate its structures in the nose? Lung cells are the main target using its biomacbnary for replication. All the best
ReplyDeleteOdd conclusion. Aerosols are sub micron in size and are best visualised as clouds of smoke around a person, with unpredictable trajectories and lingering in the air for a long time. Masks were introduced based on droplet spread hypothesis (particles larger than 1 micron), with a predictable arc of falling to the ground, hence the social distancing. Hand washing was on the basis of fomite spread. Only ventilation could be argued to be an effective mitigation measure out of the ones listed since we now know aerosol spread is the main driver.
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