Mary Wilson
Well-known member
Since the pandemic’s beginning, scientists have argued over how respiratory viruses can spread. Now an experiment with guinea pigs and influenza is adding a new wrinkle.
08.19.2020 07:00 AM
Megan Molteni
FOR THE PAST few years, up until the pandemic hit, Bill Ristenpart, a chemical engineer at UC Davis (and next-level coffee geek), had been bringing a team of researchers and crates of expensive instruments across the country each summer to New York City and into the lab of Nicole Bouvier. An infectious disease physician and researcher at Mount Sinai Hospital, Bouvier studies respiratory viruses, influenza A in particular. Ristenpart’s specialty is fluid dynamics. In the case of flu, that means measuring how physical properties like temperature, humidity, and wind speed change the flight of the respiratory bloblets that fly out of human and rodent noses and mouths. Together, with dozens of guinea pigs and nearly $2 million from the National Institutes of Health, they hoped to figure out a century-old mystery: Why is there a flu season?
... “Our experiments very clearly show that when guinea pigs move around they stir up dust. And if that dust is contaminated with virus, then it can transmit that virus through the air to another animal in a separate cage,” says Ristenpart. Their work also raises the possibility that this fourth route of transmission—aerosolized fomites—could potentially matter for human health as well, he says. Especially during a global outbreak of a new respiratory virus.
... The UC Davis/Mount Sinai team published these assumption-shaking findings Tuesday in the journal Nature Communications. Though the experiments were conducted pre-pandemic, and with an influenza virus, their results now land in the middle of a heated dispute about how the novel coronavirus SARS-CoV-2 is transmitted. At the heart of the controversy is disagreement over the size, behavior, and relative importance of the droplets that infected people emit from their respiratory tracts—specifically, whether those expiratory particles can travel long distances and stay airborne for long periods of time.
... That’s true for influenza, and it could also be true for SARS-CoV-2. Corsi points to a study conducted by Chinese researchers in February and March inside two Wuhan hospitals during the height of the initial Covid-19 outbreak. They collected aerosol samples from a variety of locations within the hospital and found that levels of airborne coronavirus were highest in rooms where medical staff changed out of their protective apparel. The authors hypothesized that the source of these viral aerosols—which were very small, smaller than a single micron—was from the disruption of removing contaminated clothing.
... Aerosol scientists have previously considered the possibility of influenza virus being transmitted via resuspension, or aerosolized fomites. Many that WIRED spoke to believe it’s plausible that SARS-CoV-2 could behave in much the same way. But they stressed that just because it can happen doesn’t mean it does, or that it does very often. “We do not know how important this route of transmission is compared to aerosols that are directly emitted,” Linsey Marr, an expert in airborne viruses at Virginia Tec ...
... because SARS-CoV-2 is such a new pathogen. Among its many unknowns is the amount of coronavirus required to infect someone. More investigation into that will be necessary to assess whether dust particles can transmit enough virus to make someone sick. But studying how important resuspended viral particles are for spreading a disease like Covid-19 or influenza in the real world is also incredibly difficult. Because scientists can’t really track individual particles into a person’s body to know which ones cause an infection, it’s next to impossible to tell if the viral particle that makes someone sick came from a respiratory droplet moving at them ...
https://www.wired.com/story/a-new-s...cial&utm_social-type=owned&utm_source=twitter
08.19.2020 07:00 AM
Megan Molteni
FOR THE PAST few years, up until the pandemic hit, Bill Ristenpart, a chemical engineer at UC Davis (and next-level coffee geek), had been bringing a team of researchers and crates of expensive instruments across the country each summer to New York City and into the lab of Nicole Bouvier. An infectious disease physician and researcher at Mount Sinai Hospital, Bouvier studies respiratory viruses, influenza A in particular. Ristenpart’s specialty is fluid dynamics. In the case of flu, that means measuring how physical properties like temperature, humidity, and wind speed change the flight of the respiratory bloblets that fly out of human and rodent noses and mouths. Together, with dozens of guinea pigs and nearly $2 million from the National Institutes of Health, they hoped to figure out a century-old mystery: Why is there a flu season?
... “Our experiments very clearly show that when guinea pigs move around they stir up dust. And if that dust is contaminated with virus, then it can transmit that virus through the air to another animal in a separate cage,” says Ristenpart. Their work also raises the possibility that this fourth route of transmission—aerosolized fomites—could potentially matter for human health as well, he says. Especially during a global outbreak of a new respiratory virus.
... The UC Davis/Mount Sinai team published these assumption-shaking findings Tuesday in the journal Nature Communications. Though the experiments were conducted pre-pandemic, and with an influenza virus, their results now land in the middle of a heated dispute about how the novel coronavirus SARS-CoV-2 is transmitted. At the heart of the controversy is disagreement over the size, behavior, and relative importance of the droplets that infected people emit from their respiratory tracts—specifically, whether those expiratory particles can travel long distances and stay airborne for long periods of time.
... That’s true for influenza, and it could also be true for SARS-CoV-2. Corsi points to a study conducted by Chinese researchers in February and March inside two Wuhan hospitals during the height of the initial Covid-19 outbreak. They collected aerosol samples from a variety of locations within the hospital and found that levels of airborne coronavirus were highest in rooms where medical staff changed out of their protective apparel. The authors hypothesized that the source of these viral aerosols—which were very small, smaller than a single micron—was from the disruption of removing contaminated clothing.
... Aerosol scientists have previously considered the possibility of influenza virus being transmitted via resuspension, or aerosolized fomites. Many that WIRED spoke to believe it’s plausible that SARS-CoV-2 could behave in much the same way. But they stressed that just because it can happen doesn’t mean it does, or that it does very often. “We do not know how important this route of transmission is compared to aerosols that are directly emitted,” Linsey Marr, an expert in airborne viruses at Virginia Tec ...
... because SARS-CoV-2 is such a new pathogen. Among its many unknowns is the amount of coronavirus required to infect someone. More investigation into that will be necessary to assess whether dust particles can transmit enough virus to make someone sick. But studying how important resuspended viral particles are for spreading a disease like Covid-19 or influenza in the real world is also incredibly difficult. Because scientists can’t really track individual particles into a person’s body to know which ones cause an infection, it’s next to impossible to tell if the viral particle that makes someone sick came from a respiratory droplet moving at them ...
https://www.wired.com/story/a-new-s...cial&utm_social-type=owned&utm_source=twitter