• Recent research is shedding new light on virus transmission.
• The study, focussing on the influenza virus, shows the virus can “stick” to non-respiratory particles, such as dust.
• These results have major implications for the Covid-19 pandemic.

Influenza (flu) viruses spread among humans in various ways, such as via exhaled droplets or secondary objects like door handles and used tissues. These secondary objects are known as fomites.

A new study, however, provides new evidence of a mode of transmission seldom considered in influenza: airborne transmission on microscopic particles, called “aerosolised fomites”.

The research, by the University of California, Davis (UC Davis) and the Icahn School of Medicine at Mount Sinai, also has obvious implications for coronavirus transmission.

The findings were published in Nature Communications.

Airborne viruses can ‘catch a ride’ on fibres

For the new study, UC Davis engineering graduate students teamed up with virologists at Mount Sinai to investigate whether tiny, non-respiratory particles, or aerosolised fomites, could carry the influenza virus between guinea pigs.

The team used an automated particle sizer to count airborne particles and found that uninfected guinea pigs gave off spikes of up to 1 000 particles per second as they moved around the cage. Particles given off by the animals’ breathing, however, were at a constant, much lower rate.

The influenza virus was then painted on the fur of immune guinea pigs. Findings indicated that they could transmit the virus through the air to other guinea pigs. This means that airborne viruses may not have to come directly from the respiratory tract to be infectious.

The researchers also tested whether microscopic fibres from an inanimate object could carry infectious viruses. To do this, they treated paper facial tissues with influenza virus and let them dry out. Following this, they crumpled the tissues in front of the automated particle sizer.

The tissues were found to release up to 900 particles per second in a size range that could be inhaled, the study results show. More than this, the particles released from the virus-contaminated paper tissues were able to infect cells.

‘Dust transmission opens up new areas of investigation’

“It’s really shocking to most virologists and epidemiologists that airborne dust, rather than expiratory droplets, can carry influenza virus capable of infecting animals,” said Professor William Ristenpart of the UC Davis Department of Chemical Engineering, who was involved in the study.

“The implicit assumption is always that airborne transmission occurs because of respiratory droplets emitted by coughing, sneezing or talking.

“Transmission via dust opens up whole new areas of investigation and has profound implications for how we interpret laboratory experiments, as well as epidemiological investigations of outbreaks.” 

READ: Covid-19: Practical guidance on disinfecting

READ: Importance of wearing masks during Covid-19 pandemic – amid concerns over aerosol spread

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Compiled by Zakiyah Ebrahim

• Many people who normally work in offices have spent the last five months working from home 
• While working at home, extra care should be taken to avoid ergonomic injuries
• It’s also important to alter your position and change it throughout the day

If you’re working from a home office these days, it’s important to have an environment that won’t injure you, an expert says.

It’s good to have a break about every 30 minutes to protect your back, shoulders and arms, said Kermit Davis, an expert in office ergonomics at the University of Cincinnati College of Medicine.

“The body doesn’t like static postures continually,” he said. “You don’t want to do all sitting or all standing all the time. You want to alter your position and change it up throughout the day.”

Davis said that while you can work at home, you can’t take home all the comforts of your office.

Revealing statistics

“You can use your laptop from home, but it is designed to be a short-term option,” he said. “It should be used for a few hours while travelling. It is not meant to be used for eight or nine hours each day.”

An evaluation of home workstations of university employees who began working at home during the coronavirus pandemic was revealing. Many chairs were the wrong height: 41% were too low; 2% were too high. Although 53% of workers’ chairs had armrests, 32% didn’t use them and 18% were improperly adjusted.

Not using armrests can put stress on forearms and strain in the upper back. The evaluation also found that 69% were not using the chairback for support and 73% did not use lower-back support.

Computer monitors were often positioned too low or off to the side. Three-quarters of monitors were laptops, which were too low relative to a worker’s eye height, the study found.

Fifty-two percent of external monitors were also too low; 4% were too high. Also, 31% of monitors were not centred, causing neck or back twisting.

The following tips might be helpful for homebound office workers:

• Put a pillow on your seat to raise it.
• Put a pillow or rolled-up towel behind your back for lumbar support.
• If armrests are too low, wrap them.
• Bring the chair closer to the desk or table.
• Use a lap desk or pillow under the laptop to raise the monitor.
• Use an external keyboard and mouse, and raise the monitor using a stack of books or a box.
• For a standing workstation, the top of the monitor should be at eye level. The keyboard height should keep the forearms parallel to the ground.
• If you don’t have a proper work area, rotate between a sitting and a standing workstation.

Davis fears discomfort will increase after more than five months of working at home.

“It’s not just ergonomics changing but also other factors: isolation, teamwork changes and work-life balance is distorted, and changes in the stress level that people have,” he said.

The report was published online recently in the journal Ergonomics in Design.

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