Tracking COVID-19 in Our Dust May Help Predict Outbreaks

COVID-19 genetic material can survive in dust for up to a month, a new study finds, which offers a potentially inexpensive way to detect outbreaks.

Finding does not mean that viruses can be transmitted via dust.

A study conducted in rooms where COVID-19 patients were isolated shows that the RNA of the virus – part of the genetic material in a virus – can persist in dust for up to a month.

The study did not evaluate whether dust can transmit the virus to humans. However, it could provide another option for monitoring COVID-19 outbreaks in specific buildings, including nursing homes, offices or schools.

Karen Dannemiller, senior author of the study, has experience studying dust and its relationship to potential hazards such as fungi and microbes.

“When the pandemic started, we really wanted to find a way to contribute knowledge that could help mitigate this crisis,” said Dannemiller, assistant professor of civil engineering, environmental and geodetic engineering, and environmental health sciences at Ohio State University.

“And we spent so much time studying fabric and floors that we knew how to test it.”

The study, published April 13, 2021, in the journal mSystems, found that some of the genetic material in the heart of the virus persists in dust, even though the envelope surrounding the virus is likely to become dust over time. can fall apart. The envelope – the crown-like pointed sphere that contains the material of the virus – plays an important role in the transmission of the virus to humans.

The study offers another non-invasive way to monitor buildings for COVID-19 outbreaks, especially as more people are being vaccinated and returning to communal areas.

Municipalities and others have tested wastewater to evaluate the prevalence of COVID-19 in a particular community – gene copies and fragments of the virus live in human waste, and by testing wastewater, local governments and others can determine how widespread the virus could be even when people are asymptomatic.

Substance monitoring could provide similar insights on a smaller scale, for example a specific nursing home, hospital or school.

“In nursing homes, for example, you still need to know how COVID spreads in the building,” said Nicole Renninger, lead author of the paper and an engineering student in Dannemiller’s lab. “For surveillance purposes, you need to know if you notice an outbreak that is currently underway.”

For this study, the research team worked with the crews responsible for cleaning the rooms in the state of Ohio, where students who tested positive for COVID-19 were isolated. They also collected samples from two homes where people lived who tested positive for COVID-19. They collected vacuum cleaner bags from the cleaning crews and from the houses.

The researchers also tested cotton swabs collected on surfaces in the rooms.

They found genetic material from the SARS-CoV-2 virus – the virus that causes COVID-19 – in 97% of the bulk fabric samples and 55% of the surface wadding.

The cleaning crews sprayed a chlorine-based disinfectant into the rooms before cleaning them; the researchers believe the disinfectant destroyed the envelope and / or capsid – the outermost layer surrounding the virus – and likely protected it from transmission.

The research team tested the samples upon arrival at the lab, shortly after the chambers were cleaned, and then retested the samples weekly. After four weeks, the virus RNA did not decay significantly in the vacuum bags.

“We weren’t sure if the genetic material would survive – there are many different organisms in dust, and we weren’t sure if we would see viral RNA at all,” Renninger said. “And we were surprised to find that the actual RNA itself seems to take quite a long time.”

Fabric testing to check for COVID-19 outbreaks would likely be most helpful for smaller communities with a high-risk population – a nursing home, for example, Dannemiller said. Indoor dust testing is also likely to be less expensive on that scale than routine testing of wastewater or all individuals.

“We wanted to show that dust can supplement wastewater for surveillance,” said Dannemiller. “Wastewater is great for a large population, but not everyone spreads the virus in their stools, and you have to collect wastewater samples, which not everyone wants. People are already vacuuming these rooms, so dust may be a good option for some groups. “

Even before this study was published, Dannemiller said the researchers presented their findings to an industry group representing maintenance and cleaning personnel, with a recommendation, “ If they can wait at least an hour or more after someone leaves the room to clean, ” should, ”she said, citing previous studies of viral viability on other materials and in aerosol cans.

Reference: “Indoor Dust as a Matrix for Surveillance of COVID-19” by Nicole Renninger, Nicholas Nastasi, Ashleigh Bope, Samuel J. Cochran, Sarah R. Haines, Neeraja Balasubrahmaniam, Katelyn Stuart, Aaron Bivins, Kyle Bibby, Natalie M. Hull and Karen C. Dannemiller, Apr 13, 2021, mSystems.
DOI: 10.1128 / mSystems.01350-20

Other Ohio State researchers who contributed to this study include Nick Nastasi, Ashleigh Bope, Samuel Cochran, Sarah Haines, Neeraja Balasubrahmaniam, Katelyn Stuart, and Natalie Hull. Kyle Bibby, an associate professor of engineering at the University of Notre Dame, and Aaron Bivins, a postdoctoral fellow in his group, also contributed.