Study offers a non-obtrusive avenue for monitoring buildings for COVID-19

Overview

• Post By :


• Source: Ohio State University


• Date: 14 Apr,2021

A study done in rooms where COVID-19 patients were isolated reveals that the virus’s RNA – part of the genetic material inside a virus – can persist up to a month in dust.

The study did not evaluate whether dust may transmit the virus to people. It could, however, offer another option for monitoring COVID-19 outbreaks in specific buildings, including nursing homes, schools or offices.

Karen Dannemiller, senior author of the research, has experience analyzing dust and its relationship to possible hazards like mold and germs.

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

“And we have spent so much time studying dust and flooring that we knew how to test it.”

The study, published today (April 13, 2021) in the journal mSystems, discovered some of the genetic material at the center of the virus stays in dust, even though it’s very likely that the envelope around the virus may break down over time in dust. The envelope – the crown-like spiked sphere that contains the virus’s substance – plays an significant role in the virus’s transmission to people.

Municipalities and others have tested wastewater to assess the incidence of COVID-19 in a specific community – gene copies and fragments of the virus live in human waste, and by testing wastewater, local authorities and others can determine how widespread the virus might be, even if people are asymptomatic.

Dust monitoring could offer similar comprehension on a smaller scale – say, a particular nursing home, hospital or school.

“In nursing homes, for instance, you’re still going to have to understand how COVID is spreading inside the building,” said Nicole Renninger, lead author of the paper and an engineering graduate student in Dannemiller’s lab. “For surveillance functions, you will need to know if you’re picking up an outbreak that’s going on right now.”

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

The researchers also tested swabs collected from 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 dust samples and in 55% of the surface swabs.

The cleaning crews sprayed a chlorine-based disinfectant in the rooms before cleaning; the researchers feel that disinfectant ruined the envelope and/or capsid – the outer coat surrounding the virus – probably defanging it for transmission.

The research team tested the samples when they arrived at the laboratory, shortly after the rooms were washed, then tested the samples weekly. After four weeks, the virus’s RNA didn’t significantly decay in the vacuum bags.

“We weren’t certain that the genetic material could survive – there are several different organisms in dust, and we weren’t sure we would see any viral RNA at all,” Renninger said. “And we were amazed when we discovered the real RNA itself seems to be lasting a pretty long time.”

Testing dust to track for COVID-19 outbreaks will likely be useful for smaller-scale communities with a high-risk inhabitants – a nursing home, for example, Dannemiller said. Testing indoor dust is also probably less expensive at that scale than testing wastewater or all individuals directly on a regular basis.

“Wastewater is terrific for a huge population, but not everyone sheds the virus in feces, and you need to collect wastewater samples, which not everyone wants to do. People are already vacuuming these rooms, so dust may be a fantastic solution for some groups.”

Before this analysis was published, Dannemiller said the investigators presented their findings to an industry group that represents maintenance and cleaning staff, with a recommendation:”If they can wait at least an hour or more after a person leaves the room to clean, they ought to,” she said, citing previous studies of viral viability on other substances and in aerosols.