Novel coronavirus may cause environmental contamination through fecal shedding
The toilet bowl, sink, and bathroom door handle of an isolation room housing a patient with the novel coronavirus tested positive for the virus, raising the possibility that viral shedding in the stool could represent another route of transmission, investigators reported.
CDC/ Dr. Fred Murphy; Sylvia Whitfield
Air outlet fans and other room sites also tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), though an anteroom, a corridor, and most personal protective equipment (PPE) worn by health care providers tested negative, according to the researchers, led by Sean Wei Xiang Ong, MBBS, of the National Centre for Infectious Diseases, Singapore.
Taken together, these findings suggest a “need for strict adherence to environmental and hand hygiene” to combat significant environmental contamination through respiratory droplets and fecal shedding, Dr. Ong and colleagues wrote in JAMA.
Aaron Eli Glatt, MD, chair of medicine at Mount Sinai South Nassau in New York, said these results demonstrate that SARS-CoV-2 is “clearly capable” of contaminating bathroom sinks and toilets.
“That wouldn’t have been the first place I would have thought of, before this study,” he said in an interview. “You need to pay attention to cleaning the bathrooms, which we obviously do, but that’s an important reminder.”
The report by Dr. Ong and coauthors included a total of three patients housed in airborne infection isolation rooms in a dedicated SARS-CoV-2 outbreak center in Singapore. For each patient, surface samples were taken from 26 sites in the isolation room, an anteroom, and a bathroom. Samples were also taken from PPE on physicians as they left the patient rooms.
Samples for the first patient, taken right after routine cleaning, were all negative, according to researchers. That room was sampled twice, on days 4 and 10 of the illness, while the patient was still symptomatic. Likewise, for the second patient, postcleaning samples were negative; those samples were taken 2 days after cleaning.
However, for the third patient, samples were taken before routine cleaning. In this case, Dr. Ong and colleagues said 13 of 15 room sites (87%) were positive, including air outlet fans, while 3 of 5 toilet sites (60%) were positive as well, though no contamination was found in the anteroom, corridor, or in air samples.
That patient had two stool samples that were positive for SARS-CoV-2, but no diarrhea, authors said, and had upper respiratory tract involvement without pneumonia.
The fact that swabs of the air exhaust outlets tested positive suggests that virus-laden droplets could be “displaced by airflows” and end up on vents or other equipment, Dr. Ong and coauthors reported.
All PPE samples tested negative, except for the front of one shoe.
“The risk of transmission from contaminated footwear is likely low, as evidenced by negative results in the anteroom and corridor,” they wrote.
While this study included only a small number of patients, Dr. Glatt said the findings represent an important and useful contribution to the literature on coronavirus disease 2019 (COVID-19).
“Every day we’re getting more information, and each little piece of the puzzle helps us in the overall management of individuals with COVID-19,” he said in the interview. “They’re adding to our ability to manage, control, and mitigate further spread of the disease.”
Funding for the study came from the National Medical Research Council in Singapore and DSO National Laboratories. Dr. Ong and colleagues reported no conflicts of interest.
SOURCE: Ong SWX et al. JAMA. 2020 Mar 4. doi: 10.1001/jama.2020.3227.
