Sewage From Toilet in Chinese City Infected Six People with Coronavirus in First Known Case of Its Kind

Half a dozen people in China are thought to have caught the coronavirus from sewage, in what scientists believe is the first example of the virus spreading in this way.

According to a study published in the journal Clinical Infectious Diseases a bathroom pipe running from the home of a couple with the coronavirus had a hole in it. When it rained in the area, the hole caused the sewage to flood the streets, enabling the virus to infect nearby residents.

The authors said the findings highlight the importance of managing sewage correctly, particularly in densely populated areas where hygiene and sanitation measures are poor.

The team, which included scientists from public health departments in China, took throat swabs from 2,888 residents in a community in the city of Guangzhou during a COVID-19 outbreak. The team also collected samples from surfaces inside and around their homes. The participants were ordered or asked by officials to quarantine at home, depending on how close they lived to the infected couple, who were the first two cases. The were referred to as cases one and two in the study.

Cases one and two visited a market for their work, where there was an ongoing COVID-19 outbreak, on March 27 and April 3. The couple were diagnosed with the coronavirus after they were found by contact tracers.

Between April 5 to 21, six people who lived in a separate building adjacent to the home of cases one and two tested positive for the coronavirus. The authors interviewed the residents and found they did not visit the market, and had no contact with the first cases.

It was later discovered that a sewage pipe connected to the toilet of cases one and two, which ran along the wall outside their building, had a 100cm squared (39 inch) hole. The researchers poured water in the couple's toilet and found water poured out of the hole into an alley, ran into five drains near the building, and onto the entrances to the buildings whether the secondary cases lived.

The authors examined the genetic makeup of the coronavirus samples. They found that the viruses found on a toilet and the dirt on the bottom of the shoes of cases one and two matched up with the viruses that cases three and eight were infected with. It was also in the sewage of the secondary cases.

The other cases took the virus into their homes via their shoes and bicycle tires, the team believes.

Evidence suggests that people with the coronavirus likely shed the virus the most when their symptoms start. The team noted that it rained when cases one and two were first showing symptoms.

toilet, stock, getty
A stock image shows a person closing a toilet lid. Scientists believe the coronavirus can spread in sewage. Getty

Acknowledging the limitations of the study, the authors said they could no provide definitive proof that the sewage caused the outbreak, although this seems the most likely explanation.

The coronavirus has previously been found in the feces of COVID-19 patients, and scientists are seizing on this fact to explore whether wastewater can be used to predict future outbreaks. As the virus continues to spread around the world, with over 406,000 new cases reported on Thursday alone according to Johns Hopkins University, scientists are working to find ways to pinpoint clusters and prevent further transmission. Since the coronavirus was first reported in China late last year, over 38.9 million people have been infected, and more than one million have died.

Ian Jones, professor of virology at the U.K.'s University of Reading who did not work on the study, told Newsweek: "The impressive detection work done in this study clearly shows that this is the case with likely transmission on a local scale via contaminated sewage. But it's important to keep the study in perspective." Jones said the spread was linked to a broken sewage pike and people not changing their shoes, "both of which are correctable."

He said: "It's a reminder of the importance of infrastructure barriers like waste disposal, which need to be maintained in good order to minimize the risk to local workers as well as the surrounding society they service."