The coronavirus could spread in a patient’s urine or faeces, according to an official report.
The World Health Organization (WHO)-China Joint Mission on Coronavirus Disease 2019 notes “viral shedding” has occurred in human waste.
China’s National Health Commission has since confirmed traces of the virus in patients’ stool samples.
Most experts are unsurprised by the findings, but stress human waste is unlikely the main method of transmission.
The new coronavirus strain Covid-19 emerged at a seafood and live animal market in the Chinese city Wuhan at the end of last year.
It has since spread to more than 60 countries, with the number of confirmed cases worldwide exceeding 94,200 on Wednesday, according to John Hopkins University data.
While over 80,200 of these are in mainland China, outbreaks are arising thousands of miles away.
South Korea has more than 5,600 confirmed cases and 35 deaths.
Italy is the worst affected country in Europe, with over 2,500 incidences and 79 fatalities.
Out of more than 13,000 tests carried out in the UK, 85 have come back positive.
One British man died after catching the infection aboard the “hotbed” Diamond Princess cruise ship.
The global death toll exceeded 3,100 on Wednesday.
While it may sound alarming, more than 51,000 people have “recovered”.
Research into the first 44,000 confirmed cases in China also found 80.9% were mild, 13.8% severe and just 4.7% critical.
How does the coronavirus Covid-19 spread?
Officials confirmed early in the outbreak Covid-19 is transmitted face-to-face via infected droplets sneezed or coughed out by a patient.
Prevention therefore largely centres on maintaining “social distancing”, with one expert calling two metres (6.5ft) “reasonable”.
Fears Covid-19 may spread via faecal matter arose in mid-February when two people living 10 floors apart in the same Hong Kong apartment block were diagnosed.
Officials later found an unsealed pipe in one of the patient’s bathroom, which could have allowed the virus into her apartment.
Covid-19 is one of seven strains of the coronavirus class that are known to infect humans.
Another is severe acute respiratory syndrome (Sars), which killed 774 people during its 2004 outbreak.
The WHO concluded “inadequate plumbing” was a “likely contributor” to the spread of Sars in “residential buildings in Hong Kong”.
“Virus rich excreta” was thought to have “re-entered residents’ apartments” via “sewage and drainage systems where there were strong upward air flows, inadequate ‘traps’ and non-functional water seals”.
Scientists from Fudan University in Shanghai found Covid-19 appears to be 89.1% genetically similar to “a group of Sars-like coronaviruses”.
Although named Covid-19 by the WHO, the International Committee on Taxonomy of Viruses is calling it “severe acute respiratory syndrome coronavirus 2” (Sars-CoV-2).
When asked about Covid-19’s transmission in human waste, Dr Simon Clarke – from the University of Reading – said: “Viruses can often be spread by a range of bodily secretions.
“In the case of respiratory infections, such as Covid-19, it’s most often mucus or spit, but other coronaviruses have been shown to transmit in different ways.
“For example, we know Sars can be transmitted via urine and faeces, but Mers will not.”
Mers (Middle Eastern respiratory syndrome), another coronavirus, killed 858 people globally during its 2012 outbreak.
“The WHO does not think [human waste] is a main driver of the [Covid-19] outbreak,” Dr Devi Sridhar from the University of Edinburgh told Yahoo UK.
“The focus is on respiratory pathways (droplets spread through coughing, sneezing and through hands touching contaminates surfaces).”
One expert questioned, however, whether the viral traces in patients’ stools are infectious.
“It isn’t a very pleasant thought, but every time you swallow, you swallow mucus from your upper respiratory tract,” said Dr John Edmunds from the London School of Hygiene & Tropical Medicine.
“This sweeps viruses and bacteria down into our gut, where they are denatured in the acid conditions of our stomach.
“With modern, very highly sensitive detection mechanisms we can detect these viruses in faeces.
“Usually, viruses we can detect in this way are not infectious to others, as they have been destroyed by our guts.”
Unlike Sars, Covid-19 is not generally causing diarrhoea, which would be an expected symptom if the infection were spreading in faeces.
What is the coronavirus Covid-19?
Most of those who initially became unwell worked at, or visited, the “wet market” in Wuhan.
In severe cases, pneumonia can come about when the infection causes the alveoli (air sacs) in the lungs to become inflamed and filled with fluid or pus.
The lungs then struggle to draw in air, resulting in reduced oxygen in the bloodstream.
“Without treatment the end is inevitable,” said the charity Médecins Sans Frontières.
“Deaths occurs because of asphyxiation.”
Covid-19 is thought to have started in bats before “jumping” into humans, possibly via snakes or pangolins.
There is no specific treatment, with care being “supportive” while a patient’s immune system works to fight off the infection.
Officials recommend regular hand washing to stem Covid-19’s transmission.