The coronavirus has raised fears it may spread via faecal matter after two people in the same apartment block were diagnosed.
The previously unknown strain, officially named Covid-19 on Tuesday, is thought to have emerged at a seafood and live animal market in the Chinese city Wuhan at the end of last year.
In less than two months, more than 45,000 cases have been confirmed, of which 44,685 are in mainland China, according to John Hopkins University.
It has also crossed national borders into at least 27 countries, with eight confirmed patients in the UK.
Read more: Coronavirus officially named Covid-19
The death toll exceeded 1,100 on Wednesday.
Unheard of several weeks ago, little is known about the virus, including how it spreads.
The only known method of transmission is droplets expelled while sneezing or coughing.
It is unknown whether the virus “floats” in the air, survives on hard surfaces or spreads via faecal matter.
The latter concern has come to light about after two residents of a Hong Kong apartment block caught Covid-19, despite living on different floors.
An unnamed 62-year-old woman became the second infected resident, with the first living 10 floors below her.
Officials later found an unsealed pipe in her bathroom, potentially allowing the virus into her apartment.
Does the new coronavirus Covid-19 spread via faecal matter?
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 World Health Organization (WHO) concluded in 2003 “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”.
Speaking at the time, Dr Jamie Bartram from the WHO, said: “In many countries there will be buildings where keeping sewage separate from building occupants is a critical challenge.
“This could result in harmful viruses, including Sars, being sucked from the sewage system into the home if, for example, there are strong extractor fans working in a family’s bathroom”.
Hundreds of residents of Hong Kong’s housing estate Amoy Gardens also caught Sars after “a rising plume of warm air originating in bathrooms contaminated several apartments and was transported by wind to adjacent buildings in the complex”.
Dr Bartram stressed, however, Sars was “overwhelmingly” spread via face-to-face “water droplets”.
Genetic analyses reveal Covid-19 is more similar to Sars than any other coronavirus strain.
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 (ICTV) is calling it “severe acute respiratory syndrome coronavirus 2” (SARS-CoV-2).
“The ICTV have determined it is the same species as Sars but a different strain of the species”, said Dr Nathalie MacDermott from King’s College London.
When it comes to Covid-19 potentially “leaking” through the woman’s unsealed pipe, Dr Amesh Adalja told Live Science the virus could theoretically have become “aerosolised”.
Faecal samples from infected patients have tested positive for Covid-19, with some also experiencing diarrhoea.
In general, however, symptoms tend to be flu-like.
Speaking of initial Covid-19 cases in China on 24 January, Professor Tom Solomon - from the National Institute for Health Research - said: “Fever, cough, fatigue and shortness of breath were common (occurring in at least half the patients who needed hospital admission).
“In contrast of upper respiratory tract symptoms, such as a runny nose and sore throat were not seen.
“Nor was diarrhoea which affected a quarter of the patients with Sars”.
What is the new coronavirus Covid-19?
Most of the people who initially became unwell worked at, or visited, the market in Wuhan.
Wuhan, capital of Hubei province, has about 11 million residents.
While no one can say for sure where the disease came from, bats seem most likely.
The nocturnal creatures are also thought to have been behind Sars and fellow coronavirus Middle Eastern respiratory syndrome (Mers), which killed 858 people during its 2012 outbreak.
Scientists from Peking University in Beijing have suggested snakes may have been the “intermediate host” for Covid-19.
A team from South China Agricultural University have since found it could have “jumped” from bats to humans via pangolins.
In the most severe cases, victims succumb to pneumonia.
This comes about when a respiratory 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.”
The US Centers for Disease Control and Prevention has warned there is no specific treatment for coronaviruses.
If the infection triggers pneumonia, doctors work to combat the complication.
Pneumonia is generally caused by bacteria, which tend to respond to antibiotics.
When a virus is to blame, like 2019-nCoV, it may be treated via “antiviral medication”.
However Professor Peter Horby, from the University of Oxford, claimed there is “no effective anti-viral”, with treatment being “supportive” while the immune system works to fight off the virus.