"The human intestinal tract might be a transmission route of SARS-CoV-2," the team wrote in their report, published in Nature Medicine.
They also found virus capable of infecting cells in stool taken from a patient with Covid-19.
"A 68-year-old female patient presented with fever, sore throat and productive cough and developed diarrhea after admission to Princess Margaret Hospital," Zhou and colleagues wrote. "We isolated infectious virus from her stool specimen," they added.
"Here we demonstrate active replication of SARS-CoV-2 in human intestinal organoids and isolation of infectious virus from the stool specimen of a patient with diarrheal COVID-19."
Separately, a team at University Medical Center Hamburg-Eppendorf in Germany performed autopsies on 27 patients who died from Covid-19. They found the virus in a variety of organs.
"SARS-CoV-2 can be detected in multiple organs, including the lungs, pharynx, heart, liver, brain, and kidneys," they wrote in a letter published in the New England Journal of Medicine.
The virus seemed to do especially well in the kidneys, they wrote -- something that might explain the high rate of kidney injury seen among Covid-19 patients.
The ability of the virus to attack various organs might aggravate pre-existing conditions, they added. People with heart disease, diabetes and kidney disease are especially vulnerable to the new coronavirus.