The novel coronavirus is shed in the feces of infected people, which may help explain why it’s spread so fast, according to Chinese researchers.
The finding of live virus particles in stool specimens indicates a fecal-oral route for coronavirus, which may be why it’s caused outbreaks on cruise ships with an intensity often seen with gastro-causing norovirus, which also spreads along that pathway. More than 600 Covid-19 infections were confirmed among passengers and crew aboard the Diamond Princess, the ship quarantined for two weeks in Yokohama, Japan.
“This virus has many routes of transmission, which can partially explain” its rapid spread, the Chinese Center for Disease Control and Prevention said in a report Saturday.
The agency recommends strengthening sanitation and hygiene measures to prevent fecal-oral transmission in epidemic area. These include drinking boiled water, avoiding eating raw food, implementing separate meal systems, frequent hand-washing, disinfecting toilets, and preventing water and food contamination from patients’ stool.
“The virus can also be transmitted through the potential fecal-oral route,” the Chinese CDC said. “This means that stool samples may contaminate hands, food, water” and cause infection when the microbes enter the mouth or eyes, or are inhaled, they said.
Rectal swabs can detect the pneumonia-causing virus in patients even when conventional oral tests are negative, doctors at the Wuhan Pulmonary Hospital in central China said in a study.
The novel SARS-like coronavirus was found in oral and anal swabs, and blood — indicating that infected patients may shed the pathogen through respiratory, fecal-oral or body fluid routes, the authors said.
They showed that the current strategy for detecting viral RNA in oral swabs used to diagnose Covid-19 cases “is not perfect,” the researchers said. They noted that patients may harbor the virus in the intestine at the early or late stage of disease, and that a blood test for antibodies against the virus should be considered to better understand patterns of infection.
The coronaviruses that cause Covid-19 and SARS, or severe acute respiratory syndrome, bind to the same distinctly shaped protein receptors in the body that are expressed in the lungs and intestines, making these organs the primary targets for both viruses, said Fang Li, an associate professor of veterinary and biomedical sciences at the University of Minnesota, last month.
A virus-laden aerosol plume emanating from a SARS patient with diarrhea was implicated in possibly hundreds of cases at Hong Kong’s Amoy Gardens housing complex in 2003.
That led the city’s researchers to understand the importance of the virus’s spread through the gastrointestinal tract, and to recognize both the limitation of face masks and importance of cleanliness and hygiene, according to John Nicholls, a clinical professor of pathology at the University of Hong Kong.
Squat latrines, common in China, lacking covers and hands that aren’t washed thoroughly with soap and water after visiting the bathroom, could be a source of virus transmission, said Nicholls, who was part of the research team that isolated and characterized the SARS virus.
More must-read stories from Fortune:
—Mapping a contagion: How the coronavirus may spread around the world
—Frustrations fly as MWC trade show customers seek refunds following last-minute cancelation
—In China, oil won’t be the only energy sector battered by the coronavirus
—Coronavirus recovery: Why it’s so hard for China’s factories to get back to work
—Coronavirus may be the straw that breaks the back of oil fracking
Subscribe to Fortune’s Brainstorm Health for daily updates on biopharma and health care.
