Covid-19 patients have active and prolonged gut viral infection, even in the absence of gastrointestinal symptoms, scientists in Hong Kong showed.
The coronavirus may continue to infect and replicate in the digestive tract after clearing in the airways, researchers at the Chinese University of Hong Kong said in a statement Monday. The findings, published in the medical journal GUT, have implications for identifying and treating cases, they said.
SARS-CoV-2 spreads mainly through respiratory droplets -- spatters of virus-laden discharge from the mouth and nose, according to the World Health Organization. Since the first weeks of the pandemic, however, scientists in China have said infectious virus in the stool of patients may also play a role in transmission.
Cells containing coronavirus seen through a microscope
A February study of 73 patients hospitalized with the coronavirus in China’s Guangdong province found more than half tested positive for the virus in their stool.
The Hong Kong scientists studied stool samples from 15 patients to better understand the virus’s activity in the gastrointestinal tract. They found active gut infection in seven patients, some of whom had no nausea, diarrhea or other digestive symptoms. Three patients continued to display active viral infection as long as six days after their respiratory samples tested negative for Covid-19.
A worker wearing personal protective equipment holds a tray containing unlabeled ampoules of the Covid-19 vaccine
The finding “highlights the importance of long-term coronavirus and health surveillance and the threat of potential fecal-oral viral transmissions,” Siew Chien Ng, associate director of the university’s Centre for Gut Microbiota Research, said in the statement.
Treatments that modulate the composition and functionality of the gut microbiome should be explored, according to Ng. The gut bacteria of patients who were particularly infectious showed a loss of protective microbes and a proliferation of disease-causing ones.