Two new papers highlight the importance of the gastrointestinal tract in symptoms and spread of coronavirus.
Novel coronavirus symptoms seem to be mostly focused on fever and cough, but gastrointestinal symptoms should be a new focus for clinicians, according to 2 new papers published online in Gastroenterology.
The first paper describes how investigators from Shanghai, China, sought to document the symptoms of the novel coronavirus. Although fever, dry cough, and dyspnea present in most cases, they wanted to understand what impact the virus had on symptoms such as diarrhea, nausea, vomiting, and abdominal discomfort. So far, those symptoms have varied among different study populations, the authors wrote.
Former studies on SARS, which is related to the coronavirus and can present with similar symptoms, showed that SARS was verified in patients after detection in biopsy specimens and stool. This was true even after the patients had been discharged from the hospital.
The study authors noted that the first US patient admitted to a hospital with confirmed coronavirus had a loose bowel movement on hospital day 2. Labs in China have been able to isolate the live coronavirus from stool of patients, the study authors said. These factors brought the gastrointestinal tract to the forefront of investigators’ minds and suggest that clinicians should identify patients with gastrointestinal symptoms and carefully monitor those patients.
Another similarity the study authors noted between SARS and COVID-19 is that mild to moderate liver injury has existed in patients. Little is known about coronavirus infection in the liver but SARS in liver tissue confirmed coronavirus direct infection in livers, they said.
In the second paper, investigators from Guangdong Province in China examined the viral RNA in feces from 71 patients with confirmed COVID-19 during their hospitalization between Feb. 1-14, 2020. They collected serum, nasopharyngeal and oropharyngeal swabs, urine, stool, and tissues (from endoscopy) from the patients.
The age of the patients ranged from 10 months to 78 years old, the investigators said. The duration of positive stool tests ranged from 1 to 12 days, they added, and patients remained positive via stool tests after showing negative in respiratory samples.
The study authors said that viral host receptor ACE2 stained positive primarily in the gastrointestinal epithelial cells, which is rare. ACE2 is “abundantly distributed in cilia of glandular epithelia,” the study authors said, but rarely expressed in esophageal epithelium. This is likely due to esophageal epithelium mainly being composed of squamous epithelial cells, which express less ACE2 than glandular epithelial cells.
Although the first study suggests that the infectious virions can be released into the gastrointestinal tract, the second paper suggests that fecal-oral transmission could be a path for viral spread.
“Preventing fecal-oral transmission should be taken into consideration to control the spread of the virus,” the second study’s authors wrote. “Our results highlight the clinical significance of testing viral RNA in feces by rRT-PCR since infectious virions released from gastrointestinal tract can be monitored by the test.”
Guidelines from the US Centers for Disease Control and Prevention recommend discontinuing rRT-PCR testing for coronavirus patients after 2 sequential respiratory tract specimens collected greater than 24 hours apart come back negative. However, the investigators noted that they observed more than 20% of their patients had viral RNA that remained positive even after respiratory tract tests indicated negative results.
“Therefore, we strongly recommend that rRT-PCR testing for coronavirus from feces should be performed routinely in coronavirus patients, and Transmission-Based Precautions for hospitalized coronavirus patients should continue if feces tests positive by rRT-PCR testing.”