The novel coronavirus (2019-nCoV) shows evidence of causing gastrointestinal symptoms and has the potential to be transmitted by the fecal-oral route, according to a new report from physicians at Shanghai Jiao Tong University, published online (Gastroenterology. 2020 March 3. doi: 10.1053/j.gastro.2020.02.054).
The virus’s respiratory symptoms are well documented and suggest primary transmission by droplet or contact, while other symptoms such as diarrhea, nausea, vomiting, and abdominal discomfort are less common and appear to vary between populations. The SARS coronavirus showed up in stool, even sometimes in patients discharged from the hospital. In a study of hospitalized patients in Wuhan, China, 10.1% of coronavirus patients had diarrhea and nausea in the 1-2 days before onset of fever and dyspnea. Theto be diagnosed had a 2-day history of nausea and vomiting, and had a loose bowel movement on the second day in the hospital. Clinicians later confirmed the presence of viral RNA in both the patient’s stool and airway.
The authors say that researchers in China have isolated viral RNA from the stool of two patients (unpublished), and it, suggesting the possibility of the salivary gland as an infection or transmission route.
The authors maintain that previous studies likely overlooked or neglected patients who had mild intestinal symptoms. “Many efforts should be made to be alert on the initial digestive symptoms of COVID-19 for early detection, early diagnosis, early isolation and early intervention,” the authors wrote.
Like other coronaviruses, it appears that 2019-nCoV infects cells through an interaction between viral transmembrane spike glycoprotein (S-protein) receptor-binding domain, and the cell receptors angiotensin-converting enzyme 2 (ACE-2) and host cellular transmembrane serine protease (TMPRSS). Transcriptome analysis has shown that human lung AT2 cells express ACE-2 and TMPRSS, but esophagus upper and stratified epithelial cells also express both factors, as do stratified epithelial cells and absorptive enterocytes in the ileum and colon.
The researchers call for investigation into ACE-2 fusion proteins and TMPRSS inhibitors for diagnosis, prophylaxis, or treatment of COVID-19.
The authors also noted that COVID-19 has been linked to mild to moderate liver injury as revealed by elevated aminotransferases, hypoproteinemia and prothrombin time prolongation. This also has precedent in that the SARS coronavirus can infect the liver, and biopsies revealed mitoses and apoptosis, along with other abnormalities. SARS-associated hepatitis may be the result of viral hepatitis, immune overreaction, or a secondary effect of antiviral medications or other drugs. Little is known to date about the ability of 2019-nCoV to infect the liver, but single-cell RNA sequencing data from two distinct cohorts showed more ACE-2 expression in cholangiocytes (59.7%) than hepatocytes (2.6%), which indicates that the virus might directly affect intrahepatic bile ducts.
The authors did not disclose sources of funding or financial conflicts.