Viral RNA found in the stool of patients with COVID-19 suggested that the SARS-CoV-2 virus persists longer in the gastroenterological tract than in the respiratory system for some individuals, indicating a risk for fecal-oral transmission of the virus. Results from this study were published in Gastroenterology.
Between February 1st and 14th, 2020 clinical samples (blood serum, nasopharyngeal and oropharyngeal swabs, urine, and stool) were collected from 73 patients hospitalized with SARS-CoV-2 in China. In addition, esophageal, gastric, duodenal, and rectal tissues were collected from 1 of the patients via endoscopy. Real-time reverse transcriptase polymerase chain reaction (rRT-PCR) targeting the viral receptor angiotensin converting enzyme 2 (ACE2) and histologic staining for ACE2 and nucleocapsid were performed on the collected specimens.
The majority of patients (53.4%) tested positive for viral RNA in their stool. Positive test results persisted from 1 to 12 days in the stool samples. Nearly a quarter (23.3%) of patients had a positive result that persisted after respiratory tract specimens returned a negative result.
Investigators did not observe significant damage to mucosal epithelium of tissues in the esophagus, stomach, duodenum, or rectum. They did observe minor infiltration of lymphocytes in the esophageal squamous epithelium and major infiltration with interstitial edema in lamina propria of the stomach, duodenum, and rectum. Viral ACE2 were observed in the cytoplasm of gastrointestinal epithelial cells and were abundantly distributed on the cilia of glandular epithelial cells. Viral nucleocapsid protein was observed in the cytoplasm of gastric, duodenal, and rectal glandular epithelial cells.
A significant limitation of the study was that all the histological data were based on samples provided by a single patient, which is a potential source of bias.
The study authors concluded that the risk for fecal-oral transmission of COVID-19 should be accounted for in clinical practice. Currently, patients with COVID-19 are discharged from the hospital after 2 consecutive negative tests of the virus by respiratory swabs, however these data indicate that 23% of patients would still have an active infection in their gastrointestinal tract at time of discharge. Therefore, it the recommendation of these investigators to incorporate rRT-PCR testing for viral RNA in stool samples before discharging patients.
Xiao F, Tang M, Zheng X, et al. Evidence for gastrointestinal infection of SARS-CoV-2. [available online March 3, 2020] Gastroenterology doi:10.1053/j.gastro.2020.02.055.