COVID-19: gastrointestinal symptoms and potential sources of SARS-CoV-2 transmission

A new type of coronavirus, i.e. se­vere acute respiratory syndrome coronavirus 2 (SARS-CoV-2; formerly known as 2019-nCoV) appeared in December 2019 in the province of Hubei, China, and over the past four months the number of cases of infection has exceeded 240,000 worldwide, leading to a pandemia [1]. At the genetic level, 2019-nCoV is closely related to the SARS-CoV and, to a lesser extent, to MERS-CoV, which appeared as epidemiological threats in recent years in China and the Middle East, respectively. Infections with the Coronaviridae virus family in a small percentage of patients, especially in those over 60 years of age with a positive clinical history, lead to severe acute respiratory syndrome [2].

GASTROINTESTINAL SYMPTOMS

Pneumonia in the course of 2019-nCoV coronavirus infection is characterised by fever, dry cough, and shortness of breath, all of which has been defined by the World Health Organisation as severe acute respiratory infection (SARI) [3, 4]. Droplet and contact transmission are definitely dominant in the spread of infection. The occurrence of less common symptoms, such as nausea, vomiting, abdominal discomfort, and diarrhoea, differs significantly depending on the study population; however, gastrointestinal symptoms can precede typical respiratory presentation [3]. The incidence of gastrointestinal symptoms, including nausea and/or diarrhoea, is uncertain; some authors report a frequency below 5%, while others report it to be as high as 50% [6].
The first patient with a confirmed 2019-nCoV infection in the United States presented with a two-day history of nausea and vomiting followed by diarrhoea from the second day of hospitalisation. Genetic material of the virus was identified in stool samples and nasopharyngeal and oropharyngeal swabs [7]. The SARS-CoV-2 virus genome can also be detected in the saliva of most infected patients, even without nasopharyngeal aspiration. Salivary samples taken serially from patients after hospitalisation showed a decrease in viral load, suggesting the possibility of salivary gland infection [8].
Evidence from earlier SARS studies indicates the tropism of SARS coronavirus (SARS-CoV-1) to the gastrointestinal tract cells. This was confirmed by positive tests for the presence of the microorganism in digestive tract biopsies and faeces, even in patients discharged from the hospital, which may partly explain the potential recurrence of the disease and persistent transmission [5]....


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