Diarrhea May Be First or Only Coronavirus Symptom in COVID-19 Patients Experience, Study Suggests

Diarrhea may be the first or only symptom some COVID-19 patients experience, according to the authors of a study.

The study, published in The American Journal of Gastroenterology, involved 206 patients at the Union Hospital, Tongji Medical College, in Wuhan, the Chinese city where the virus first emerged. The patients were classed as having mild COVID-19 cases as they didn't have shortness of breath or respiratory distress, and had a relatively high blood oxygen saturation level. The patients were sent to the facility despite their mild symptoms so they could be monitored and quarantined during the peak of the Wuhan outbreak.

The group included 48 who only had digestive symptoms such as diarrhea; 69 with digestive and respiratory symptoms; and 89 with only respiratory symptoms. On average, the patients, who lived in Wuhan, were aged 62, and 55.8 percent were female.

Of the 67 who had diarrhea, 19.4 percent had it as their first symptom of COVID-19, while the others developed it in the first 10 days after respiratory symptoms. The diarrhea lasted between one to 14 days. For 52.2 percent of patients, their stools were "watery," while for the others it was loose, not watery. Abdominal pain, meanwhile, was rare.

Some 62.4 percent of patients with digestive symptoms also had a fever. 73.1 percent who had diarrhea had a concurrent fever. Of those, 20.4 percent had an upset stomach before the fever; 10.2 percent after fever, and the others at the same time. Those who also felt sick and felt nauseous were more likely to have a fever than those with only lower digestive symptoms.

Patients who had digestive symptoms were more likely to seek care later than those with respiratory problems, the team found. And the period between the start of their symptoms and their bodies being rid of the virus was also longer. It was also more common for them to have the virus in their feces, at 73 percent compared with 14.3 percent in those with respiratory issues. The researchers tested the feces of 22 COVID-19 patients and found the RNA, or genetic material, of the new coronavirus in 12 samples.

Some COVID-19 patients may experience issues like diarrhea because the receptor that the virus binds to is expressed at almost 100-fold higher levels in the upper and lower gastrointestinal tract than the respiratory organs, the authors said.

As shown in the map by Statista below, the new coronavirus has spread to almost every country and territory in the world. According to Johns Hopkins University, almost 1 million cases have been confirmed worldwide, 47,522 people have died, and at least 195,929 have recovered.

coronavirus, map, covid-19, countries, world
A graphic provided by Statista shows the global spread of the new coronavirus as of early March 27. More than 921,000 people have been afflicted, over 192,000 of whom have recovered and over 46,200 of whom have died.

Most studies have focused on severely ill patients, but as 80 percent will have a mild form of the disease it is important to pinpoint their symptoms so those who aren't sick enough for hospitalization can self-quarantine, the authors said. Mild patients unwittingly spreading the virus "appears to be a major driver of the pandemic," they said.

"The longer disease course in patients with digestive symptoms might reflect a higher viral burden in these patients in comparison to those with only respiratory symptoms," the authors wrote.

The team highlighted the sample size of their paper was relatively small, and larger studies need to be conducted to explore digestive symptoms in mild COVID-19 patients further.

"This study does not directly confirm that viral particles in stool are infectious and capable of disease transmission, but our results offer more evidence that COVID-19 can present with digestive symptoms, that the virus is found in the stool of patients with diarrhea, and presents more indirect support of possible fecal transmission. Further research is vital to determine if COVID-19 can spread via the fecal-oral route," they said.

According to the CDC, common COVID-19 symptoms include a fever, cough, and shortness of breath.

The World Health Organization (WHO) states: "The risk of catching COVID-19 from the feces of an infected person appears to be low. While initial investigations suggest the virus may be present in feces in some cases, spread through this route is not a main feature of the outbreak.

"WHO is assessing ongoing research on the ways COVID-19 is spread and will continue to share new findings. Because this is a risk, however, it is another reason to clean hands regularly, after using the bathroom and before eating."

On Wednesday, the authors of a separate study on nine COVID-19 patients in Munich, published in the journal Nature did not find a replicating form of the virus in stool samples despite identifying high levels of viral RNA. Referring to the name of the new coronavirus, they said: "further studies should, therefore, address whether SARS-CoV-2 shed in stool is rendered non-infectious through contact with the gut environment," they wrote.

Co-author Brennan Spiegel, professor of medicine and public health at Cedars-Sinai, told Newsweek: "I think the main message is COVID-19 is not just cough.

"Clearly we're focused on cough and respiratory symptoms because those can be serious, those could cause mortality. So it's natural that our initial focus has been on patients arriving at hospital with shortness of breath, cough and pneumonia. And certainly that is a major manifestation of this disease.

"But we're starting to learn from our colleagues in China and around the world now that there's a large group of people who may not ever report for care, or at home with digestive symptoms—diarrhoea, nausea, vomiting, less so abdominal pain but that too, low appetite—who are struggling to determine if they have COVID-19 or not."

Spiegel stressed people should, as always, try to be as hygienic as possible when using the bathroom to prevent the spread of disease, including by closing the toilet lid when flushing to stop particles from being expelled into the air.

Brendan Wren, professor of microbial pathogenesis at the London School of Hygiene and Tropical Medicine who did not work on the study, told Newsweek: "There are many potential sources of gastrointestinal symptoms that may not be related to COVID-19. Indeed, the fact that patents got COVID-19 it may suggest poor hygiene and co-infections with other gastrointestinal pathogens.

"What is most interesting in this paper is the demonstration of direct shedding of the SARS-Cov-2 virus in the feces of these patients which may suggest alternative routes of transmission of COVID-19 apart from respiratory transfer."

Dr. Jurgen Haas, professor of viral genomics at the University of Edinburgh in Scotland, told Newsweek he and his colleagues reviewed the paper and concluded: "The implications are quite striking we think that this is an important study."

Haas explained: "It was known before that a certain percentage of COVID-19 patients have diarrhea and gastrointestinal symptoms, in addition to respiratory symptoms. We also know this from some of the other common cold coronaviruses and for example from Influenza.

"What is new is that a subgroup of COVID-19 patients with no or non-severe respiratory symptoms has a high likelihood to be positive for the SARS-CoV2 virus to be positive in the stool (and spread it via fecal-oral transmission). This subgroup has a later onset of the disease, but they contain and spread the virus for a longer period of time.

He said the study suggests the "gastrointestinal infection and fecal-oral spread are much more important in COVID-19 than we thought previously."

Pointing out the limitations, Haas said he and his epidemiologist colleagues who also reviewed the study said there were "minor flaws," such as an imbalance in the variables, for instance in gender, age, and symptoms which may bias some findings.

Haas said the work "obviously further supports the recommendation of frequent hand washing, using hand sanitizers and not touching the face with your hand. There are multiple other viruses (such as Noro-, Rota- and Adenoviruses) that can cause diarrhea, and SARS-CoV-2 is only one of those and most likely not as frequent as the others."

"However, the study suggests that individuals with diarrhea with or without respiratory systems which had been in contact with a confirmed COVID-19 case should definitely be tested for COVID-19," he said.

This article has been updated with comment from Professor Brennan Spiegel.

World Health Organization advice for avoiding spread of coronavirus disease (COVID-19)

Hygiene advice

  • Clean hands frequently with soap and water, or alcohol-based hand rub.
  • Wash hands after coughing or sneezing; when caring for the sick; before, during and after food preparation; before eating; after using the toilet; when hands are visibly dirty; and after handling animals or waste.
  • Maintain at least 1 meter (3 feet) distance from anyone who is coughing or sneezing.
  • Avoid touching your hands, nose and mouth. Do not spit in public.
  • Cover your mouth and nose with a tissue or bent elbow when coughing or sneezing. Discard the tissue immediately and clean your hands.

Medical advice

  • Avoid close contact with others if you have any symptoms.
  • Stay at home if you feel unwell, even with mild symptoms such as headache and runny nose, to avoid potential spread of the disease to medical facilities and other people.
  • If you develop serious symptoms (fever, cough, difficulty breathing) seek medical care early and contact local health authorities in advance.
  • Note any recent contact with others and travel details to provide to authorities who can trace and prevent spread of the disease.
  • Stay up to date on COVID-19 developments issued by health authorities and follow their guidance.

Mask and glove usage

  • Healthy individuals only need to wear a mask if taking care of a sick person.
  • Wear a mask if you are coughing or sneezing.
  • Masks are effective when used in combination with frequent hand cleaning.
  • Do not touch the mask while wearing it. Clean hands if you touch the mask.
  • Learn how to properly put on, remove and dispose of masks. Clean hands after disposing of the mask.
  • Do not reuse single-use masks.
  • Regularly washing bare hands is more effective against catching COVID-19 than wearing rubber gloves.
  • The COVID-19 virus can still be picked up on rubber gloves and transmitted by touching your face.