Is it possible to have intestinal COVID-19 without having lung or nasal infection?

As of June 2020, the coronavirus pandemic has infected over 8 million people worldwide, with death toll at more than 400 000 people, and of these, over 3 million people are having active infection with 1% of them being in critical care. The numbers are harrowing to look at, and the fear that is being brought has prompted the government, scientists, researchers, doctors and civilians to work together to beat Covid-19 and eradicate it once and for all. Though ambitious, it is still a long way to go and we have to be vigilant at all times to avoid getting infected ourselves.

Test for coronavirus at current focuses on nasal and throat swabs due to its well-known route of transmission via respiratory droplets from coughing and sneezing. And the initial respiratory symptoms of Covid-19; cough, fever, and shortness of breath, also consolidates the validity of taking nose and throat swabs. But, lesser appreciated symptoms such as loss of appetite, diarrhoea, weight loss, nausea and vomiting are continuously being addressed by gastroenterologists to show the prevalence of intestinal Covid-19 infection. And this inevitably raises new questions, and of them, is it possible to have intestinal Covid-19 without having a lung or nasal infection?

The short answer is, yes. However, the study has been largely inconclusive. A small percentage of people infected with Covid-19 do manifest solely with the aforementioned gastrointestinal symptoms without respiratory and pneumonia-like symptoms. But does this mean that throat and nose swabs will test negative? This is unlikely. Large studies have shown that Covid-19 are primarily transmitted by droplets through respiratory mucosa and membranes, therefore, the nose and throat must harbour the viruses, and should in turn test positive. But there’s a catch. Patients with intestinal Covid infection will also test positive for their stool sample, and it persists even longer after the nose and throat swabs have shown negative results. Does this mean that a person is continuously shedding and transmitting the virus well after his perceived recovery and negative throat swabs through feco-oral route? This is a possibility and is being vigorously studied.

Whether it is a stool sample or secretions collected from the back of the throat, they are both tested using the same test, RT-PCR (real time polymerase chain reaction) which yields the most reliable results. RT-PCR is a complex procedure that uses the genetic materials of the coronavirus from collected samples, amplifies it and uses the amplified specimen to detect the presence or absence of the virus. The amplification process is crucial in this test because it allows the machines to detect a sample that has a very scarce amount of the viral genetic materials, hence effectively improving its accuracy in detecting the presence of viruses in the body.

A nose and throat swab, also referred to as a nasopharyngeal swab is easier and more straightforward to conduct. A health worker will use a long swab (6-inches) to collect specimens from the back of your nose or throat. The swab will be inserted from the nose with the head slightly tilted upwards, once the swab reaches the back of the nasal cavity, it is rotated several times to ensure adequate secretions are collected. The specimen will be sent to a lab with the capacity to run RT-PCR tests and results can be obtained within 1 to 7 days, depending on many factors.

A stool sample collection requires the patient to follow the doctor’s specific set of instructions in order to get the right amount and non-contaminated stool sample. The container will be sent to a lab for Covid-19 testing.

To date, researchers, doctors and scientists are continuously discovering something novel about the Covid-19, and it helps us in understanding the nature of the disease, how we can prevent its spread and eventually aid in developing the vaccine. And with that, we are still exploring the role and interaction between gastrointestinal system, respiratory system and Covid-19.