Fever and a dry cough are the most common symptoms of the coronavirus disease (Covid-19) .
The Sars-Cov-2 virus, which that causes Covid-19, enters the human body by attaching to receptors in the respiratory tract. Initially, the virus attacks the back of the throat and then trickles down to inflame the lungs. Covid-19 has afflicted over 471, 790 people across the globe and claimed more than 21,290 lives since last December. In India, the total number of Covid-19 positive cases stands at 649 and 13 reports have been reported to date.
Fever is the first sign of the disease and starts showing after an average five-day of the incubation period, showed an analysis of the disease progression in 191 hospitalised patients from central China’s Wuhan, the epicentre of the initial outbreak, in February. It found that 94% of patients developed a fever of 37.3 degrees Celsius or more, 79% had a cough, 23% reported fatigue, and 15% muscle pain.
How it spreads
During the first three days of the symptoms showing up, the virus uses a spike-like protein to bind with a receptor called angiotensin-converting enzyme 2 (ACE-2) found on the respiratory cells at the back of the throat, which leads to a dry cough.
Between day four and nine of the onset of the symptom, the virus starts attacking the lungs, causing laboured breathing and may lead to pneumonia, inflammation in the alveoli or lung sacs filled with fluid and pus.
“The current advice is to watch out for these initial symptoms – fever, dry cough, and breathing difficulties. Patients might experience a variety of symptoms including gastric symptoms such as diarrhoea, but these appear later in the course of the infection. It is important that we detect the cases early on to ensure that they don’t spread it to others,” said Dr Raj Kumar, director, Vallabhbhai Patel Chest Institute, Delhi.
Doctors from the United Kingdom have warned that a sudden loss of a sense of smell or taste could be a new marker of the Covid-19 disease.
Gastrointestinal signs
Hospitalised patients may also develop gastrointestinal symptoms, as around 5% may suffer from diarrhoea, and another 4% experience nausea and vomiting, according to a study conducted on 191 patients in Wuhan. A newer pre-print version of another study of 204 patients from central China’s Hubei province, whose capital is Wuhan, released on March 23 pegs the gastrointestinal symptoms as high as 50% of all the Covid-19 positive cases studied.
“In India, diarrhoea has been recorded in a few patients but it does not seem to be a predominant symptom. Predominant symptoms are fever, cough and shortness of breath. A sudden loss of a sense of smell or taste has not been recorded. But I cannot rule it out because that history is being taken,” said Dr Nivedita Gupta, a senior scientist with the Indian Council of Medical Research (ICMR), which is spearheading the Covid-19 diagnosis efforts.
Of the patients who experience gastrointestinal symptoms, about 79% complain of a lack of appetite, 34% diarrhoea, 4% vomiting, and 2% abdominal pain.
“It does look from the emerging data that more people have gut symptoms. This is not at all surprising as the ACE 2 receptor that the virus uses to enter the host cells are most highly expressed in the small intestine along with the respiratory tract. The numbers reported initially must have been lower because the patients would have been more critical due to severe respiratory symptoms, and doctors would be worried about tackling those complications,” said Dr Gagandeep Kang, director, Translational Health Science and Technology Institute.
So, should we be worried about diarrhoea? “When you have a viral illness, you tend to suffer from viral prodrome – fatigue, aches, loss of appetite etc. So watching out for diarrhoea does make sense, especially in a situation where you are out and about and can pass on the infection to others. If you have such symptoms, it is better to either isolate yourself or get tested,” said Kang.
The higher rates of gastrointestinal symptoms may lead to scientists to research more on whether they could be a mode of transmission, she added.
