WHO says the most common symptoms of Covid-19 are fever, cough and fatigue. With nearly 900,000 people infected as yet, a growing pool of data suggests there could be more markers of the diease.
A loss of smell and taste and digestive disruptions could be symptoms of Covid-19, according to multiple studies.
Clinicians across the world are focusing on the key symptoms as defined by the World Health Organization as fever, cough and breathing distress to diagnose the coronavirus disease. Loss of smell and taste are also common symptoms of the flu and many other respiratory diseases.
But as the number of cases increases to nearly 900,000 and data accumulates, anosmia, the loss of smell; hyposmia, a reduced sense of smell; dysgeusia, the distortion of the sense of taste, and gastrointestinal issues are being reported more and more by Covid-19 patients, according to studies and anecdotal evidence.
"Anecdotal evidence is rapidly accumulating from sites around the world that anosmia and dysgeusia are significant symptoms associated with the Covid-19 pandemic. Anosmia, in particular, has been seen in patients ultimately testing positive for the coronavirus with no other symptoms," according to the American Academy of Otolaryngology-Head and Neck Surgery reported.
"These symptoms should be added to the list of screening tools for possible Covid-19 infection," it said.
A new marker of Covid-19?
In a newsletter, Claire Hopkins, president of the British Rhinological Society, and Nirmal Kumar, president of ENT UK, said more than two in three confirmed cases of coronavirus in Germany reported a loss of smell.
In South Korea, 30 percent of patients who tested positive for the virus had anosmia as their main symptom.
"Iran has reported a sudden increase in cases of isolated anosmia, and many colleagues from the US, France, and northern Italy have the same experience," the newsletter said.
The report also mentions anecdotal evidence that a patient can be generally asymptomatic, only presenting anosmia, and still test positive for the virus.
However, patients with just anosmia are often not tested or asked to self-isolate as this symptom is not yet recognised as a sign of coronavirus.
This is what Coronavirus symptoms look like pic.twitter.com/qhOqQQFOZM— Science is Amazing (@AMAZINGSClENCE) March 26, 2020
Knowledge of symptoms can help flatten the curve
Countries around the world are seeking to "flatten the curve" which represents growth in infections by implementing social distancing and other containment measures. If successful, it allows hospitals to function without being overwhelmed by an influx of patients.
The number of confirmed Covid-19 cases around the world is now nearing 900,000, with more than 38,000 deaths. The toll on health systems is staggering, with medical professionals under enormous strain.
The SARS-Cov-2 virus which causes Covod-19 is highly contagious. Each person with coronavirus disease can infect 2.3 others.
Combine that with the fact that people can walk around for up to two weeks before the infection becomes symptomatic and that some people have no symptoms despite being infected and you have a very serious pandemic.
Most patients who contract coronavirus disease develop only mild symptoms, for example, fever and coughing, and recover after about two weeks.
Many of them don't even realise they have coronavirus disease and carry on with minimal social distancing measures.
Older adults and people with underlying health problems seem to be the most vulnerable to a more severe form of Covid-19, which can result in pneumonia and death.
Awareness of early symptoms could help people take the necessary measures to prevent contagion.
There is also some evidence that the disease has early gastrointestinal symptoms, according to a new report from physicians at Shanghai Jiao Tong University.
"Current studies reveal that respiratory symptoms of Covid-19 such as fever, dry cough, even dyspnea [difficult or laboured breathing] represents the most common manifestations at visit similar to severe acute respiratory syndrome (SARS) in 2003 and Middle East Respiratory Syndrome (MERS) in 2012, which is firmly indicative of droplet transmission and contact transmission," the report says.
"However, the incidence of less common features like diarrhoea, nausea, vomiting and abdominal discomfort varies significantly among different study populations, along with an early and mild onset frequently followed by typical respiratory symptoms."
The report calls for more work on on the initial digestive symptoms of Covid-19 "for early detection, early diagnosis, early isolation and early intervention."
Early data from Wuhan also pointed at gastrointestinal symptoms preceding fever in Covid-19 patients.
Clinicians urged to recognise digestive symptoms
Coronavirus diease could cause vomiting and diarrhoea, along with abdominal pain, during early stages of infection, an American Journal of Gastroenterology said.
About 204 patients were studied for this report that indicates a small minority of patients (7/204) had only digestive symptoms without any respiratory symptoms, through 45 percent had both respiratory and digestive symptoms.
"Clinicians should recognise that digestive symptoms, such as diarrhea, are common among the presenting features of Covid-19, and that the index of suspicion may need to be raised earlier in at-risk patients presenting with digestive symptoms. However, further large sample studies are needed to confirm these findings," the report said.
Covid-19 transmission from human excrement
As coronavirus pandemic spreads through countries which struggle with droughts, water shortages, poor sewage infrastructure and a shortage of indoor toilets, the transmission of the virus via the faecal-oral route could have deadly consequences.
Investigators from China's Guangdong province examined the viral RNA in faeces from 71 patients with confirmed Covid-19 between February 1 and February 14.
The authors of this report suggested faecal-oral transmission could be a path for viral spread.
"Preventing faecal-oral transmission should be taken into consideration to control the spread of the virus," the authors wrote.