In humans, these viruses cause respiratory tract infections that can range from mild to lethal. Mild illnesses include some cases of the common cold (which is also caused by other viruses, predominantly rhinoviruses), while more lethal varieties can cause SARS, MERS, and COVID-19. Symptoms in other species vary: in chickens, they cause an upper respiratory tract disease, while in cows and pigs they cause diarrhea. There are as yet no vaccines or antiviral drugs to prevent or treat human coronavirus infections.
The disease appears to have originated from a Wuhan seafood market where wild animals, including marmots, birds, rabbits, bats and snakes, are traded illegally. Coronaviruses are known to jump from animals to humans, so it’s thought that the first people infected with the disease – a group primarily made up of stallholders from the seafood market – contracted it from contact with animals.
The hunt for the animal source of Covid-19 is still unknown, although there are some strong contenders. A team of virologists at the Wuhan Institute for Virology released a detailed paper showing that the new coronaviruses’ genetic makeup is 96 per cent identical to that of a coronavirus found in bats, while a study published on March 26 argues that genetic sequences of coronavirus in pangolins are between 88.5 and 92.4 per cent similar to the human virus. Some early cases of Covid-19, however, appear to have inflicted people with no link to the Wuhan market at all, suggesting that the initial route of human infection may pre-date the market cases.
The Wuhan market was shut down for inspection and cleaning on January 1, but by then it appears that Covid-19 was already starting to spread beyond the market itself. On January 21, the WHO Western Pacific office said the disease was also being transmitted between humans – evidence of which is apparent after medical staff became infected with the virus.
Covid-19 shares many of its symptoms with the flu or common cold, although there are certain symptoms common to flu and colds that are not usually seen in Covid-19. People with confirmed cases of Covid-19 rarely suffer from a runny nose, for instance.
The most common Covid-19 symptoms are a fever and a dry cough. Of 55,924 early Chinese cases of the disease, nearly 90 per cent of patients experienced a fever and just over two-thirds suffered with a dry cough. That’s why the UK government is advising anyone with a high temperature or a new, continuous cough to stay at home for seven days or, if they live with other people, for the entire household to isolate for 14 days from the first onset of symptoms.
Other Covid-19 symptoms are less common. Just under 40 per cent of people with the disease experience fatigue, while a third of people cough up sputum – a thick mucus from within the lungs. Other rarer symptoms include shortness of breath, muscle pain, sore throats, headaches or chills, loss of smell or taste. According to the WHO, symptoms tend to appear between five and six days after infection.
It’s too soon to tell how long the pandemic will continue. It depends on many things, including researchers’ work to learn more about the virus, their search for a treatment and a vaccine, and the public’s efforts to slow the spread.
More than 100 vaccine candidates are in various stages of development and testing. This process usually takes years. Researchers are speeding it up as much as they can, but it still might take 12 to 18 months to find a vaccine that works and is safe.
If you don’t feel well, stay home.
Even if you have mild symptoms like a headache and runny nose, stay in until you’re better. This lets doctors focus on people who are more seriously ill and protects health care workers and people you might meet along the way. You might hear this called self-quarantine. Try to stay in a separate room away from other people in your home. Use a separate bathroom if you can.
Call the doctor if you have trouble breathing
You need to get medical help as soon as possible. Calling ahead (rather than showing up) will let the doctor direct you to the proper place, which may not be your doctor’s office. If you don’t have a regular doctor, call your local board of health. They can tell you where to go for testing and treatment.
Follow your doctor’s advice and keep up with the news on COVID-19.
Between your doctor and health care authorities, you’ll get the care you need and information on how to prevent the virus from spreading.