Five things to know about coronaviruses

Here are five things to know about coronaviruses:

1. Coronaviruses are named for their appearance. "Corona" is Latin for "crown". When viewed under a microscope, these viruses have bits sticking out from them that look a bit like a royal crown. 
2. Coronaviruses are quite common in humans. They infect the upper respiratory tract, and most are not deadly. Almost everyone will be infected by one or other type of these viruses in their lives.
3. Some coronaviruses infect animals, and not humans. A few start off infecting only animals and then mutate to be able to infect humans.
   
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   Only seven coronaviruses so far have done this. 2019-nCoV is believed to have come from bats and snakes. Sars came from civet cats, and Mers from camels. There are several known coronaviruses which are circulating in animals that have not yet infected humans.
4. Coronaviruses cause diarrhoea and respiratory tract infections in animals like cows and pigs. In people, they can mimic the common cold, but may also lead to pneumonia. The virus spreads among humans when they cough or sneeze.
5. There is no specific treatment or antiviral drug for coronaviruses. The best way to prevent catching one is by practising good hygiene.