Coronaviruses are a large group of viruses that are known to infect both humans and animals, and in humans cause respiratory illness that ranges from common colds to much more serious infections. The most well-known case of a coronavirus epidemic was Severe Acute Respiratory Syndrome (Sars), which, after first being detected in southern China in 2002, went on to affect 26 countries and resulted in more than 8,000 cases and 774 deaths. The number of people infected with Covid-19 has now well surpassed those hit with Sars.
While the cause of the current outbreak was initially unknown, on January 7 Chinese health authorities identified that it was caused by to a strain of coronavirus that hadn’t been encountered in humans before. Five days later the Chinese government shared the genetic sequence of the virus so that other countries could develop their own diagnostic kits. That virus is now called Sars-CoV-2.
Although symptoms of coronaviruses are often mild – the most common symptoms are a fever and dry cough – in some cases, they lead to more serious respiratory tract illness including pneumonia and bronchitis. These can be particularly dangerous in older patients, or people who have existing health conditions, and this appears to be the case with Covid-19. On February 5, Chinese health officials reported that two-thirds of the people who have died from Covid-19 were men, more than 80 per cent were over 60 years old and they typically had pre-existing health conditions such as diabetes or cardiovascular disease.