Coronaviruses are a large group of viruses that are common among animals and can be transmitted from animals to humans, according to the US Centers for Disease Control and Prevention.
Coronavirus disease (COVID-19) is a new strain that was discovered in 2019 and has not been previously identified in humans. They are zoonotic, meaning they are transmitted between animals and people.
The COVID-19 Coronavirus, a cousin of the SARS virus, has infected hundreds since the outbreak began in Wuhan, China, in December. Scientist Leo Poon, who first decoded the virus, told CNN that he thinks it likely started in an animal and spread to humans.
The viruses can make people sick, usually with a mild to moderate upper respiratory tract illness, similar to a common cold. Coronavirus symptoms include a runny nose, cough, sore throat, possibly a headache and maybe a fever, which can last for a couple of days.
For those with a weakened immune system, the elderly and the very young, there's a chance the virus could cause a lower, and much more serious, respiratory tract illness like pneumonia or bronchitis.
The handful of human coronaviruses that are known to be deadly include the Middle East respiratory syndrome, also known as the MERS virus, which was first reported in the Middle East in 2012 and also causes respiratory problems, but those symptoms are much more severe.
The other coronavirus that can cause more severe symptoms is the severe acute respiratory syndrome, also known as SARS. First identified in the Guangdong province in southern China, according to the WHO, it causes respiratory problems but can also cause diarrhoea, fatigue, shortness of breath, respiratory distress and kidney failure.
The COVID-19 Coronavirus is currently thought to be milder than SARS and MERS and takes longer to develop symptoms. Patients to date have typically experienced a mild cough for a week followed by shortness of breath, causing them to visit the hospital. In more severe cases, the infection can cause pneumonia, severe acute respiratory syndrome, kidney failure and even death. So far, around 15% to 20% of cases have become severe.
Standard recommendations to prevent infection spread include regular hand washing, covering mouth and nose when coughing and sneezing, thoroughly cooking meat and eggs. Avoid close contact with anyone showing symptoms of respiratory illness such as coughing and sneezing.
Officials do not yet know what animal may have caused the current outbreak but depending on how virulent the virus is, a cough, sneeze or handshake could cause exposure. The virus can also be transmitted by touching something an infected person has touched and then touching your mouth, nose or eyes.
Many countries have closed their borders to nationals of infected countries to avoid close contact. Schools have been shut down and public gatherings banned in several countries to minimize the spread of the virus which has crossed countries and continents.