COVID-19 is a family of dangerous viruses that cause much illness from the cold to really more severe diseases such as respiratory syndromes. More severe diseases such as Acute Respiratory Syndrome SARS-CoV. Those viruses are a new version or strain that has not been seen and identified by humans.
COVID-19 are zoonotic, that means that they can be transmitted between people and animals. It is really contagious, this is why we call that the 2020 epidemic. Coronaviruses are circulating actually in animals and infecting many humans at this time.
This new coronavirus has never been identified before. The reason we call it COVID-19 is that it was currently found in 2019. This is not the same disease commonly found among humans.
Most of the time the Coronavirus will do only some mild illness, it can be mistaken for a common cold.
Anybody with the COVID-19 should be evaluated and put in quarantine until they are seen by medical personal. Call your health department from your country if you are unsure that you have the COVID-19.