GENEVA, March 2 (Xinhua) -- COVID-19 is an infectious disease caused by a new coronavirus introduced to humans for the first time, tweeted the chief of World Health Organization (WHO) on Monday, adding that it can be contained with the right measures.

Noting that knowing and understanding the epidemic is the first step to defeating it, WHO Director-General Tedros Adhanom Ghebreyesus said on Twitter that "We are in unchartered territory with COVID-19. We have never before seen a respiratory pathogen that is capable of community transmission."

"It spreads from person to person mainly through the droplets produced when an infected person speaks, coughs or sneezes," explained Tedros.

The WHO chief reiterated that containment of COVID-19 is still feasible and must remain the top priority for all countries right now, though there is no one-size fits all approach.

"Our message to all countries is: this is not one-way street. We can push this coronavirus back," he reiterated. "Your actions now will determine the course of the COVID-19 outbreak in your country. There's no choice but to act now."

WHO is currently advising that all countries take actions on the "first case, first cluster, first evidence of community transmission."

Meanwhile, Tedros also deplored stigmatizing during the outbreak, which he said is "more dangerous than coronavirus itself."

"It is painful to witness the level of stigma we are seeing. We are not angels, we are human beings, but we can do the right thing," he said.