The OECD has warned the coronavirus is the gravest threat to the global economy since the financial crisis - as global markets saw fresh volatility in response to the outbreak..
The Paris-based international body slashed its already-weak outlook for world GDP growth and said that if not contained soon the virus could tip a number of economies into recession.
It came as global markets struggled to rebound following last week's sharp fall in response to the outbreak.
London's leading share index was up to 3% higher - more than 190 points - in early trading but later lost most of those gains. It was about 25 points, or 0.4%, up in late morning deals.
Markets in Germany and France also rose sharply on opening - following a rally for Asian shares, particularly in China - but later turned negative.
In an assessment of the impact of the crisis published on Monday, the Organisation for Economic Cooperation and Development (OECD) said the virus was already causing economic disruption.
It said that even in a "best case" scenario of limited outbreaks outside China, there would be a "sharp slowdown" in world growth for the first half of this year as supply chains and commodities are hit, tourism drops, and confidence falters.