Nigeria reported the first new coronavirus case in sub-Saharan Africa on Friday and a major global auto show was cancelled in a bid to stop contagion, as the deadly epidemic sent global stock markets and oil prices plunging.

The virus has proliferated around the globe over the past week, emerging in every continent except Antarctica, prompting many governments and businesses to try to stop people travelling or gathering in crowded places.

Switzerland became the latest country to announce drastic measures on Friday, saying all events with more than 1,000 participants would be suspended until March 15.

The ban forced the cancellation of the Geneva International Motor Show — a major item on the global auto industry calendar — that was due to start next week.

The virus has killed more than 2,800 people and infected over 83,000 worldwide — the vast majority in China — since it emerged apparently from an animal market in a central Chinese city in late December of last year.

The number of deaths and new infections has been tapering off in China, following unprecedented quarantine efforts locking down tens of millions of people in the worst-hit cities.

But infections elsewhere have started to surge, with Iran, Italy and South Korea becoming the major new hotspots and cases being confirmed in around 50 countries.

World Health Organisation chief Tedros Adhanom Ghebreyesus said on Thursday the world was at a "decisive point" and countries could still contain the epidemic if they "act aggressively now".

"No country should assume it won't get cases; that could be a fatal mistake, quite literally. This virus does not respect borders," Tedros said in Geneva.

The WHO has voiced particular concern about Africa's preparedness, warning that the continent's health care systems were ill-equipped to respond to a COVID-19 epidemic.

Cases had previously been reported in Egypt and Algeria, but not in the sub-Saharan region until Friday when Nigeria reported its first case: an Italian man who returned to densely populated Lagos this week.

Markets tank

Stock markets around the world have plummeted this week as it has become increasingly clear the virus will take a huge toll on the global economy.

European exchanges lost more than 3.0 per cent on Friday, tracking huge losses in Asia and the United States. Oil prices also dived four per cent to their lowest levels for more than a year, with Brent oil for April delivery sinking as low as $50.05 a barrel.

British Airways parent IAG said it was expecting "weaker demand" as a result of the virus, and no-frills carrier EasyJet said it would have to cancel some flights — particularly into and out of Italy.

Analysts have warned that China, the world's second largest economy, will see a major cut in growth this quarter as the country remains largely paralysed by quarantines and containment measures.

China hope

Still, signs in China offered hope that the outbreak could be contained.

China reported 44 more deaths on Friday, raising its toll to 2,788, with 327 new cases — the lowest daily figure for new infections in more than a month.

But the biggest concern for health officials is outside of China, with governments this week forced into increasingly drastic measures in an attempt to battle spiralling epidemics.

The biggest death toll outside China is in Iran, where 34 people have died.

As elsewhere, the virus has mostly killed the elderly or people who had other health conditions.

South Korea now has the most cases outside China, with more than 2,000 infections and 13 deaths.

The virus has had wide-ranging impact, even forcing K-pop megastars BTS to cancel four Seoul concerts due in April.

Schools shut

In Japan, Prime Minister Shinzo Abe said Thursday he would ask the country's schools to close, highlighting the growing fears of a major outbreak as Tokyo prepares to host the Summer Olympics.

Four people have died and more than 210 people been infected across Japan.

In virus-hit Hokkaido, governor Naomichi Suzuki declare a state of emergency until March 19 and asked residents to stay at home over the weekend.

Italy is Europe's epicentre with 650 cases and 17 deaths centred around cities in the north.

Wide-ranging measures to halt the spread of the virus have affected tens of millions of people in northern Italy, with schools closed and cultural and sporting events cancelled.

Belarus, Lithuania and New Zealand were the latest to report new cases, with links to Italy or Iran.

However, US President Donald Trump has downplayed the risk of a major epidemic in his country, and accused some media outlets of needlessly causing panic.

This is despite his government's own health officials telling communities to prepare for an epidemic.

Authorities in California said on Thursday they were monitoring 8,400 people for the virus, after officials confirmed a woman had contracted the disease without travelling to outbreak-hit regions.