Sweeping travel bans have cascaded around the globe, walling off countries, keeping people inside their homes and slowing the engines of commerce to stem the coronavirus pandemic.
Markets collapsed with the growing realisation that there would be no fast end to the uncertainty.
After weeks downplaying the impact of the virus, US President Donald Trump's announcement of strict rules barring most Europeans from entry came as a shock across the Atlantic.
Within hours, even the European Union's passport-free travel came into question, with guards setting up in places that had been without borders for more than a decade and airports shut down.
US President Donald Trump announces the travel ban. Source: Getty Images
The head of the US Centers for Disease Control and Prevention, Robert Redfield, noted that the vast majority of new cases of the COVID-19 illness are linked to Europe.
Deaths in Italy topped 1,000, with more than 15,000 testing positive.
The virus detected three months ago in China has produced crippling outbreaks in Asia, Europe and the Middle East, ignited global financial panic and in the last week has led to dizzying developments erupt by the hour.
European soccer leagues, US basketball tournaments, school terms for millions of students, weddings, baptisms, funerals, nightlife, culture high and low - all fell by the wayside with a swiftness that was becoming increasingly difficult to grasp.
Britain Prime Minister Boris Johnson, whose country was spared the US travel ban, called the pandemic "the worst public health crisis for a generation" and he said: "many more families are going to lose loved ones before their time".
The illness edged closer to the world's power centres: C because his wife showed flu-like symptoms after her return from Britain, while the Brazilian president's communications director tested positive just days after travelling to meet with Mr Trump at Mar-a-Lago.
Ali Akbar Velayati, a top adviser to Iran's Supreme Leader Ayatollah Ali Khamenei, was under quarantine after reportedly being infected with the coronavirus.
Canada's Prime Minister Justin Trudeau and his wife Sophie Gregoire-Trudeau. Source: The Canadian Press
Developments in just one 24-hour period include an official designation of "pandemic" from the World Health Organization, the dramatic halt to much travel between the United States and 26 European countries, and infections being announced in rapid-fire pace by Hollywood celebrities, sports stars and political leaders as well as ordinary people on cruise ships.
Across the board, European markets closed on one of their worst days in history, unswayed by new stimulus measures from the European Central Bank to buy up 120 billion euros ($A211 billion) in bonds.
An early fall of 7.0 per cent on Wall Street triggered a trading halt amid the global sell-off but rose slightly after the Federal Reserve announced it would inject up to $US2 trillion into short-term lending markets.
More than 127,000 cases have been confirmed globally as of Friday morning.
Of these, approximately 68,000 have recovered and at least 4,628 have died.
The vast majority are in just four countries: China and South Korea - where new cases are declining - and Iran and Italy, where they are not.
The spread has slowed so much in China that the government sent a medical crew to Italy and offered surplus supplies to Iran and other countries in need.
More than 4,700 people have died worldwide.
In California, the governor advised officials to cancel any gatherings of more than 250 people, as well as any smaller meetings where people must be closer than two metres.
Congress shut the US Capitol and House and Senate office buildings to the public until 1 April and the White House cancelled tours.
Ireland, Denmark, Norway, Lithuania, Algeria and Slovakia joined the growing list of countries shutting down their school systems, and Europe's most successful football team, Real Madrid, put all its players into quarantine after one tested positive.
The Czech government said it would reimpose border checks and bar entry to people from 13 at-risk countries, including Britain and several in the European Union.
Slovakia closed its international airports and ground transport hubs.
Even remote Mount Everest closed for business. Chinese mountaineering officials cancelled spring climbs from their side of the mountain while on the other side in Nepal operators said cancellations were pouring in.
As the pandemic grips Europe and North America, it continues to ebb in China, where the first cases of COVID-19 emerged in December.
It reported a record low of just 15 new cases on Thursday. So far more than three-fourths of China's patients have recovered.
Among those newly testing positive were double Oscar winner Tom Hanks and his wife Rita Wilson in Australia; Juventus defender Daniele Rugani in Italy; Iran's senior vice president and two other cabinet ministers; and Spain's equality minister.
