People around the world have become increasingly closed off from one another amid sweeping travel bans as a viral pandemic unfolds and financial markets plunge.
The coronavirus was first detected three months ago in China and has been creeping across borders and producing outbreaks that have crippled areas.
The outbreak of Covid-19 has seen an official designation of “pandemic” from the World Health Organisation, a halt to much travel between the United States and 26 European countries, and infections among Hollywood stars, sports luminaries and political leaders.
It comes against a backdrop of plunging world economies that left not only Wall Street investors but people from all walks of life hurting.
“We will see more cases and things will get worse than they are right now,” said Dr Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases.
US President Donald Trump, who had downplayed the virus for days, suddenly struck a different tone, delivering a sombre Oval Office address announcing strict rules on travel from much of Europe to begin this weekend.
The State Department followed with an extraordinary warning to Americans to “reconsider travel abroad” too as cases across the US hit more than 1,300.
As the pandemic grips Europe and the US, 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 and was cautiously monitoring new arrivals who were returning with the virus from elsewhere.
More than three-quarters of China’s patients have recovered.
The formal declaration of a #COVID19 #pandemic does not change the fact that you can - and should - take these simple steps to protect yourself and your loved ones.— WHO Thailand (@WHOThailand) March 11, 2020
Watch and share this @WHO video!
Most people have only mild or moderate symptoms, such as a fever and cough, though symptoms can be severe, including pneumonia, especially in older adults and people with existing health problems.
Recovery for mild cases takes about two weeks, while more severe illness may take three to six weeks, the WHO says.
More than 126,000 people in over 110 countries have been infected.
But the WHO emphasised 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.
“We have called every day for countries to take urgent and aggressive action,” said the WHO’s leader, Tedros Adhanom Ghebreyesus.
“We have rung the alarm bell loud and clear.”
High-profile announcements of infections made the alarms even louder.
Double Oscar winner Tom Hanks said he and his wife Rita Wilson tested positive.
Australian officials said the couple are in a Queensland hospital and their close contacts would have to self-quarantine.
In Italy, football club Juventus said defender Daniele Rugani had tested positive.
Rugani sent a post on Twitter overnight in Italian.
Avrete letto la notizia e per questo ci tengo a tranquillizzare tutti coloro che si stanno preoccupando per me, sto bene.— Daniele Rugani (@DanieleRugani) March 12, 2020
Invito tutti a rispettare le regole, perchÃ© questo virus non fa distinzioni! Facciamolo per noi stessi, per i nostri cari e per chi ci circonda.#grazie pic.twitter.com/1QqewIKjie
“You’ll have read the news and that’s why I want to reassure everyone who is worrying about me. I’m OK. I want to remind everyone to respect the rules, because this virus doesn’t make distinctions! Let’s do it for ourselves, for those dear to us and for those around us,” he wrote.
In Iran, the senior vice president and two other cabinet ministers were reported to have been diagnosed with Covid-19.
Italy, already under unprecedented restrictions, tightened rules even more.
Italian Premier Giuseppe Conte announcing the closure of pubs, restaurants, hair salons, cafeterias and other businesses that can’t ensure a metre of space between workers and customers.
“In this moment, all the world is looking at us,” Mr Conte said, as the rules brought an eerie hush to places around Italy.
Asian shares plunged on Thursday, following a drop of 1,464 points of the Dow Jones Industrial Average, putting the index 20% below its record set last month and into fearsome territory Wall Street calls a “bear market”.
“There’s a real feeling that we don’t know where this ends,” said Brad McMillan, chief investment officer for Commonwealth Financial Network.