is clear the pathogen is nowhere near contained.

Tomorrow, the World Health Organization will determine whether to declare this outbreak

a global public health emergency.

William Brangham has the latest.

WILLIAM BRANGHAM: As this coronavirus continues its breakneck spread across China, the global

aviation industry is starting to isolate the country.

At least nine major airlines are limiting or stopping flights to and from mainland China,

including British Airways, United, American and Lufthansa.

The United States and many other nations are also warning their citizens to avoid any nonessential

travel to the country.

Dr. Trish Perl is chief of infectious diseases at the University of Texas Southwestern Medical

Center.

DR. TRISH PERL, University of Texas Southwestern Medical Center: This kind of dynamism, I have

certainly not witnessed in my career. So, I would say that it is really very, very dramatic.

WILLIAM BRANGHAM: Chinese officials are still struggling with the pace of the this outbreak.

Hospitals here in Wuhan, the epicenter city, have been overrun and understaffed for over

a week now.

YANZHONG HUANG, Council on Foreign Relations: Now even the Chinese health authorities admit

that this is -- in terms of contagiousness, is much stronger than we thought.

WILLIAM BRANGHAM: Yanzhong Huang is a public health researcher at the Council on Foreign

Relations.

YANZHONG HUANG: So, scientists are saying that it is -- that the cases are going to

continue to increase.

WILLIAM BRANGHAM: To stop people leaving affected areas, the government has shut down an unprecedented

number of railways and roads, effectively locking down more than 35 million people.

But cases have now appeared in over 30 different Chinese provinces, across a huge swathe of

the country. Public health experts say the official death toll will most certainly rise.

DR. TRISH PERL: The fact that we have however many mortality we have -- or how many deaths

we have today, that may not reflect the people who are still in care, not doing well, ultimately

who will die.

WILLIAM BRANGHAM: Dr. Perl and others also say, the speed and efficiency of this virus'

spread mean some of the containment efforts might have come too late.

DR. TRISH PERL: Overall what they're doing is reasonable, as best I can tell. I mean,

I think you have to understand that we're getting bits and pieces of what that response

is.

But I do wonder if a lot of this response actually happened, in a way, after the cat

was out of the bag.

WILLIAM BRANGHAM: On top of that, shortages of protective gear and diagnostic kits make

treating and tracking the virus especially hard.

YANZHONG HUANG: So, everywhere, we have seen this shortage, including in Shanghai, actually.

The people -- there's video clips showing that people actually were fighting for, like,

the facial masks in a store.

WILLIAM BRANGHAM: As the lockdown has grown, anger is growing as well. Protesters in Hong

Kong set fire to a public housing complex, furious that a proposed quarantine site was

going to be put near their homes.

Globally, there are fewer than 100 official cases outside of China. It's in at least eight

other Asian nations, as well as Australia, France, Germany, Canada, and the U.S. The

U.S. has just a handful of cases, and no known deaths.

Just for perspective, last year, the flu virus is estimated to have taken the lives of more

than 30,000 Americans.

Dr. Robert Redfield, the head of the Centers for Disease Control and Prevention, tried

to tamp down fears over this new virus.

DR. ROBERT REDFIELD, Director, Centers for Disease Control and Prevention: Right now,

there is no spread of this virus in our communities here at home.

This is why our current assessment is that the immediate health risk of this new virus

to the general public is low in our nation. The coming days and weeks are likely to bring

more confirmed cases here and around the world, including the possibility of some person-to-person

spread.

WILLIAM BRANGHAM: Those nearly 200 Americans who were evacuated from Wuhan have been screened

three times already. They will now spend three days in quarantine, where they will be watched

for signs of the virus.

For the "PBS NewsHour," I'm William Brangham.