A unique strain of swine flu is the suspected
killer of dozens of people in Mexico, where authorities closed
schools, museums, libraries and theaters in the capital on Friday
to try to contain an outbreak that has spurred concerns of a global
The worrisome new virus - which combines genetic material from
pigs, birds and humans in a way researchers have not seen before -
also sickened at least eight people in Texas and California, though
there have been no deaths in the U.S.
"We are very, very concerned," World Health Organization
spokesman Thomas Abraham said. "We have what appears to be a novel
virus and it has spread from human to human ... It's all hands on
deck at the moment."
The outbreak caused alarm in Mexico, where more than 1,000
people have been sickened. Residents of the capital donned surgical
masks and authorities ordered the most sweeping shutdown of public
gathering places in a quarter century.
President Felipe Calderon said his government only learned late
Thursday, with the help of international laboratories, what kind of
virus Mexico is faced with. "We are doing everything necessary,"
he said after meeting with his Cabinet to coordinate a response.
"We understand the seriousness of the problem."
The WHO was convening an expert panel to consider whether to
raise the pandemic alert level or issue travel advisories.
It might already be too late to contain the outbreak, a
prominent U.S. pandemic flu expert said late Friday.
Given how quickly flu can spread around the globe, if these are
the first signs of a pandemic, then there are probably cases
incubating around the world already, said Dr. Michael Osterholm at
the University of Minnesota.
In Mexico City, "literally hundreds and thousands of travelers
come in and out every day," Osterholm said. "You'd have to
believe there's been more unrecognized transmission that's
There is no vaccine that specifically protects against swine
flu, and it was unclear how much protection current human flu
vaccines might offer. A "seed stock" genetically matched to the
new swine flu virus has been created by the U.S. Centers for
Disease Control, said Dr. Richard Besser, the agency's acting
director. If the government decides vaccine production is
necessary, manufacturers would need that stock to get started.
Authorities in Mexico urged people to avoid hospitals unless
they had a medical emergency, since hospitals are centers of
infection. They also said Mexicans should refrain from customary
greetings such as shaking hands or kissing cheeks. At Mexico City's
international airport, passengers were questioned to try to prevent
anyone with flu symptoms from boarding airplanes and spreading the
Epidemiologists are particularly concerned because the only
fatalities so far were in young people and adults.
The eight U.S. victims recovered from symptoms that were like
those of the regular flu, mostly fever, cough and sore throat,
though some also experienced vomiting and diarrhea.
U.S. health officials announced an outbreak notice to travelers,
urging caution and frequent handwashing, but stopping short of
telling Americans to avoid Mexico.
Mexico's Health Secretary Jose Angel Cordoba said 68 people have
died of flu and the new swine flu strain had been confirmed in 20
of those deaths. At least 1,004 people nationwide were sick from
the suspected flu, he said.
The geographical spread of the outbreaks also concerned the WHO
- while 13 of the 20 deaths were in Mexico City, the rest were
spread across Mexico - four in central San Luis Potosi, two up near
the U.S. border in Baja California, and one in southern Oaxaca
Scientists have long been concerned that a new flu virus could
launch a worldwide pandemic of a killer disease. A new virus could
evolve when different flu viruses infect a pig, a person or a bird,
mingling their genetic material. The resulting hybrid could spread
quickly because people would have no natural defenses against it.
Still, flu experts were concerned but not alarmed about the
"We've seen swine influenza in humans over the past several
years, and in most cases, it's come from direct pig contact. This
seems to be different," said Dr. Arnold Monto, a flu expert with
the University of Michigan.
"I think we need to be careful and not apprehensive, but
certainly paying attention to new developments as they proceed."
The CDC says two flu drugs, Tamiflu and Relenza, seem effective
against the new strain. Roche, the maker of Tamiflu, said the
company is prepared to immediately deploy a stockpile of the drug
Both drugs must be taken early, within a few days of the onset
of symptoms, to be most effective.
Cordoba said Mexico has enough Tamiflu to treat 1 million
people, but the medicine will be strictly controlled and handed out
only by doctors.
Mexico's government had maintained until late Thursday that
there was nothing unusual about the flu cases, although this year's
flu season had been worse and longer than past years.
The sudden turnaround by public health officials angered many
"They could have stopped it in time," said Araceli Cruz, 24, a
university student who emerged from the subway wearing a surgical
mask. "Now they've let it spread to other people."
The city was handing out free surgical masks to passengers on
buses and the subway system, which carries 5 million people each
day. Government workers were ordered to wear the masks, and
authorities urged residents to stay home from work if they felt
Closing schools across Mexico's capital of 20 million kept 6.1
million students home, as well as thousands of university students.
All state and city-run cultural activities were suspended,
including libraries, state-run theaters, and at least 14 museums.
Private athletic clubs closed down and soccer leagues were
considering canceling weekend games.
The closures were the first citywide shutdown of public
gathering places since thousands died in the devastating 1985
Mexico's response brought to mind other major outbreaks, such as
when SARS hit Asia. At its peak in 2003, Beijing shuttered schools,
cinemas and restaurants, and thousands of people were quarantined
In March 2008, Hong Kong ordered more than a half-million
students to stay home for two weeks because of a flu outbreak. It
was the first such closure in Hong Kong since the outbreak of SARS,
or severe acute respiratory syndrome.
"It's great they are taking precautions," said Lillian Molina,
a teacher at the Montessori's World preschool in Mexico City, who
scrubbed down empty classrooms with Clorox, soap and Lysol between
fielding calls from worried parents.
U.S. health officials said the outbreak is not yet a reason for
alarm in the United States. The five people sickened in California
and three in Texas have all recovered.
It's unclear how the eight, who became ill between late March
and mid-April, contracted the virus because none were in contact
with pigs, which is how people usually catch swine flu. And only a
few were in contact with each other.
CDC officials described the virus as having a unique combination
of gene segments not seen before in people or pigs. The bug
contains human virus, avian virus from North America and pig
viruses from North America, Europe and Asia. It may be completely
new, or it may have been around for a while and was only detected
now through improved testing and surveillance, CDC officials said.
The most notorious flu pandemic is thought to have killed at
least 40 million people worldwide in 1918-19. Two other, less
deadly flu pandemics struck in 1957 and 1968.
Swine Flu Outbreak
A unique strain of swine flu is the suspected