Federal officials declared a public health emergency Sunday as eight cases of swine flu were identified in New York and one was announced in Ohio, bringing the U.S. total of confirmed cases to 20.

In a briefing at the White House, the acting head of the Centers for Disease Control and Prevention, Dr. Richard Besser, warned Americans to prepare for a widespread outbreak, yet urged the public to remain calm.

Also Sunday, Homeland Security Secretary Janet Napolitano said the government would release a quarter of its 50-million-unit strategic reserve of antiviral medications, which combat the disease in infected patients, to states where outbreaks had occurred.

Canadian officials, meanwhile, said four cases had been confirmed in Nova Scotia and two in British Columbia, marking the first time that this particular strain had appeared north of the U.S. border. All six Canadian cases were mild, like those in the United States.


Several other countries have reported influenza-like illnesses that they suspect may be swine flu in travelers returning home from Mexico, but as of Sunday evening, none of them had been confirmed.

Nonetheless, many nations moved quickly to limit the disease’s spread, in many cases appearing to be near panic. Some, such as Poland and Venezuela, warned against traveling to the United States or Mexico. Others, such as Russia and Brazil, began screening some incoming international air travelers for signs of high fever.

China, Russia and Taiwan said they would quarantine returning passengers with flu symptoms.

In Mexico, Health Secretary Jose Angel Cordova said almost two dozen more deaths had occurred from influenza overnight, bringing the death total to 103. At least two of the new cases were confirmed as swine flu, for a total of 22 confirmed swine flu deaths. It is not clear how many of the others were caused by the virus.


Of the more than 1,600 suspected flu cases in that country, the Mexican government has said most are probably linked to other strains of the flu or respiratory diseases, not the new strain of swine flu.

On NBC’s “Meet the Press,” White House Press Secretary Robert Gibbs said swine flu was “serious enough to be a great concern to this White House and to this government.” He added that President Obama was receiving frequent updates on the situation.

“We are taking the proper precautions to address anything that happens,” Gibbs said. “It’s not a time to panic.”

Napolitano said the emergency declaration was a routine move to ensure that the government was prepared “in an environment where we really don’t know, ultimately, what the size or seriousness of this outbreak is going to be.”


It seemed certain, however, that the number of swine flu cases -- mild or otherwise -- would rise. “As we continue to look for cases, we are going to see a broader spectrum of disease,” Besser said. “We’re going to see more severe disease in this country.”

Because of the situation in Mexico, “I do feel that we will have deaths here,” Dr. Anne Schuchat of the Centers for Disease Control and Prevention said at a separate news conference. She’s the interim deputy director for science and public health programs.

Besser said the CDC had isolated the swine flu virus and prepared a “seed stock” for the manufacture of a vaccine but would not distribute it to pharmaceutical companies until the situation became more severe. Manufacture of a new vaccine will require months.

Public health officials cast the various moves as aggressive but precautionary, and they counseled calm.


The eight confirmed cases in New York involved students at St. Francis Preparatory School in Queens. City officials had said Saturday that the virus involved was probably swine flu, and that was confirmed overnight by researchers at the CDC. Some of those students had taken a spring break in Mexico.

Flu-like symptoms have been reported in some of the parents, but causes have not been confirmed.

Officials also tested children at a New York day-care center where illness had been reported, but those tests came back negative.

The new case in Ohio is a 9-year-old boy in Lorain County. He has a mild case of the disease and is recovering at home.


Previously announced cases included two in Texas, two in Kansas and seven in California’s Imperial and San Diego counties. All the cases were mild, and the victims have recovered.

The Nova Scotia Department of Health Promotion and Protection said Sunday that four cases had been confirmed in Windsor, Hants County, in eastern Canada. The four victims were students who had recently traveled to Mexico. None of them have been hospitalized.

Two teenage boys in British Columbia in western Canada were also confirmed to have swine flu. Both had mild cases, which were identified as swine flu only because their doctors heeded government calls to perform tests on flu victims who had traveled out of the country.

“This is moving fast,” Besser said, “but I want you to understand that we view this more as a marathon.”


The symptoms of swine flu are nearly identical to those of other influenza, including high fever, aches, coughing and congestion. It is spreading by human to human contact.

No cases of infection from pigs have been confirmed. And although Russia and some other countries have banned imports of pork from Mexico, there is absolutely no evidence that it can be transmitted by eating meat, said Dr. Keiji Fukuda, assistant director-general of the World Health Organization.

Several airlines said they would waive charges for changing tickets for passengers scheduled to travel to or through Mexico.

Health experts have noted that about 36,000 people die in the U.S. during a normal flu season, with deaths worldwide totaling 500,000 to 1 million annually. Officials suspect that many of the deaths in Mexico were, in fact, caused by seasonal influenza, which is believed to remain a greater threat than swine flu.


The principal difference with the new virus is that -- as with the 1918 Spanish flu pandemic -- it seems to be affecting primarily the young and healthy, rather than the children and elderly most severely afflicted by seasonal flu.

Besser and other officials at the news conference emphasized steps that the public could take to limit the spread of the disease: Wash hands frequently; stay home and don’t board airplanes if you feel sick; and keep sick children out of school.

Meanwhile, California and other affected states have requested CDC assistance in tracking the infections and have recommended increased testing of people with flu symptoms who have been traveling or who have severe cases.

California health authorities have also ordered enhanced veterinary activities to look for outbreaks in pigs.


Gibbs said it was too early to speculate about economic effects of an outbreak. And he dismissed reporters who asked whether the federal response was hampered by the fact that the Senate had not confirmed Obama’s nominee to lead the Department of Health and Human Services, Gov. Kathleen Sebelius of Kansas.

“It’s all hands on deck, and we’re doing fine,” Gibbs said. “I would say that we hope we have a new secretary shortly.”

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jtankersley@latimes.com


thomas.maugh@latimes.com

Noam Levey in the Washington bureau contributed to this report.

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(BEGIN TEXT OF INFOBOX)


Swine flu facts

WHAT IS IT?

Swine flu is a general term for flu viruses adapted to pigs. Swine flu can infect humans, most often from a pig to someone handling pigs. It can pass from human to human via coughing, sneezing or touching infected people or surfaces, then touching the mouth, nose or eyes.

SYMPTOMS


Symptoms are similar to regular flu: fever, fatigue, sore throat, cough, poor appetite, body aches and chills. Some people also have nausea, vomiting and diarrhea.

HOW DANGEROUS IS IT?

Experts don’t know how deadly swine flu is because they don’t know how many people have been infected. The World Health Organization says the overall mortality rate is 1% to 4%.

PREVENTION


Cover your mouth when you cough and sneeze. Use tissues and throw them in the trash. Wash your hands with soap and water. Use alcohol- based hand sanitizers. Avoid sick people. If you are sick, stay home. People who have been exposed can get a prescription for the antiviral drugs oseltamivir (Tamiflu) or zanamivir (Relenza).

-- Shari Roan