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Δευτέρα, 27 Απριλίου 2009

The new strain of H1N1 influenza

UPDATE 1-U.S. acts swiftly to contain swine flu outbreak

U.S. Human Cases of Swine Flu Infection
State # of laboratory
confirmed cases
California 7 cases
Kansas 2 cases
New York City 8 cases
Ohio 1 case
Texas 2 cases
TOTAL COUNT 20 cases
International Human Cases of Swine Flu Infection
See: World Health OrganizationExternal Web Site Policy.
As of April 26, 2009 9:00 AM ET

Sun Apr 26, 2009 5:12pm EDT

* US to release 25 percent of anti-viral stockpile

* Health chief recommends planning for school closures

* Too early to determine impact on economy (Updates to add information from CDC briefing)

By Ross Colvin

WASHINGTON, April 26 (Reuters) - The United States declared a public health emergency on Sunday because of an outbreak of swine flu that has been diagnosed in 20 people in this country -- the same strain suspected of killing 81 people in Mexico.

The outbreak is yet another distraction for President Barack Obama as he focuses on rescuing the economy from its worst crisis in decades. His administration will also be mindful of the damage to former President George W. Bush over his government's inept handling of Hurricane Katrina in 2005.

"At this point, a top priority is to ensure that communication is robust and that medical surveillance efforts are fully activated," John Brennan, assistant to the president for Homeland Security, told a White House briefing.

Dr Anne Schuchat of the Centers for Disease Control and Prevention told a separate briefing she feared that some people would die in the United States as the virus spread.

Health and Homeland Security officials announced steps to release some of the U.S. stockpiles of the anti-flu drugs Tamiflu and Relenza. They recommended that local authorities plan for possible school closures and that anyone with symptoms stay at home to reduce the possibility of transmission.

White House spokesman Robert Gibbs said it was too early to say what impact the outbreak could have on efforts to get the economy back on its feet. Spiraling healthcare costs are already a huge drain on the economy.

Homeland Security Secretary Janet Napolitano said the declaration of the public health emergency was necessary to free federal, state and local agencies' resources and authorize the release of funds to buy more antivirals.

"This is standard operating procedure," Napolitano stressed, adding that similar declarations had been issued in the past to help states cope with flooding or hurricanes.


The CDC confirmed 20 cases of swine flu in the United States and said all the patients had recovered and only one person had to be hospitalized. Officials said they were not testing air travelers from Mexico for the virus.

The CDC is preparing a "yellow card" for travelers explaining the flu symptoms and what precautions to take, Schuchat said. U.S. health officials are stressing frequent hand washing as the first line of defense against the virus.

Tests so far show that the H1N1 component of the seasonal flu vaccine does not protect against the new H1N1 swine flu strain, Schuchat said. It could take several months to develop a vaccine for the new virus, she added.

The virus in the U.S. cases appeared to be the same strain as the one that has killed scores in Mexico, CDC acting Director Dr Richard Besser said, although it was not yet clear why it had not proven as deadly in the United States. Health officials from the United States and Canada were now in Mexico to try to answer this "critical question," he said.

"We expect to see more cases of swine flu. As we continue to look for cases, we expect that we will find them," Besser said.

Napolitano said the United States would release 25 percent of the 50 million anti-flu drugs from the strategic national stockpile. The Department of Defense has also bought 7 million courses of Tamiflu for defense personnel, she said.

Tamiflu, a pill made by Roche AG ROG.X and Gilead Sciences Inc (GILD.O: Quote, Profile, Research, Stock Buzz), and GlaxoSmithKline's (GSK.L: Quote, Profile, Research, Stock Buzz) (GSK.N: Quote, Profile, Research, Stock Buzz) and Biota's (BTA.AX: Quote, Profile, Research, Stock Buzz) Relenza, an inhaled drug, can treat influenza if given quickly. They have been shown to work against this new flu strain.

Gibbs said Obama, who recently returned from a trip to Mexico, had shown no symptoms of the virus and had therefore not been tested. (Additional reporting by Kim Dixon, Donna Smith and Maggie Fox; editing by Eric Beech)

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Swine flu cases raise more questions than answers

Sun Apr 26, 2009 4:10pm EDT

By Maggie Fox, Health and Science Editor - Analysis

WASHINGTON (Reuters) - How widespread is this new swine flu that has killed as many as 81 people in Mexico? How can a swine flu be infecting people? Why has it killed some people and caused only mild symptoms in others?

The new strain of H1N1 influenza is behaving just as public health experts expect it to -- that is, unpredictably.

"It's very hard to predict exactly," Dr. Anne Schuchat of the U.S. Centers for Disease Control and Prevention told reporters in a conference call. "We all need to all be prepared for change."

Within hours on Sunday, officials learned of new cases across the United States and in Canada, for a total of 26, in addition to more than 1,300 suspected cases in Mexico.

Influenza can spread quietly, and people who are infected can spread the virus before they even start showing symptoms. One of the biggest problems with flu is that it causes flu-like symptoms -- just like dozens of other viruses and bacteria do.

Fever, headache, muscle aches, dry cough, extreme tiredness -- all these can be caused by numerous other infections from the rhinoviruses that cause the common cold to the less-known but also common adenoviruses.

"The syndrome that we are hearing about in Mexico is relatively non-specific," Schuchat noted. "There are many different causes of respiratory illnesses."

And people die of these common infections every day. Even during the height of the flu season, only 10 percent or less of deaths from "influenza-like illness" are ever confirmed to be influenza.

So tracking it is difficult.

Health officials all over the world are now testing people with influenza-like symptoms for the new strain of swine flu. It requires DNA tests because it is an influenza A virus -- like two of the strains now causing very common seasonal flu. It is also an H1N1 virus -- one of the seasonal strains.


Not until the DNA is sequenced does it become clear whether a person with influenza has this new and unusual strain of swine flu.

"It could be all over the place and they just haven't tested for it," said Mike Osterholm, a former Minnesota state health official who is now director of the Minnesota-based Center for Infectious Disease Research and Policy.

It already has turned up in Mexico, Canada and the United States, and among people who have nothing else apparent in common. That suggests the connection is an as-yet unseen chain of human infections.

"It is clear that this is widespread. And that is why we have let you know that we cannot contain the spread of this virus," Schuchat said.

This new strain is just what flu experts have worried about. It has DNA from four different strains of flu. While genetically it most closely resembles a swine H1N1 virus, it contains avian flu and human flu sequences as well.

While most cases in the United States, Canada and Mexico have been mild, it has killed up to 81 people in Mexico, including some young adults. This is disturbing because flu usually kills the very young, the very old and those with other underlying conditions.

"It may look different because we don't have good enough information. It may look different because the virus is different," Schuchat said.

Acting CDC director Richard Besser said this virus could itself disappear and reappear. "It's very hard to say," he told a White House briefing on Sunday. "We are nearing the end of the season in which flu viruses tend to transmit easily."

Besser said he would expect the number of cases to decline in the northern hemisphere's summer. Other pandemics have come in waves months apart and Besser said this virus could do that.

Pandemics hit in 1918 -- killing anywhere between 40 million and 100 million people globally -- and in 1957 and 1968. The 1968 pandemic was relatively mild, with 1 million deaths -- perhaps because the case, an H3N2 virus, was similar to the H3N2 that caused the 1957 pandemic and people had some immunity.

H1N1 has been around since the 1918 pandemic, in various forms but no one knows if this strain is different enough to cause widespread and severe disease. Health experts say the world is overdue for another pandemic but have stressed that no one can predict which strain would cause the next one.

(Editing by Philip Barbara)

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