President Bush said Tuesday that the possibility of an avian flu pandemic is among the reasons he wants Congress to give him the power to use the nation's military in law enforcement roles in the United States.
Such an deadly event would raise difficult questions, such as how a quarantine might be enforced, he said.
People who catch the worst strain of avian flu can die of viral pneumonia and acute respiratory distress, according to mayoclinic.com.
The disease has killed tens of millions of birds in Asia.
Last week, the U.N.'s health agency, the World Health Organization, sought to ease fears that the disease could kill as many as 150 million people worldwide.
The consequences of an outbreak in the United States need to be addressed before catastrophe strikes, Bush said.
Should avian flu mutate and gain the ability to spread easily from human to human, world leaders and scientists would need rapid access to accurate information to be able to stem its spread, he said.
Bush said he has spoken with Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, about work toward a vaccine, but that means of prevention remains a distant hope.
Absent an effective vaccine, public health officials likely would try to stem the disease's spread by isolating people who had been exposed to it. Such a move could require the military, he said.
The Posse Comitatus Act of 1878 bans the military from participating in police-type activity on U.S. soil.
Bush began discussing the possibility of changing the law last month, in the aftermath of the government's sluggish response to civil unrest following Hurricane Katrina.
The World Health Organization has reported 116 cases of avian flu in humans, all of them in Asia. More than half of them have been fatal, it said.
On Thursday, the Senate added $4 billion to a Pentagon spending bill to head off the threat of an outbreak of avian flu among humans. The bulk of the money -- $3 billion -- would be used to stockpile Tamiflu, an antiviral drug that has proved effective against the H5N1 virus -- the strain blamed for six deaths in Indonesia last week.
U.S. health agencies have about 2 million doses of Tamiflu, enough to treat about 1 percent of the population. The money added by the Senate would build that stockpile to cover about 50 percent of the population, CNN reported.