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What you should know about bird flu

The president is talking about quarantines. Others talk of millions dead. But what's the real threat?

By LISA GREENE
Published October 10, 2005

As if never-ending hurricanes and the constant threats of terrorism weren't enough, everyone from the president on down sounded warnings last week about an even more deadly danger: a global pandemic of bird flu that could kill millions of people.

President Bush is considering military quarantines. His top health official says the world isn't ready. The Senate has approved spending $3-billion to stockpile flu drugs.

Top infectious disease scientists say such attention is long overdue. A lethal strain of bird flu has been circulating in Asia for two years.

"If bird flu breaks out, Katrina is going to seem relatively mild," said Dr. John Sinnott, director of the Florida Infectious Disease Institute at the University of South Florida.

If doctors sound alarmist, it's because they look to history: The 1918 Spanish flu epidemic killed more than 40-million people worldwide.

Last week, scientists announced they had re-created the 1918 virus, and that it was a flu that started in birds and jumped to people.

But there's room for hope. So far, the deadly bird flu has spread from infected birds to people, not from person to person.

The world needs time, even just a few years, to stockpile antiviral drugs and develop a better vaccine, said Dr. Greg Poland, director of the Mayo Clinic Vaccine Research Group and a member of the advisory committee on vaccines for the federal Centers of Disease Control and Prevention.

"The one thing that makes me optimistic is that the current virus has not seemed to mutate in that direction," he said. "There is a race going on, and it's a race for human health."

In a strange way, the nightmares of Sept.11 and Hurricane Katrina may help the world prepare for flu, Poland said. He pointed to the Sept.11 commission findings: that leaders weren't prepared because they simply couldn't imagine something so awful could happen.

Now, we know it can.

There are many different kinds of influenza virus, named for different proteins on their surface. There are three known types of human flu, but many more are carried by wild birds. Most don't infect people, but the type H5N1 strain now in Asia can, and has already killed more than 65 people since 2003.

Influenza viruses circulate each year and kill thousands - an average of 36,000 in the United States alone. But they are kept in check by vaccines and the immunity that people have from being exposed before. In the case of bird flu, vaccine has not yet been manufactured and people have no immunity. What's more, it appears to be especially lethal.

"The mortality rate is 50 percent. That's what's suddenly grabbed people's attention," Poland said.

"The 1918 pandemic was wholesale destruction, and yet the mortality rate was only 2 percent. Literally, there would be no way to deal with it. We've seen what Katrina and Rita have done. There would be almost no words to explain."

"No one in the world is ready," said Mike Leavitt, U.S. Health and Human Services secretary, last week. Bush has been talking to vaccinemakers, and one company will start making the first bird flu vaccine, producing enough for a $100-million government stockpile.

Leavitt plans to meet this week with leaders in Southeast Asia, where the virus has been centered. He said last week that if a human outbreak occurs there, U.S. health officials will travel to the region to try to help treat people and isolate the virus.

It killed more people than any other disease outbreak in history. In The Great Influenza, the book that President Bush mentioned last week, author John M. Barry put it this way: "Influenza killed more people in a year than the Black Death of the Middle Ages killed in a century; it killed more people in 24 weeks than AIDS has killed in 24 years."

Nobody knows. Scientists have estimated that a bird flu pandemic could kill anywhere from 2-million to 150-million people.

Doctors worry that U.S. hospitals will quickly be overwhelmed. Expect a shortage of hospital beds, nurses and even ventilators for people who need help breathing, Sinnott said.

"Most hospitals are already operating very close to capacity," Sinnott said. "They wouldn't have the ventilators. They wouldn't have the antibiotics. They wouldn't have the antivirals. They wouldn't have the nurses."

Until the United States is better prepared, such shortages could create "an ethical nightmare" for doctors, he said. Would they give ventilators and medicines to those who arrived first? The sickest, because they need them most? Or those who are stronger and more likely to survive with such help?

Bush is talking about the possibility of using the military to enforce quarantines if bird flu arrives here. Widespread quarantines likely would be controversial, but Poland, who also is president of the Armed Forces Epidemiological Board, said rapid quarantines might be the only way to contain the virus if it arrives in a U.S. city, perhaps New York City, from overseas travelers. Still, he admits this would be hard to do.

"Human nature is such that, when there's fear of an outbreak, what people do is flee," Poland said. "But if a million people flee the area, and go to 10,000 different locations, you've made it impossible" to contain.

Several countries are trying to stockpile Tamiflu, the drug that best treats bird flu. But supplies remain limited.

Scientists now realize it infected cells deeper in the lungs. Instead of spreading widely through the body, it stayed in the lungs, where virus cells quickly multiplied, creating severe pneumonia that killed quickly as people's lungs basically drowned in extra fluid.

Wild birds carry the virus, but don't get sick. Chickens and other domestic birds often sicken and die. More than 100-million birds have died or been killed to try to stop the virus.

So far, most people who have gotten the disease have come in direct contact with infected birds. The virus is not spreading directly from person to person.

That's why scientists are so worried. Flu viruses are notoriously unstable, mutating and mixing with each other to produce new strains. The virus could mix with a human strain to gain the ability to spread among people. Scientists worry it also could mutate to gain that ability by itself, without mixing with a human strain, as it now appears the 1918 virus did.

Nobody knows. There has been one case where scientists believe bird flu was passed from a sick Thailand girl to her mother. Some scientists say that since bird flu hasn't yet mutated to a form that is more easily transmitted, there's reason to hope that it won't.

"I'm very worried about it, but not quite as worried as I was last year," Sinnott said.

Others hope that if it does mutate, it might also become less lethal as it becomes more easily transmitted. But Poland said both changes are a matter of chance.

"It could go either way," he said. "The problem is, as soon as you think you understand it, it changes. "

No. Other flu strains still could mutate to form a new strain to which people have little immunity.

No, and maybe. Today's flu shots won't protect against the current strain of bird flu. But if bird flu mixes with a human flu strain, so that a new strain is formed, it might provide some protection. Doctors advise getting flu shots anyway to protect against normal flu.

--Information from Drs. Poland and Sinnott, the CDC, Times wire services and "The Great Influenza' was used to compile this report.

[Last modified October 10, 2005, 12:11:45]