CNET también está disponible en español.

Ir a español

Don't show this again

A bird flu resource guide

We could be just a mutation away from a deadly superflu, but many questions remain. Here's a reality check.

Sci-Tech
If the avian influenza slowly spreading from Asia to Europe turns into a global pandemic, as many fear, few will be able to say there was no warning.

World health experts have been alarmed by this new, deadly strain of bird flu since it killed more than 30 people in Thailand and Vietnam last year. And television outlets ranging from PBS to local television stations have weighed in on the chances of a bird flu outbreak in the United States.

Click to go to

On Tuesday, President Bush called on Congress to spend $7.1 billion on preparedness for a pandemic, which could be brought on by a mutated strain of bird flu (technically, the H5N1 virus). Experts have warned that in such an event millions of people worldwide could be killed.

To health experts, the proposal seemed long overdue. To the public, it was a double-edged sword, offering a sense of relief that the government was acting to protect the country, but also stoking fears that a superflu is on its way.

Nevertheless, no one really knows if the latter is really true.

"In terms of the bird flu, which is currently devastating the bird population and has made 150 people sick (worldwide), half of which have died, nobody knows if that would ever cause a human pandemic, or if so, when," said Arthur Reingold, professor of epidemiology at the School of Public Health at the University of California at Berkeley.

"But it's possible," Reingold said. "That's what has people nervous, appropriately."

Nonetheless, there are good resources on the Internet where people can get factual, lucid information about the bird flu, its danger and its spread. Here are a few of them.

• The Centers for Disease Control and Prevention hosts Web pages devoted to the subject, offering facts about previous flu pandemics and bird flu.

• The federal government recently set up an official Web site for information on avian flu, at Pandemicflu.gov.

•  The World Health Organization offers regular updates on what's happening globally with the spread of avian flu.

•  The National Institute of Allergy and Infections Diseases has a newly expanded Web site called . The site has 30 reports on research in the field.

Certainly, there's good cause for concern, if history is a guide.

There have been three flu pandemics in the last century, the largest being in 1918, when between 25 percent and 35 percent of the world's population was affected. Known as the "Spanish flu," the virus killed more than 500,000 people in the United States, and about 50 million people worldwide.

Scientists are currently researching genetic mutations of the Spanish flu virus to understand what caused it and to compare it with the H5N1 virus.

Health experts have cautioned that regardless of whether it involves an avian flu or another strain of virus, another human pandemic is as inevitable as devastating earthquakes in California and hurricanes on the Florida coast.

"What are the chances that some kind of pandemic flu will devastate world populations again? It's almost certain," Reingold said.

Avian flu is a contagious disease caused by viruses that normally infect birds and, occasionally, pigs, according to the World Health Organization. The avian flu has also, rarely, crossed the species barrier to infect humans. That happened in 1997, when 18 people were infected in Hong Kong. Six of them died.

In poultry flocks, a highly pathogenic form of the flu can spread rapidly and cause quick degeneration of the animals' internal organs, with death usually occurring within two days--the death rate is close to 100 percent. A less extreme strain produces only mild symptoms.

The largest and most severe outbreak of the latest, highly pathogenic avian flu, H5N1, first appeared in 2003 in Southeast Asia and worsened last year. It's now considered endemic in parts of Indonesia, Vietnam and Cambodia. It has spread to Europe and caused the death of an estimated 150 million birds. The World Health Organization has said that some migratory birds are partly to blame for spreading the virus, and the agency expects its global expansion to continue. Control of the disease in poultry is expected to take several years.

The threat to humans is twofold: More than 100 people in Cambodia and Thailand have been infected from direct exposure to infected poultry, and roughly half of them have died, usually from viral pneumonia and multiorgan failure brought on by the influenza.

The bigger concern for health experts is a mutation that would turn this bird-based bug into a highly infectious strain that could be spread from person to person. And in a world connected by airplanes, such a disease could become a global pandemic in no time.

"The risk of pandemic influenza is serious. With the H5N1 virus now firmly entrenched in large parts of Asia, the risk that more human cases will occur will persist. Each additional human case gives the virus an opportunity to improve its transmissibility in humans, and thus develop into a pandemic strain," according to the World Health Organization.

The Bush administration is proposing funding for research for faster methods of formulating vaccines. Currently, vaccines are made through eggs, and the process takes six to eight months. That's not enough time to act swiftly in the case of a pandemic. The money will also be spent on stockpiling vaccines and antiviral drugs, such as Tamiflu.

"We need more modern ways to make flu vaccines (and)...protect against many strains, rather than just one. So that's certainly money well spent," Reingold said.

Still, he said, referring to state health offices, "federal resources can fix some things, but not necessarily fix all things to be optimally prepared."

Close
Drag
Autoplay: ON Autoplay: OFF