Bird-flu spread: "Nature is in control"

The spread of avian influenza through at least 29 new countries in the past seven weeks — one of the biggest outbreaks of the virus since it emerged nine years ago — is prompting a sobering reassessment of the strategy that has guided efforts to contain the disease.

Since February, the virus has cut a swath across the globe, felling tens of thousands of birds in Nigeria, Israel, India, Sweden and elsewhere. Health officials in the United States say bird flu is likely to arrive in North America this year, carried by wild birds migrating to their summer breeding grounds.

The speed of the virus' migration, and the vast area it has infected, has forced scientists to concede there is little that can be done to stop its spread across the globe.

"We expected it to move, but not any of us thought it would move quite like this," said Dr. David Nabarro, the United Nations' coordinator on bird-flu efforts.

The hope once was that culling millions of chickens and ducks could contain or even eradicate the virus. Now, strategy has shifted toward managing a disease that will probably be everywhere. Officials are hoping to buy a little more time to produce human vaccines and limit the potential economic damage.

Bird-flu spread: "Nature is in control"