Current fatality rate for human-acquired H5N1 avian influenza: 63%
Potential infection rate, as compared to the 1918 Spanish Flu: 50%
Current world population: 6,850,000,000
50% of this, x 63% = 2,000,000,000 - that's 2 billion potential deaths over several months.

I guess that might have an impact on the current financial crisis, among other things.

Health experts have been closely monitoring the H5N1 strain because it has already met two of three conditions that could spark an influenza pandemic (global epidemic). It is a new influenza virus subtype and it infects humans, causing serious illness. The third condition is that the virus spreads easily on a sustained basis among humans. If the H5N1 evolves into a form that is as contagious as normal influenza, it could start a pandemic.

"The risk that avian influenza could cause the next pandemic remains the same. It has not changed at all since 2003," Kasai said.

He said the avian flu virus continues to mutate. "In 1997 there was only one strain, now there are more than 10 groups," he said. "We have already seen changes in the virus."

As long as opportunities for human infections occur, the risk that the H5N1 virus will acquire the ability to cause an influenza pandemic will persist, the WHO said. And these opportunities will remain as long as the virus circulates in birds.