SINGAPORE (CNA) – The World Bank estimates that a severe flu pandemic could cost the global economy up to $2 trillion, or 4.8 percent of the world's gross domestic product.

Over the past year, the avian flu has gone global - spreading beyond East Asia to Europe, Middle East and Africa.

To help developing countries fight it, the World Bank on Sunday announced a $15 million grant to Indonesia.

In the worst-case scenario of a flu pandemic, 70 million people - or 1 percent of those infected - could die from it.

And the World Bank says developing countries would be worse hit - with mortality rates being double than in high-income countries.

Jim Adams, Head, World Bank Avian Flu Taskforce, said, "We estimate that a severe pandemic could now cost over 3 percent of the global economy's GNP, because of its impact on trade and economic activity. "We estimate this could cost, in fact, certainly over $1 trillion and perhaps as high as $2 trillion in the worst-case scenario. So I think the threat, the economic threat, remains real and remains substantial."

Fifty-five countries have reported H5N1 outbreaks, most since January this year.

About 80 percent of the 240 human cases, and 141 deaths happened in Asia.

And the World Bank wants to do more to help Asia battle the disease, starting with a new $15 million grant to Indonesia - the worst-hit with 59 cases and 46 deaths so far.

Dr David Nabarro, Senior UN System Influenza Coordinator, said, "Indonesia badly does need money to continue to spread its avian influenza control efforts through all the 440 districts in the country. "The money that is being discussed today is a small amount of money, but it's an important amount of money that's going to make a difference...So $15 million is a start...But I'm currently appealing for more money for Indonesia so that the good work that has been done can be expanded further."

So far, $1.2 billion has been committed to specific programmes to tackle avian flu in developing countries.

Over $330 million has been disbursed.

The World Bank says this is a more rapid response than what was seen in the aftermath of recent major natural disasters like the Indian Ocean tsunami.