The World Health Organisation provides all the latest updates on bird flu. This fact sheet is a good place to start for an introduction to the virus in birds and humans.

If you want to know more about the impact of the disease on those whose livelihoods depend on poultry try the Food and Agriculture Organisation's bird flu site.

It's a well written and presented site with animated graphics, slide shows and question and answer sections as well as academic reports and research papers.

This AlertNet article Bird flu threatens millions of poor describes the devastating effect the virus is already having on people's livelihoods in Asia and Africa.

You'll find information about compensation in this short, clear World Bank summary which spells out the general bird flu situation at the beginning of 2007.

A useful feature on the FAO site is the gallery of maps which is regularly updated as bird flu spreads around the world.

There's a good animated graphic illustrating the spread of the disease and the role of migratory birds.

For an animated guide explaining why chickens are such a crucial source of income for millions of families in Vietnam and a useful map showing how bird flu has hit the country's poorest areas click here.

The World Bank's avian flu website provides information on programmes to prevent the disease and describes the potential economic impact - $800 billion a year according to one bank economist.

But that sum is peanuts compared to the worst-case scenario predicted by the Lowy Institute for International Policy. A severe pandemic could kill 140 million people and cost the world $4.4 trillion, according to a report by the independent Australian think-tank which also lays out a range of less scary forecasts.

The Asian Development Bank says even a mild pandemic could kill 3 million in Asia alone and cost the region $300 billion. Its site has background and papers on the potential economic impact in Asia.

The U.N. news service IRIN has also put together a bird flu section with reports from around the globe and interactive maps.

The U.N.'s Food and Agriculture Organization highlights research by FAO and other experts which demonstrates that ducks, population size and rice cultivation, rather than chickens, are the significant factors in bird flu outbreaks.

For information on the risk to the United States visit the Centers for Disease Control and Prevention. Its bird flu section has some of the most easy to understand general background on the disease.

The European Centre for Disease Prevention and Control focuses on the risks to Europe but is a lot more technical in tone than the CDC site.

The World Organisation for Animal Health, which was set up in 1924 to help countries work together to eradicate diseases threatening their livestock, keeps its site regularly updated with news of the latest outbreaks. It also has information in French and Spanish.