The UN is warning of a major humanitarian crisis if the influenza pandemic hits developing countries already ravaged by poverty and conflict.The UN humanitarian chief says officials are desperately trying to plan for emergencies in poor countries. The possibility of relief workers being affected by the flu is also causing major concern. As countries in the West race to stock up on antiviral medications, there is growing debate about what is available to developing nations. The H1N1 virus has now killed more than 700 people worldwide since emerging in April. However, the World Health Organisation says it is up to national health authorities to decide what measures they impose to slow the spread of the new strain. It also says this is the fastest-moving pandemic ever and it is now pointless to count every case. It is telling countries to concentrate on what it calls “mitigation measures”.