Avian influenza: preparing for a pandemic.

Avian influenza A (H5N1) first emerged as a global public health threat in 1997 when it caused a major human outbreak in Hong Kong. Endemic in waterfowl and highly virulent in poultry, H5N1 is capable of incidentally infecting humans and other mammals. Although H5N1 is not yet capable of efficient human-to-human transmission, the protean nature of its genome could transform it into the source of the next human influenza pandemic. In the spring of 2006, migrating birds spread the virus from Asia to Europe and Africa. Preparing for a new influenza pandemic involves increasing global influenza surveillance and developing practical strategies for containing outbreaks at the source. Prompt case recognition, isolation, and treatment will be crucial for disease control. Pharmacologic interventions will focus on streamlining the production of vaccine, extending vaccine supplies, stockpiling antiviral drugs such as oseltamivir, and distributing these agents in a timely manner to persons who have the most need. Nonpharmacologic measures will include the use of masks, social distancing, quarantine, travel restrictions, and increasing the emergency capacity of health care systems.