Influenza A/H5N1 is the strain of influenza currently spreading throughout the world. Although it is a bird flu, it has infected a relatively small number of people -- killing more than half of those infected. Some scientists are concerned that H5N1 may cause the next influenza pandemic. Flu pandemics have occurred cyclically, between every 30 and 50 years. Since 1997, when the first human contracted H5N1 in Hong Kong, the virus has resurfaced and spread to nearly fifty countries in Asia, Europe, the Middle East, and Africa -- infecting more than 190 people. In February 2006, the virus spread from Asia and central Europe to western Europe. In March 2006, health experts confirmed new bird flu cases among more than 20 countries across Europe, Asia, and Africa. Most of the countries were experiencing their first H5N1 cases. The first human H5N1 fatalities outside of Asia occurred in 2006 when Turkey and Iraq announced their first human deaths related to H5N1 infection in January 2006 and February 2006, followed by Azerbaijan and Egypt in March 2006. A global influenza pandemic could have a number of consequences. Global competition for existing vaccines and treatments could ensue. Some governments might restrict the export of vaccines or other health supplies to treat their own population. Some countries might face a shortage of vaccines, antiviral medication, or other medical equipment, because of limited global supply. Hospitality and airline industries, and international trade could be negatively impacted. If global travel and trade were to suddenly drop, there could be productivity losses and service disruptions. Essential workers might become ill or stay home out of fear of contracting the virus. Such workers could include law enforcement, medical personnel, mass transit drivers and engineers, and other crucial emergency personnel. Congress provided $31.3 million for international avian flu activities through FY2005 emergency supplemental appropriations. FY2006 emergency supplemental appropriations reserved $280 million for global H5N1 initiatives. The Administration requests $215 million for global H5N1 containment activities in FY2007. Bills introduced in the 109th Congress would increase U.S. resources allocated to the global fight against avian flu; develop a "Pandemic Fund" to augment ongoing U.S. and international avian flu and pandemic preparedness initiatives; increase funding for preventing the spread among animals of the H5N1 virus; and strengthen surveillance capacity within affected countries. This report provides an up-to-date account of global H5N1-related human infections and deaths, outlines U.S. government response to the global spread of H5N1, and presents some foreign policy issues for Congress. This report will be periodically updated. For more information on H5N1, U.S. domestic preparedness efforts, agricultural issues, and the efforts of overseas governments to combat the spread of avian influenza, please see CRS Report RL33349, International Efforts to Control the Spread of the Avian Influenza (H5N1) Virus: Affected Countries' Responses, by Emma Chanlett-Avery; CRS Report RS21747, Avian Influenza: Agricultural Issues, by Jim Monke; and CRS Report RL33145 -- Pandemic Influenza: Domestic Preparedness Efforts, by Sarah A. Lister. [ABSTRACT FROM AUTHOR]