Highly pathogenic avian influenza (HPAI) is a contagious animal disease. Researchers believe the H5N1 virus can infect all bird species, but domesticated poultry are particularly vulnerable. Outbreaks have been attributed to contact between domestic birds and wild waterfowl via shared water sources, as well as to illegal trade in sick poultry and chicken feed by industrial farms.
Over the last twelve months, the disease has gone global, spreading rapidly beyond its East Asian stronghold to countries in South Asia, Europe, Middle East, and Africa (see Figure 1). 55 countries reported H5N1 outbreaks, most of them since January 2006. The impact is severe – an estimated 220 million bird deaths and significant damage to rural livelihoods, especially in the poorest areas.
The disease was first seen in humans in 1997 in Hong Kong. Nearly all human cases are thought to have been contracted from exposure to infected birds. At this time there is no evidence of sustained and efficient human-to-human transmission, but many scientists believe it is only a matter of time until the next flu pandemic occurs.
The laboratory-confirmed impact on people stood at 144 deaths out of 246 infections in ten countries (Azerbaijan, Cambodia, China, Djibouti, Egypt, Indonesia, Iraq, Thailand, Turkey, and Vietnam) as of September 14, 2006; see Table 1. In 2006, about 2 deaths per week were reported in Indonesia, which overtook Vietnam as the country with the most deaths, since Vietnam has not reported any human cases in 2006, reflecting successful control and prevention measures. The North Sumatra cluster infections in May 2006, when human-to-human transmission of H5N1 occurred within an extended family, underscored again the risks of spread of the disease in poultry in Indonesia.
A severe flu pandemic among humans could cost the global economy up to about 3.1 to 4.8 percent of world gross domestic product – between $1.25 trillion and $2 trillion of a world GDP of $40 trillion (see estimates published in GDF, April 2006). The severe-case scenario was based on a 1 percent mortality rate – or about 70 million people.
Impact of a pandemic flu in developing countries would be severe: mortality rates would be about double those in high-income countries, and proportion of GDP lost would be higher as well.
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