Avian influenza, commonly known as the bird flu, is a contagious disease caused by a set of viruses that typically infect birds and, in very rare cases, pigs. The viruses tend to be highly species-specific, but have also been known to affect humans.

How Common Is Avian Flu?

The highly pathogenic H5N1 virus (a subtype of the Influenza A virus) is of present concern because between December 2003 and early February 2004, eight Asian nations reported outbreaks among their poultry: the Republic of Korea, Vietnam, Japan, Thailand, Cambodia, Lao People's Democratic Republic, Indonesia, and China. Soon after, Malaysia, Russia, Kazakhstan, Turkey, and Romania followed. Currently, Japan, the Republic of Korea, and Malaysia have reportedly controlled their poultry outbreaks and are said to be cured of the disease, but the outbreaks still remain at different degrees of severity in the other affected areas.

How Dangerous Is Avian Flu?

The H5N1 virus poses two main threats to human health, the first of which is direct transmission from poultry to humans, causing very severe disease. Not many avian flus have made it past the species divide, but H5N1 has been the most fatal so far. Unlike typical flu, which causes only mild respiratory symptoms, H5N1 results in a very aggressive clinical course, with hasty deterioration and high mortality. Primary viral pneumonia and multi-organ failure are common. Presently, more than half of those people who have acquired the virus have died, according to the Centers for Disease Control and Prevention (CDC).
The second, even more frightening, potential threat to human health is if the virus were to mutate into a form that is highly infectious for humans and can easily be transmitted from person to person. This would mark the start of a pandemic. In the current outbreak, confirmed human cases have been reported in four countries: Indonesia, Cambodia, Thailand, and Vietnam.

Protecting People Against Avian Flu

According to the World Health Organization (WHO), the best way to ward off the potential pandemic would be to eliminate the virus from the birds themselves, but this is proving to be exceedingly difficult. In August 2005, the WHO sent all countries a document detailing recommended actions for reacting to the avian influenza pandemic threat. These actions are intended to increase awareness, improve the early warning system, stall initial worldwide spread, and speed up vaccine development.