Frequently Asked Questions About Avian Flu

Seasonal (or common) flu is a respiratory illness that can be transmitted person to person. Most people have some immunity, and a vaccine is available. Every year in the United States, on average:

• 5% to 20% of the population gets the flu;
• More than 200,000 people are hospitalized from flu complications, and;
• About 36,000 people die from flu.
• Some people, such as older people, young children, and people with certain health conditions are at high risk for serious flu complications.
Reference: Centers for Disease Control and Prevention)

Avian (or bird) flu is caused by influenza viruses that occur naturally among wild birds. The H5N1 variant is deadly to domestic fowl and can be transmitted from birds to humans. There is no human immunity and no vaccine is available. Despite the fact that an estimated 150 million birds have died or been destroyed, the virus has become endemic in some areas and is being spread world wide by migratory birds.

Pandemic flu is a virulent human flu that causes a global outbreak, or pandemic, of serious illness. Because there is little natural immunity, the disease can spread easily from person to person. Currently, there is no pandemic flu.

Outbreaks in wild and domestic birds have been reported in many countries, 10 of which have also reported human deaths. Those countries are:

• Azerbaijan
• Cambodia
• China
• Djibouti
• Egypt
• Indonesia
• Iraq
• Thailand
• Turkey
• Viet Nam

(Reference: World Health Organization)

Widespread persistence of H5N1 in poultry populations poses two main risks for human health. The first is the direct infection from poultry to humans. The second threat is the emergence of a mutant strain that spreads easily from person to person. Confirmed cases of bird-to-human transmission have occurred in four countries: Cambodia, Indonesia, Thailand and Vietnam. As of May 29, 2006, 224 cases have been confirmed resulting in 127 deaths.

The bird-to-human transmission occurs from direct contact with infected poultry or surfaces and objects contaminated by their blood or feces. Exposure to the virus is most likely during slaughter, de-feathering, butchering and preparing poultry for cooking. Currently, there is no evidence that properly cooked poultry or eggs are a source of infection.

The virus can become transmissible among humans by either a "reassortment" event or by a more gradual process of adaptive mutation. In "reassortment" genetic material is exchanged between human and avian viruses when there is co-infection in a human, pig or other animal. This results in a new potent strain that is fully transmissible to humans. The process of adaptive mutation is a more gradual process by which the virus becomes more efficient at binding to human cells.

A pandemic can start when three conditions have been met:

1. A new virus subtype emerges;
2. It infects humans;
3. Spreads easily and is sustained among humans.

The first two conditions have been met in that a new subtype has emerged and humans have been infected through contact with infected birds.

Some vaccine clinical trials are currently under way. Because the antigen needs to closely match the pandemic virus, large scale production cannot start until a pandemic virus has emerged.

Tamiflu and Relenza are oral antivirals that are available and are effective for reducing the severity and duration of viral illness. Medical experts tell us that these medications can also be used prophylactically to decrease the number of new cases when an exposure has occurred.

The CDC and WHO are not recommending that individuals avoid traveling to affected areas at this time. Both health organizations have posted recommendations regarding safe travel to these regions. Recommendations include avoiding direct contact with birds, poultry and livestock, and eating only poultry and eggs that have been thoroughly cooked. Before traveling to these regions, check the CDC or WHO Web sites for up-to-date information. Links are provided below.

• CDC Traveler's Health
• WHO - Avian Influenza
• WHO - Avian Influenza FAQ

References: World Health Organization/Centers for Disease Control