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Bird flu, or avian influenza, is forcing the slaughter of millions of poultry in Asia, Africa and Europe. The virus has crossed over from birds to infect humans. As of February 2008, at least 226 people have died. What do you know about bird flu, and how will it affect you? |
What is Avian Influenza?
Avian influenza, or “bird flu,” is a contagious disease caused by viruses that normally infect birds and, less commonly, pigs and other animals. Humans can also be infected if they have direct contact with diseased birds or indirect contact through uncooked poultry products or contaminated surfaces or water.
The virus has two forms: “low pathogenic” and “highly pathogenic.” Low pathogenic forms may cause mild illness in birds and mild infections and flu-like symptoms in humans. Highly pathogenic forms result in death for 90 to 100 percent of infected birds and in severe or life-threatening respiratory distress in humans.
In addition to posing a health threat, avian influenza has economic repercussions. While all bird species are thought to be susceptible, domestic poultry flocks are especially vulnerable. Culling (destroying all infected or exposed birds) and quarantine are the standard methods to contain outbreaks of the disease in birds. The economic repercussions on poultry farmers can be severe. The World Health Organization has estimated that avian flu has cost global agriculture more than $10 billion and has affected the livelihoods of 300 million farmers.
Does Avian Influenza Pose a Serious Public Health Threat?
Since December 2003, public health officials in Asia, Africa and Europe have reported an increase in outbreaks of H5N1, a highly pathogenic strain of avian influenza, in poultry. The rapid spread of the disease is of great concern to public health and animal health officials worldwide.
Particularly alarming is the escalating incidence of infection in mammals. H5N1 is causing severe disease and fatalities in pigs, tigers and humans in gradually growing numbers. As of February 2008, at least 359 humans have contracted the disease.
A second and even greater concern is the possibility of an influenza pandemic in humans. So far, rare and “dead end” cases of human-to-human transmission have been reported, but no sustained human-to-human transmission of the H5N1 virus has been identified. However, if a person were infected simultaneously with bird flu and human flu, the viruses would have the opportunity to exchange genes. This process of “gene swapping” could give H5N1 the ability to jump rapidly from human to human. Few, if any, humans would have natural immunity, and vaccines for seasonal flu would not be effective. An influenza pandemic, with high rates of illness and morbidity, could result.
Reports CDC Director, Dr. Julie Gerberding, “In the absence of any control measures, such as vaccination, between 15 percent and 35 percent of the United States population could be affected by an influenza pandemic, and the economic impact in our country alone could range between $71.3 and $166.5 billion.”
Are vaccines or treatments available?
Researchers are making and testing possible H5N1 vaccines now. The first H5N1 vaccine for humans was approved by the U.S. FDA in April 2007. The vaccine is being stockpiled but currently is not commercially available. In a clinical trial, the vaccine protected about 45 percent of adults vaccinated with the highest dose (seasonal flu shots usually protect more than 90 percent of healthy adults.) Research continues on additional vaccines to combat H5N1, including cell-based vaccines, which could be produced more quickly than current egg-based vaccines if an outbreak occurred.
Two types of antiviral drugs have been approved for use in the United States to treat human influenza infections. Currently, CDC’s Strategic National Stockpile contains enough antiviral drugs to treat 20 million people. An additional 24 million courses are scheduled to arrive in 2008.
How is CDC Responding?
CDC is responding to this public health emergency by working closely with its domestic and international partners to monitor the virus and help contain it.
CDC has joined with U.S. regulatory agencies to prevent the H5N1 strain of avian influenza from entering the U.S. These measures include a ban on the importation of birds from affected regions of Asia, and in April 2005 the President added influenza viruses that have the potential to cause a pandemic to the list of quarantinable diseases. CDC has issued a series of travel notices and has expanded the number and capacity of its quarantine stations at major ports of entry into the United States.
CDC also is preparing for the possibility that avian flu could cross U.S. borders. In November 2005, CDC’s parent agency, the Department of Health and Human Services (HHS), released its Pandemic Influenza Plan, a detailed guide for how the United States health care system can prepare for and respond to an influenza pandemic. It is the medical and public health component of the National Strategy for Pandemic Influenza. The HHS plan specifies four major components of preparedness and response to pandemic influenza:
- Intensifying surveillance and collaborating on containment measures — both international and domestic;
- Stockpiling of antivirals and vaccines and working with industry to expand capacity for production of these medical countermeasures;
- Creating a seamless network of Federal, state and local preparedness, including increasing health care surge capacity; and
- Developing the public education and communications efforts so critical to keeping the public informed.
The plan also provides guidance to state and local partners on topics including: staffing and supplies required for a surge in patients; distribution of vaccines and antiviral drugs, particularly when they are in short supply; roles and responsibilities for decision makers in a community; and measures to control infection and limit the spread of disease.
Internationally, CDC is collaborating with the World Health Organization to improve surveillance of avian flu. CDC experts are helping expand the surveillance capacity of local Asian and African communities by providing laboratory assistance and laboratory training, and by distributing kits to help local public health officials detect and report occurrences of H5N1 infection.
How Can I Help?
The CDC Foundation supports a variety of programs that help CDC protect the public’s health and safety from threats like avian influenza. Through its Emerging Infectious Diseases fellowship programs, the CDC Foundation has supported numerous fellows to train or work at CDC, including Doan C. Nguyen, M.D., a Vietnamese laboratory researcher, who studied avian influenza.
The CDC Foundation also supports CDC efforts to prepare for potential public health emergencies like a pandemic flu situation. After the September 11 attacks, the CDC Foundation partnered with the Marcus Foundation to create CDC’s Marcus Emergency Operations Center, a state-of-the-art facility that serves as CDC’s command central during emergency situations. The CDC Foundation also established the Emergency Preparedness and Response Fund to provide CDC responders with immediate, flexible resources during public health emergenices.
Learn more about how you can help by supporting the CDC Foundation.