Dialogue: Avian flu, the facts
Kenneth McIntosh, MD, is chief emeritus of the Department of Infectious Diseases and a world expert in respiratory viruses
What is avian influenza (bird flu)?
Bird flu is an infection caused by avian influenza viruses. These flu viruses occur naturally among birds and are carried in their intestines. Wild birds don't usually get sick from them; however, bird flu is very contagious among birds and can make some domesticated birds, including chickens, ducks and turkeys, very sick and kill them.
How does bird flu differ from the seasonal and pandemic flus?
Seasonal flu is the influenza that occurs every winter in the United States, killing about 36,000 people annually. Pandemic flu occurs much more rarely and only when a new strain of influenza virus appears that people have no immunity to. Currently, there is no pandemic flu strain in circulation. However, experts fear that if the bird flu strain we're hearing about in the media mutates to a human strain, it could spread around the world within several weeks to months. Currently, the media are talking about all three forms, seasonal, bird and a potential pandemic flu.
Do bird flu viruses infect humans?
Bird flu viruses don't usually infect humans, but several cases of human infection with bird flu viruses have occurred worldwide since 1997.
What are the symptoms of bird flu in humans?
Symptoms range from typical flu-like symptoms—fever, cough, sore throat and muscle aches—to eye infections, pneumonia, severe respiratory diseases, such as acute respiratory distress, and other severe and life-threatening complications. The symptoms of bird flu may depend on which virus caused the infection.
Is it safe to eat chicken?
Avian flu is not a food-borne virus, so eating cooked chicken is safe. For more information about avian flu and food safety issues, visit the World Health Organization Web site: www.who.int/en.
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How does bird flu spread?
Infected birds shed flu virus in their saliva, nasal secretions and feces. Susceptible birds become infected when they have contact with contaminated excretions from other infected birds or surfaces contaminated with excretions. It's believed most cases of bird flu infection in humans have resulted from close contact with infected poultry or contaminated surfaces. The spread of avian influenza viruses from one person to another has been reported very rarely, and transmission has not been observed to continue beyond a single person.
How is bird flu in humans treated?
Studies done in laboratories suggest prescription medicines approved for human flu viruses should usually work in treating bird flu infection in humans. However, flu viruses can become resistant to these drugs, so these medications may not always be effective.
What is the risk to humans from
bird flu?
The risk from bird flu is generally low to most people because the viruses occur mainly among birds and don't usually infect humans. However, during an outbreak of bird flu among poultry—domesticated chicken, ducks, turkeys—there's a possible risk to people who have close contact with infected birds or surfaces that have been contaminated with excretions from infected birds. The current outbreak among poultry in Asia and Europe is an example of a bird flu outbreak that has caused human infections and deaths. In such situations, people should avoid contact with infected birds or contaminated surfaces, and should be careful when handling and cooking infected poultry.
What is the actual risk of an outbreak of bird flu or a pandemic this year?
It's difficult to know. The real fear is that the virus could exchange genes with a human flu virus if a person or animal is simultaneously infected with both. This could make a new, stronger strain of flu that, if not carefully contained, could travel from person to person creating a pandemic. Mortality rates could be very high since effective treatment is uncertain with any new virus.
If I got a flu shot earlier this year, will that protect me against bird flu?
The flu shot you got earlier this year protects against common strains of the seasonal flu; it is not designed to combat bird or pandemic flu.
Is Children's preparing for potential outbreaks?
Children's is working closely with local and state public health authorities. Guidelines have already been provided in the event that suspect cases of bird flu present in the area. In October, Children's participated in a city-wide drill focusing on bird flu. We're also preparing for the regular influenza season, as members of Infection Control, Infectious Diseases, Pharmacy, Materials Management, Safety, the Emergency Department and Emergency Management continue to evaluate our methods for patient triage surveillance, vaccination, prophylaxis and treatment, along with ensuring enough equipment and supplies are available.
