The H5N1 flu virus has affected hundreds of thousands of birds, and more than a hundred humans. Health officials are concerned that it will become the next pandemic influenza strain.
What is avian "bird flu"?
There are many different types of influenza viruses circulating in the world at any given time. Some infect only birds, some infect only swine, and others only infect humans.
The term "bird flu" or "avian influenza" refers to influenza strains that affect birds. One particular avian strain, known as H5N1, has caused severe illness in birds in recent years. Hundreds of millions of chickens and ducks have died or been killed in an effort to control this strain of influenza, but the H5N1 virus has been found in birds in many parts of Asia, and is now appearing in other parts of the world as well. The virus is probably being spread by wild birds, who may or may not become ill when infected. Domestic poultry is very susceptible to H5N1.Although the H5N1 virus primarily affects birds, it can also spread to people. Most people who have gotten the virus work directly with poultry, or had close contact with birds. That usually means direct contact with live birds, or bird droppings. So far, it does not appear that people can get it easily from each other.
Why are people concerned about bird flu?
Public health officials are concerned that the H5N1 virus could change (mutate) into a form that is easily spread from one person to another. We don’t know for sure whether that will happen – or when it might happen. But if it does, the result could be a global influenza pandemic. Since few, if any, people would have any immunity to the new influenza virus, it could spread around the world very rapidly, causing serious illness in many people.
Should people be worried about this now?
There is no sign right now that the H5N1 virus has become a pandemic strain. But if it does, It could cause a pandemic like the one that happened in 1918, when millions of people died, or it could cause a less severe pandemic, like like the ones that happened in 1956 or 1968. We simply don’t know. But we need to be prepared in either case. Most health officials believe that a pandemic will happen – it’s just a question of when.
WHO, CDC, and DPH are on constant lookout for the first signs of a pandemic emerging so steps can be taken to try to contain it.
How many people have caught H5N1 so far?
The numbers keep changing. Check these sources to get the latest information.
- H5N1 Avian Influenza Statistics
Latest case counts for humans, plus lists of countries affected by H5N1.
- Avian Influenza Frequently Asked Questions
WHO (World Health Organization) overview of avian influenza, the effects on birds, and the possibility of H5N1 becoming the next influenza pandemic for humans.
- Avian Influenza
The United Kingdom Health Protection Agency addresses the present situation, control measures in birds, human-to-human transmission, symptoms, travel advice, and vaccines.
- Avian Influenza (Bird Flu)
CDC provides background information about avian influenza, including recent outbreaks, the viruses, and the risk to human health.
- Key Facts About Avian Influenza (Bird Flu) and Avian Influenza A (H5N1) Virus
CDC fact sheet describing bird flu, including definitions, transmission, symptoms, treatment, and risk to people in both Asia and the United States.