Avian influenza (also referred to as avian flu or bird flu) refers to type A strains of the influenza virus that infect birds. Avian flu occurs worldwide and was first identified over 100 years ago. Normally avian flu viruses don't infect species other than birds and pigs. In 1997, however, the first documented human case of avian flu occurred in Hong Kong. Avian flu causes severe symptoms and can result in death.
Multiple countries have reported outbreaks of avian flu in their poultry populations, and several countries have had confirmed cases of people infected with avian flu. The World Health Organization provides maps that show affected countries.
Your risk of contracting avian flu depends on your proximity to infected poultry, so there is currently minimal risk for members of the UM community in the United States.
Transmission can occur from infected poultry, primarily chickens and ducks, or their feces to humans and other poultry. Furthermore, birds that survive infection can still transmit the virus for at least 10 days. There is no evidence that eating properly cooking poultry or eggs can cause infection. Limited person-to-person transmission has been reported.
While 15 subtypes of influenza can infect birds, only a few of these have been known to infect people. The first reported strain of avian flu to infect humans is also the most common and most pathogenic, and is called H5N1. Two other strains, H7N7 and H9N2, have also been reported to infect humans. Migratory birds do carry avian flu viruses, but usually in the low pathogenic form. For this reason efforts are focused on poultry that are more likely to carry the highly pathogenic form of H5N1.
There is minimal risk of contracting avian flu from poultry in most parts of the world, including North America. While a few instances of person-to-person transmission have been reported, the H5N1 strain of the virus has not mutated to allow easy transmission from one person to another. Also, the H5N1 strain is known to mutate rapidly, increasing the possibility that it may mutate to the point where it can be transmitted from one person to another.
You are at increased risk of contracting avian flu if you live in or travel to a risk area that is experiencing an avian flu outbreak in poultry. Furthermore, the H5N1 strain of avian flu is now present in many parts of Asia, increasing the chance that humans will become infected by infected poultry. Each time this occurs, there is a chance that the virus will develop the ability to pass from human to human. If this adaptation occurs, it will no longer be a bird virus; it will be a human influenza virus. Influenza pandemics are caused by new influenza viruses that have adapted to humans.
A pandemic outbreak of flu in humans would be a severe global problem. The flu virus can spread rapidly through sneezing and coughing, and those infected could transmit before they even develop symptoms. No one can predict where or when a pandemic would start or if one will occur at all, but as the H5N1 strain moves to more parts of Asia and other parts of the world, the chance increases.
Symptoms of avian flu in humans consist of normal flu-like symptoms of coughing, sore throat, muscle-ache and fever. Eye infections, pneumonia, acute respiratory distress and other severe life-threatening complications can also accompany the disease.
The best thing you can do is stay away from infected poultry and their feces in risk areas. If traveling in risk areas, take precautions to minimize your risk.
Unfortunately, because avian flu is a virus that mutates, no effective vaccine has been developed. The yearly flu shots that protect against seasonal flu have no direct affect against avian flu. Research is underway to develop a vaccine; see the National Institute for Allergy and Infectious Diseases website.
Limited studies show that both oseltamivir (Tamiflu) and zanamivir (Relenza) can increase survival rates if taken within 48 hours after symptoms develop. These drugs are not a preventive treatment - they work after infection has occurred.
Together, University Health Service, University Housing, UM Health System, Occupational Safety and Environmental Health, other campus units and the Washtenaw County Health Department plan for contagious disease prevention and response, including pandemic influenza.