How are Seasonal, Avian and Pandemic Flu different?

Seasonal Flu

A contagious respiratory infection caused by influenza (flu) viruses, seasonal flu is transmitted by when infected people sneeze or cough. People become ill within one to five days from when they are infected. Most people have some immunity to this virus, and a vaccine is available.  Click here for more information on the Department of Health and Human Services Flu Shot Program.  According to the World Health Organization, since 2003 the Asian H5N1 Virus has caused 115 deaths.  Compare that to 30,000 deaths per year caused by seasonal influenza.  Click here for more information about seasonal flu prevention. 

Avian Influenza

Avian influenza is an infection caused by avian influenza viruses. These influenza viruses occur naturally among birds. Wild birds worldwide carry the viruses in their intestines, but usually do not get sick from them. However, avian influenza is very contagious among birds and can make some domesticated birds, including chickens, ducks, and turkeys, very sick and kill them.

Influenza A (H5N1) virus – also called “H5N1 virus” – is an influenza virus that occurs mainly in birds, is highly contagious among birds, and can be deadly to them. H5N1 virus does not usually infect people, but infections with these viruses have occurred in humans. Most of these cases have resulted from people having direct or close contact with H5N1-infected poultry or H5N1-contaminated surfaces.

Infected birds shed influenza virus in their saliva, nasal secretions, and feces. Susceptible birds become infected when they have contact with contaminated body fluids or with surfaces that are contaminated with secretions or excretions from infected birds. Domesticated birds may become infected with avian influenza virus through direct contact with infected waterfowl or other infected poultry, or through contact with surfaces (such as dirt or cages) or materials (such as water or feed) that have been contaminated with the virus.

Only in rare instances are these viruses passed to other animals and people — usually through bodily fluids from infected birds. For information on the Asian H5N1 strain of Avian Flu, click here.

Pandemic Flu

Flu pandemics occur when there is a major change in the genetic make up of a virus, which results in a new strain to which people have not been previously exposed. This causes a global outbreak, or pandemic.

All humans are susceptible, attack rates are high and mortality rates may be high as well. Pandemic influenza spreads rapidly and can circle the world in only a few months.  Currently, there is no pandemic flu.