Pandemic flu: A flu pandemic is a global outbreak that occurs when a new influenza A virus causes serious human illness and spreads easily from person to person.
Avian flu: Avian, or bird, flu occurs naturally among birds. All bird flus are influenza A. There are many strains of avian flu viruses, some more virulent than others.
Seasonal flu: This is the influenza virus that tends to infect people each year during the winter months. In many people, its symptoms are mild and last no more than a week. However, about 36,000 Americans die of seasonal influenza each year.
Influenza A: Influenza A viruses are found in many different animals, including ducks, chickens, pigs, whales, horses, and seals. Influenza A is primarily a respiratory disease, causing cough, congestion, sore throat, muscle aches, fatigue, and fever in most species it infects.
Influenza B: This virus circulates widely only among humans. It generally does not make people as sick as influenza A does.
This information was developed in conjunction with the Montana Department of Public Health and Human Services (DPHHS).
