What is flu (influenza)?
Flu, or influenza, is a contagious illness caused by the flu virus. It attacks the nose, throat and lungs in people. Anyone, including healthy people, can get the flu. Serious health problems from the flu can happen at any age. What are the types of flu viruses? There are three types of flu viruses: A, B, and C. Influenza type A viruses can infect people, birds, pigs, horses, seals, whales and other animals. Wild birds are the natural hosts for these viruses. Influenza B viruses are usually found only in humans. Influenza type C viruses cause mild illness in people. How are seasonal flu, avian influenza (bird flu) and pandemic flu different? • Seasonal flu follows predictable yearly patterns, in Texas generally from October through March. Viruses associated with seasonal flu include influenza A, influenza B and influenza C. People usually have some immunity built up from previous exposure to circulating seasonal flu viruses. • Avian influenza (bird flu) is an infection caused by bird f
