A contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to death. The best way to prevent the flu is by getting a flu vaccination each year.
Overview. The influenza virus, conversationally called the flu, is an illness that's highly contagious and causes a number of different symptoms. There are many different types, or strains, of the influenza virus, including the seasonal flu virus and the H1N1 influenza virus (commonly called swine flu). Influenza (also known as the flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to death. The best way to prevent the flu is by getting a flu vaccination each year. Causes of the flu. The flu is caused by influenza virus types A, B, and C. Both type A and type B flu viruses are responsible for the seasonal outbreaks of flu. Type A flu viruses are found in many different animals, including ducks, chickens, pigs, and horses. Influenza B viruses circulate widely only among humans. Influenza A is a commonly found type of flu that is found in mainly mammals. It is a type of virus that is most commonly found to harm the throat, nasal, head, and lungs. The flu is caused by influenza virus types A, B, and C. Both type A and type B flu viruses are responsible for the seasonal outbreaks of flu. Type A flu viruses are found in many different animals, including ducks, chickens, pigs, and horses. Influenza B viruses circulate widely only among humans. Although initially symptoms of influenza may mimic those of a cold, influenza is more debilitating with symptoms of fatigue, fever, and respiratory congestion. Colds can be caused by over 100 different virus types, but only influenza viruses (and subtypes) A, B, and C cause the flu. 1 Influenza, commonly called the flu, is caused by viruses that infect the respiratory tract. 2  Symptoms include fever, chills, cough, sore throat, headache, muscle aches, and fatigue. 3  The incubation period for flu is about one to four days.
http://www.livestrong.com/article/30957-influenza-virus-characteristics/ http://www.concentra.com/patients/health-library/influenza/ http://www.concentra.com/patients/health-library/influenza/ http://www.answers.com/Q/What_is_a_key_characteristic_of_pandemic_influenzas http://www.concentra.com/patients/health-library/influenza/ http://www.medicinenet.com/influenza/article.htm http://www.medicinenet.com/influenza/article.htm
what is a characteristic of influenza