Influenza A is a type of virus that causes seasonal flu outbreaks in humans and can also infect animals, particularly birds and pigs. It is known for its ability to change rapidly, leading to new strains that can evade the immune system. This characteristic makes it a significant public health concern, as it can lead to widespread illness. The symptoms of Influenza A typically include fever, cough, sore throat, body aches, and fatigue. Vaccines are available to help prevent infection, and antiviral medications can reduce the severity and duration of the illness if taken early.