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 spread quickly through populations. Symptoms typically include fever, cough, sore throat, body aches, and fatigue. Vaccines are available to help protect against Influenza A, and they are updated annually to match circulating strains. The virus is transmitted through respiratory droplets when an infected person coughs or sneezes, making it important to practice good hygiene to prevent its spread.