
What Is Flu and How Is It Caused? Influenza, or flu, is a contagious respiratory disease caused by a virus. when someone who has flu sneezes or coughs, the flu virus is expelled into the air where it may be Read More …
What Is Flu and How Is It Caused? Influenza, or flu, is a contagious respiratory disease caused by a virus. when someone who has flu sneezes or coughs, the flu virus is expelled into the air where it may be Read More …