Influenza, commonly known as the flu, is a highly contagious respiratory illness caused by a virus. It is spread from person to person through the air, usually when an infected person coughs, sneezes, or talks. It can also be spread when a person touches a surface or object that has the virus on it and then touches their eyes, nose, or mouth.
The flu virus is present in a person's respiratory secretions, which means it can be spread through droplets in the air when an infected person coughs, sneezes, or talks. These droplets can land on the mouths or noses of those who are nearby and then they can become infected. The virus can also be spread through contact with objects and surfaces that have the virus on them, such as doorknobs, keyboards, and phones. If a person touches one of these surfaces and then touches their eyes, nose, or mouth, they can get infected with the virus.
People are most contagious during the first two to three days of their illness, but they can still spread the virus for up to a week after they start showing symptoms. It is important to practice good hygiene to help prevent the spread of the virus, such as washing your hands frequently with soap and water, avoiding close contact with people who are sick, and staying home when you are sick. Vaccination is also an important way to protect yourself from the flu and other contagious illnesses.