About Influenza
Influenza, commonly called the flu, is a viral infection. There are many different strains and types--from the seasonal flu to H1N1 (swine flu) and bird flu. But they're all caused by viruses and generally transmitted in similar ways. Symptoms of the flu might vary, but they generally include coughing, sneezing, fever, body aches, headaches and sometimes vomiting or nausea.
In the Air
The influenza virus is an airborne illness. When a person who has influenza coughs or sneezes into the air, the virus can be spread to someone else who breathes the same air. It's called droplet spread, according to the Centers for Disease Control and Prevention. You can also catch the influenza by touching contaminated droplets with their hands, then putting your hands to your nose, eyes or mouth.
Skin and Contact
You also can contract the flu by kissing or having any physical contact with someone who has the virus--even just shaking hands, says the Palo Alto Medical Foundation. That's why it's important to wash your hands frequently and thoroughly, particularly after being around someone who is sick. Touching someone who is sick, then putting your hands on your nose, eyes or mouth can spread the virus.
Timeline for Contagiousness
According to the CDC, most adults can be contagious and spread the disease for up to eight days. They can infect someone else a day prior to the onset of symptoms and as long as five to seven days after they notice symptoms. Children tend to be contagious longer, and could spread the illness for upwards of seven days. If you have contracted the virus, you'll typically become sick one to four days after exposure. But, you can also carry the virus and spread it to others without ever actually becoming sick yourself, notes the CDC.
